Jennifer Lentz — Psychoacoustics- Perception of Normal and Impaired Hearing with Audiology Applications

Yield

569 of 2208 paragraphs kept (25.8%). Target for mining: 30%–50% — ⚠️ BELOW target.

Pre-Assessment

Jennifer Lentz is a Professor of Speech, Language, and Hearing Sciences at Indiana University (Purdue School of Health and Human Sciences), a psychoacoustician who has published extensively on normal and impaired auditory perception, including work on loudness, cochlear implants, and temporal processing. The book title frames it as a survey text explicitly pairing psychoacoustic perception with audiology applications, which is a good sign for your stated purpose.

Given your mining stance and desire for “lists of concepts and theories and models,” this book should yield a high density of established facts (experimental findings on loudness, pitch, masking, temporal/spatial resolution) and structured conceptual frameworks/theories (such as auditory filter models, loudness models like the Moore/Glasberg model, and peripheral vs. central processing distinctions). It will likely be more textbook-concepts than inspiration/speculation — Lentz writes as a researcher-textbook author, so you should expect explanatory models presented with supporting evidence rather than provocative new theories. If you plan to mine it, expect a meaty but conceptually dense read that will reward a structured note-taking approach.

Reading Goal

Prioritizing: Factual Claims (Reader wants to understand actual perception differences, needs concrete facts), Definitional Content (Asks for concepts, theories, and models — definitions are core to this), Causal Relationships (Understanding perception requires cause-effect mechanisms behind hearing), Connection Points (Links between normal/impaired perception and related models are useful), Contrarian or Surprising Claims (Surprising contrasts between normal and impaired hearing are informative) De-prioritizing: Inspiration and Speculation (Reader wants systematic understanding, not speculative ideas)

Thesis

Psychoacoustics explains perception through physiological mechanisms · ch. 0

Argument

1. Auditory perception depends on understanding ear capabilities and hearing loss effects — ch. 0
2. Physiological tests measure sound representation, never the perception itself — ch. 0
3. Successful communication requires multiple distinct auditory perception abilities beyond simple detection. — ch. 0
4. Standard audiological tests miss most of the perceptual abilities humans need to communicate — ch. 0
5. Hearing-impaired perception studies illuminate the mechanisms behind normal hearing — ch. 0
6. The audiogram is a behavioral test rooted in a century of psychoacoustics — ch. 0
7. Topic-based organization beats sequential background chapters for teaching audiology — ch. 0
8. The audiogram measures only detection and conceals varied sensorineural perceptual deficits. — ch. 0
9. Reliable perception measurement emerged only in the early 1800s — ch. 1
10. Psychoacoustics originated in early 1700s experimental psychology — ch. 1
11. Early psychoacoustics lacked tools to control sound intensity independently of frequency — ch. 2
12. The decibel unit enabled standardized hearing characterization — ch. 2
13. Corporate and technical goals, notably telephony, shaped which auditory abilities researchers studied — ch. 2
14. Sensorineural hearing loss compresses the full loudness range into fewer decibels — ch. 2
15. Harvey Fletcher pioneered threshold measurement, loudness relations, and the masking model. — ch. 2
16. Bell Labs research priorities were shaped by telephone engineering needs — ch. 2
17. Early 20th-century hearing research was steered by telephone engineering needs. — ch. 2
18. Modern audiology rests on the premise that perception connects to physics — ch. 2
19. Helmholtz made the first psychoacoustic observations in hearing — ch. 2
20. The 1935 Beasley survey first established US normal-hearing thresholds — ch. 2
21. Fletcher originated threshold measurement, loudness relations, and masking models — ch. 2
22. Hearing loss was first quantified as a percentage of remaining dynamic range — ch. 2
23. Early commercial audiometers cost about $25,000 in modern currency, driving a portable redesign. — ch. 2
24. Audibility thresholds can be expressed on physical or perceptual decibel scales — ch. 2
25. The telephone industry drove development of technologies for measuring hearing. — ch. 2
26. The audiogram’s form was contested because no standard existed for its axes. — ch. 2
27. Harvey Fletcher shaped modern psychoacoustics and audiology at Bell Labs — ch. 2
28. Fechner made conscious perception measurable and founded experimental psychology — ch. 2
29. Earliest hearing-loss tests measured duration and distance of audibility — ch. 2
30. Pitch perception involves both spectral and temporal representations of sound — ch. 2
31. The dynamic range of hearing is largest between 500 and 6000 Hz — ch. 2
32. Psychoacoustics measures detection, discrimination, magnitude, and recognition of sounds — ch. 2
33. The audiogram only captures detection thresholds and fails to predict real-world speech perception — ch. 2
34. Early psychoacoustics neglected loudness because sound intensity could not yet be controlled. — ch. 2
35. Threshold measurement method, not listener differences, caused the 10 dB gap — ch. 2
36. Wundt built drop-based devices isolating intensity from frequency for controlled study. — ch. 2
37. Wundt founded experimental psychology as separate from biology and philosophy — ch. 2
38. Speech intelligibility indexes average signal-to-noise ratio across critical bands — ch. 2
39. Early hearing-loss assessment relied on tuning-fork duration and distance thresholds. — ch. 2
40. A widely used audiometric standard was calibrated roughly 10 dB off — ch. 2
41. Weber’s law states JND is a constant fraction of stimulus magnitude — ch. 2
42. Early audiogram standardization debates concerned level units and axes, not frequency scaling. — ch. 2
43. Bell Labs pursued only hearing questions relevant to telephone engineering. — ch. 2
44. Binaural sound localization depends on ear-level temporal and intensity encoding efficiency — ch. 2
45. The audiogram measures only detection thresholds, so it misses everyday speech-in-noise ability. — ch. 2
46. Pure tones are used for audiometry because they are frequency-specific — ch. 3
47. Absolute threshold is the minimum detectable sound level without external noise — ch. 3
48. Audiograms test pure-tone detection because pure tones are maximally frequency-specific — ch. 3
49. Auditory perception is a four-level hierarchy from detection to comprehension. — ch. 3
50. Lower-level auditory deficits cascade upward but not all higher-level deficits trace downward. — ch. 3
51. Audiometry pure-tone durations are set by perception, not acoustic independence — ch. 4
52. A 1 Pa peak-amplitude tone produces 91 dB SPL — ch. 4
53. Short sound durations necessarily produce broad frequency bandwidths. — ch. 4
54. A pure tone’s peak amplitude is the maximum pressure it achieves per cycle. — ch. 4
55. Shorter sounds necessarily have broader spectral bandwidths — ch. 4
56. Outer and middle ear structures provide frequency-specific amplification of incoming sound — ch. 4
57. ASHA prescribes 1-2 second steady and 200-ms pulsed tones for audiometry — ch. 4
58. Short tones smear extra frequencies into their spectra, a cost called spectral splatter. — ch. 4
59. Combined outer and middle ear amplification spans roughly 600 to 4000 Hz — ch. 4
60. Longer pure-tone durations produce narrower spectral peaks with less splatter — ch. 4
61. Middle ear stiffness reduces low-frequency gain while added mass reduces high-frequency gain — ch. 4
62. The ear analyzes frequencies by location along the basilar membrane. — ch. 4
63. Time and frequency representations are linked so short durations broaden bandwidth — ch. 4
64. Peak amplitude misrepresents complex sounds with varying amplitude — ch. 4
65. The mid-frequency hearing advantage explains why alarms and speech amplification target 1000-6000 Hz. — ch. 5
66. Hearing thresholds were first systematically mapped in the 1930s using two distinct measurement paradigms — ch. 5
67. 95 percent of auditory nerve fibers carry coded signals from inner hair cells upward — ch. 5
68. High spontaneous-rate fibers have low thresholds while low SR fibers have high thresholds. — ch. 5
69. Two-ear listening improves sound-field thresholds by 10 to 15 dB — ch. 5
70. Hearing depends on sequential physiological stages, each with distinct perceptual consequences when damaged. — ch. 5
71. Outer hair cell loss reduces hearing sensitivity by up to 60 dB — ch. 5
72. Outer hair cells respond better than inner hair cells to low-frequency sound — ch. 5
73. Auditory nerve fibers divide into three types by spontaneous firing rate. — ch. 5
74. Live cochleas are much more sharply tuned than cadaver measurements suggested — ch. 5
75. Auditory nerve fibers’ thresholds correlate inversely with their spontaneous firing rates. — ch. 5
76. Individual auditory nerve fibers cannot code the full hearing dynamic range — ch. 5
77. Forced-choice paradigms present one signal amid two or more observation intervals. — ch. 6
78. A full clinical audiogram can be collected in about fifteen minutes. — ch. 6
79. Adaptive procedures converge on thresholds without explicit psychometric functions — ch. 6
80. Signal detection theory models signals and noise as two probability distributions — ch. 6
81. In signal detection theory, threshold responses depend on an internal response criterion reflecting bias. — ch. 6
82. An unusually low false positive rate signals a patient exaggerating hearing loss — ch. 6
83. Free-field hearing thresholds can exceed headphone thresholds by over 15 dB — ch. 6
84. Self-adjustment threshold methods are fast but lack a standardized response criterion across listeners. — ch. 6
85. Constant-stimuli threshold measurement is time consuming because many trials are needed per level. — ch. 6
86. Clinical threshold changes are measured relative to normative curves, not in absolute dB SPL — ch. 6
87. Forced-choice testing cancels listener response criterion effects in threshold estimation — ch. 6
88. Response bias distorts threshold measurements in hearing experiments. — ch. 6
89. Noise can damage high-threshold auditory fibers while audiograms still look normal — ch. 6
90. Hearing loss does not change the psychometric function’s 12-dB detection range — ch. 6
91. Response bias can contaminate any psychophysical threshold estimate — ch. 6
92. Thresholds are statistical detection probabilities, not absolute cutoffs — ch. 6
93. Hearing-loss severity categories lead patients to underestimate their communication difficulties — ch. 6
94. Threshold from up-down staircases is the averaged level at response reversals. — ch. 6
95. Damage location in the ear maps onto specific frequency regions of hearing loss. — ch. 6
96. Exaggerated hearing loss appears as an overly conservative response bias during audiometry — ch. 6
97. The outer and middle ear, not the cochlea, shape the absolute threshold curve. — ch. 6
98. Damage to high-threshold auditory nerve fibers can escape threshold detection yet impair speech-in-noise perception. — ch. 6
99. Adaptive staircases track a listener’s responses to set signal level — ch. 6
100. Undefined observation intervals prevent patients from anticipating signals and biasing thresholds low — ch. 6
101. Research staircase methods require start level, step, and stop criteria — ch. 6
102. The method of limits estimates thresholds by averaging ascending and descending detection levels — ch. 6
103. The shape of the audiogram reflects outer and middle ear transfer, not cochlear transmission — ch. 6
104. Staircase rules specify how many correct trials precede a level decrease — ch. 6
105. The method of constant stimuli needs prior knowledge of testable levels — ch. 6
106. Patient false positives signal a reasonable response criterion, not poor performance — ch. 6
107. Smaller step sizes in audiometry detect feigned hearing loss — ch. 6
108. The audiogram’s inverted axis breaks standard scientific plotting convention — ch. 6
109. Clinical threshold testing uses undefined observation intervals to prevent anticipation from lowering thresholds. — ch. 6
110. Early otosclerosis adds stiffness and thus selectively reduces low-frequency hearing — ch. 6
111. Middle-ear stiffness increases cause low-frequency hearing loss — ch. 6
112. Standard clinical threshold testing estimates the 85-95% detection point — ch. 6
113. Both conductive and sensorineural damage drastically alters absolute threshold curves. — ch. 6
114. Some false positives during threshold testing indicate healthy response bias — ch. 6
115. Threshold estimates reflect both ear sensitivity and listener response bias — ch. 6
116. Ossicular mass increases from otosclerosis cause high-frequency hearing loss — ch. 6
117. Psychometric functions map continuous stimulus scales onto probabilistic detection judgements — ch. 6
118. Masking occurs when one sound interferes with perceiving another — ch. 7
119. Energetic and informational masking operate through distinct peripheral and central mechanisms — ch. 7
120. White noise amplitude is described by total power or spectrum level (LPC). — ch. 7
121. Noise is defined relationally against the signal rather than acoustically — ch. 7
122. Filter cutoff frequency is conventionally the 3-dB-down point. — ch. 7
123. Healthy ears exploit gaps in fluctuating maskers better than steady ones — ch. 7
124. White noise carries constant power per hertz across the human hearing range — ch. 7
125. A filter’s transfer function describes gain in dB independent of sound level. — ch. 7
126. Narrowband noise needs bandwidth and center frequency descriptors — ch. 7
127. Masking depends on acoustic relationships between masker and signal, not on subjective noise. — ch. 7
128. Hearing loss acts like a filter attenuating specific frequencies — ch. 7
129. White noise has flat power across the 20 to 20,000 Hz hearing range — ch. 7
130. Two noises with equal LPC differ in total power by their bandwidth — ch. 7
131. Masking experiments revealed the auditory filter underlying frequency selectivity — ch. 7
132. The excitation pattern is the internal representation of a stimulus spectrum — ch. 7
133. A masker’s intensity, frequency content, and temporal pattern determine its masking capability. — ch. 8
134. Frequency selectivity is the auditory system’s ability to represent one frequency independently of another. — ch. 8
135. Three acoustic properties determine whether a sound masks another. — ch. 8
136. Masking experiments infer auditory representation from masker effects on signals. — ch. 8
137. Early cochlear measurements were distorted by post-mortem damage — ch. 8
138. Broadband maskers at low levels mask mid frequencies more than extremes. — ch. 8
139. Hawkins and Stevens measured broadband-noise masking of pure tones across eight masker levels. — ch. 8
140. Conductive hearing loss can be modeled as a filter, but sensorineural loss cannot — ch. 8
141. Masking is quantified as the threshold shift between unmasked and masked conditions. — ch. 8
142. A masker masks most when its frequency matches the signal frequency — ch. 8
143. Masking patterns reveal the ear’s internal psychological representation of a sound. — ch. 8
144. Band-pass filters are specified by either two cutoffs or center frequency plus bandwidth — ch. 8
145. Beyond threshold, masker and signal levels rise one-for-one in decibels — ch. 8
146. Masking effectiveness depends on masker-signal power, frequency, and timing relationships — ch. 8
147. Tuning curves map the lowest level that evokes neural or basilar response — ch. 8
148. Similar frequencies mask each other by competing for the same cochlear location. — ch. 8
149. Amount of masking is expressed as a decibel difference, not an absolute SPL level — ch. 8
150. Basilar membrane tuning is sharper in living than dead cochleae — ch. 8
151. The notched-noise method directly measures auditory filter shape. — ch. 9
152. Low-frequency maskers mask high-frequency signals more than the reverse, and this worsens with intensity. — ch. 9
153. The excitation pattern plots auditory-filter output power against filter center frequency — ch. 9
154. Excitation patterns smooth the spectrum, blurring harmonic and formant detail the acoustic signal carries — ch. 9
155. There is a critical bandwidth beyond which adding noise power no longer increases masking — ch. 9
156. The basilar membrane’s logarithmic spacing justifies plotting auditory representations on log frequency axes — ch. 9
157. The ear’s frequency selectivity is imperfect and worsens at higher frequencies — ch. 9
158. A narrow noise band can mask signals multiple octaves away at high stimulus levels. — ch. 9
159. The ear’s frequency selectivity worsens as frequency rises above 500 Hz. — ch. 9
160. The band-widening paradigm measures signal threshold while varying masker bandwidth — ch. 9
161. Masking effectiveness depends only on masker power inside the critical band. — ch. 9
162. ERB is the standard metric for auditory filter bandwidth — ch. 9
163. Only low-numbered harmonics are resolved, higher ones blur together in the internal representation — ch. 9
164. Only masker power within the critical band around a signal affects its threshold — ch. 9
165. The ear’s frequency resolution worsens progressively at higher frequencies. — ch. 10
166. Identifying a vowel requires at least two of its formants — ch. 11
167. Wider auditory filters admit excess noise that fully obscures high-frequency formants — ch. 11
168. Simultaneous-masked PTCs are broader than forward-masked PTCs, with similar overall shape — ch. 11
169. Simultaneous masking yields broader tuning curves than forward masking. — ch. 11
170. Listeners use distributed spectral information but not all of it — ch. 11
171. Widening modulated-noise bandwidth can paradoxically lower detection thresholds. — ch. 11
172. Impaired frequency selectivity, suppression, and fluctuation use jointly degrade hearing — ch. 11
173. Normal-hearing listeners exploit temporal dips in fluctuating maskers to detect signals. — ch. 11
174. Clinical maskers must be wider than the critical band to work — ch. 11
175. Impaired frequency selectivity and lost suppression increase masking and reduce spectral contrasts — ch. 11
176. Forward masking reveals an effect that only appears when sounds co-occur. — ch. 11
177. Fluctuating maskers produce masking release that Fletcher’s power spectrum model cannot explain. — ch. 11
178. Simultaneous-masking filters may understate the ear’s true spectral resolution — ch. 11
179. Psychophysical tuning curves measure frequency selectivity via tone-on-tone masking. — ch. 11
180. A masker only shifts thresholds that already lie below its EML. — ch. 11
181. Listeners benefit from spectral profiles bandwidth-wide yet do not use all available spectral information — ch. 11
182. Two-tone suppression makes simultaneous masking appear broader than forward masking — ch. 11
183. Reduced frequency selectivity hurts speech perception less than reduced audibility does — ch. 11
184. Cross-hearing via bone conduction can contaminate thresholds, requiring masking in audiometry. — ch. 11
185. Masking by bandlimited noise depends only on masker energy within the critical band. — ch. 11
186. Spectral valleys contribute little to vowel identification compared with formants — ch. 11
187. Masking release from modulated noise also improves speech perception. — ch. 11
188. Loss of cochlear suppression explains similar PTCs across masking conditions. — ch. 11
189. Cochlear damage increases susceptibility to masking, hurting speech in noise. — ch. 11
190. Hearing loss impairs frequency selectivity beyond what stimulus level differences explain. — ch. 11
191. Sensorineural hearing loss worsens masking beyond mere threshold elevation — ch. 11
192. A worked dB EML example shows masking calculations in practice. — ch. 11
193. Absence of recruitment in sensorineural loss signals retrocochlear pathology. — ch. 12
194. Loudness coding requires pooled responses across many auditory nerve fibers — ch. 12
195. A tone and wideband noise of very different levels can equally sound loud — ch. 12
196. A sound’s softness is only meaningful relative to who can hear it — ch. 12
197. Fletcher and Munson’s 1933 loudness data remain essentially accurate today. — ch. 12
198. The full loudness range squeezes into a smaller dynamic range for impaired listeners. — ch. 12
199. A-weighted decibels better predict hearing damage than unweighted sound pressure level. — ch. 12
200. Hyperacusis is a separate pathology from sensorineural hearing loss — ch. 12
201. Gustav Fechner mathematically formulated the law named after his mentor Weber. — ch. 12
202. Loudness cannot be explained by single auditory nerve fiber firing alone — ch. 12
203. Stevens defined one sone as a 40 dB SPL 1000-Hz tone — ch. 12
204. Wider bandwidth increases perceived loudness at equal sound pressure — ch. 12
205. Humans discriminate level differences of under half a decibel across a 100 dB range — ch. 12
206. Categorical loudness scaling measures uncomfortable and comfortable loudness levels using verbal categories — ch. 12
207. Sound pressure and intensity are distinct quantities interconvertible by a known relationship — ch. 12
208. Weber’s law holds for noise intensity discrimination above about 20 dB SL — ch. 12
209. The auditory system’s ~120 dB dynamic range exceeds any single nerve fiber’s coding capacity — ch. 12
210. A sound’s bandwidth independently affects how loud it sounds. — ch. 12
211. Pure-tone Weber functions slope downward across all tested frequencies — ch. 12
212. Reaction time measures loudness across the full hearing range — ch. 12
213. Fiber-type-specific damage produces distinct loudness perception abnormalities. — ch. 12
214. Loudness grows faster at low levels than Stevens’ power law predicts — ch. 12
215. Reaction time spans the full hearing range where psychometric functions cover only 10-15 dB — ch. 12
216. Outer and middle ear damage changes the loudness frequency balance — ch. 12
217. Hearing-impaired listeners show faster loudness growth but similar discomfort thresholds — ch. 12
218. Sound level meters measure pressure, from which intensity is derived — ch. 12
219. Intensity is directly quantifiable acoustically while loudness requires human listeners — ch. 12
220. Categorical loudness scaling uses labeled bars from Not Heard to Too Loud — ch. 12
221. Sensorineural hearing loss causes abnormal rapid loudness growth called recruitment — ch. 12
222. Wide bandwidth noise sounds as loud as a narrower tone despite lower level — ch. 12
223. Severe hearing loss from inner hair cell loss reduces maximum loudness — ch. 12
224. Near-threshold sounds may sound louder to impaired than to normal ears — ch. 12
225. Excitation pattern differences grow with filter frequency, favoring the high-frequency edge — ch. 12
226. Recruitment can explain why loudness summation is absent in noise-induced hearing loss — ch. 12
227. Reaction time measures loudness in animals and language-disabled people — ch. 12
228. Noise intensity discrimination improves by pooling multiple frequency regions — ch. 12
229. Graph scaling choices shape the inferred form of loudness functions. — ch. 12
230. The phon scale defines loudness relative to equal-loudness matches at 1 kHz — ch. 12
231. Larger baseline weights require proportionally larger differences to be noticed — ch. 12
232. Loudness grows as a power law of intensity, not linearly. — ch. 12
233. Loudness models estimate total neural activity since it cannot be measured directly — ch. 12
234. Intensity discrimination measures the smallest detectable change in loudness — ch. 12
235. Outer hair cell damage steepens the basilar membrane’s growth function — ch. 12
236. Miller’s 1947 study tested Weber’s law with noise stimuli — ch. 12
237. Higher-frequency auditory filters carry more intensity-difference information than the signal-centered filter — ch. 12
238. No single standard metric describes auditory intensity discrimination — ch. 12
239. A 10 dB increase always doubles perceived loudness above 40 dB — ch. 12
240. The loudness-intensity relationship is named Stevens’ power law. — ch. 12
241. Loudness discomfort levels are measured to fit hearing aids and assess hyperacusis — ch. 12
242. Weber fractions in audition are computed from intensity, not decibels — ch. 12
243. Magnitude estimation lets listeners assign numbers proportional to perceived loudness. — ch. 12
244. Just noticeable differences are proportional to baseline stimulus size — ch. 12
245. Loudness balancing measures loudness by matching a test sound’s level to a reference — ch. 12
246. The term UCL fits the measurement better than LDL, yet US practice favors LDL — ch. 12
247. Clinical LDL testing uses categorized loudness scaling with ascending stepped levels — ch. 12
248. Loudness is not reducible to sound pressure level or signal power — ch. 12
249. Loudness is a psychological percept measurable only through human report — ch. 12
250. Outer hair cell loss is the primary driver of loudness recruitment — ch. 12
251. Different auditory nerve fiber types have distinct response thresholds. — ch. 12
252. Mild-moderate losses show recruitment while severe-profound losses show underrecruitment — ch. 12
253. Stevens had to invent both the tools and the unit for measuring loudness — ch. 12
254. Loudness models can guide hearing aid programming and alarm design — ch. 12
255. Stevens anchored the sone unit to a 1000-Hz tone at 40 dB SPL. — ch. 12
256. Loudness as perception can never be directly measured physiologically — ch. 12
257. Loudness is measured either by rating magnitude or by matching equal loudness — ch. 12
258. The near miss to Weber’s law results from the ear using spread-of-excitation across frequency — ch. 12
259. Near miss to Weber’s law occurs for tones but not noise — ch. 12
260. Central auditory processing across frequencies produces the near miss — ch. 12
261. Weber fraction for tones is level but not frequency dependent — ch. 12
262. ‘Sound level’ is a deliberately vague unit-free term for sound size — ch. 12
263. Basilar membrane vibration can be measured in vivo by tracking a bead’s movement — ch. 12
264. Magnitude estimation of loudness yields only relative, not absolute, values. — ch. 12
265. Intensity discrimination improves with level for tones, violating Weber’s law — ch. 12
266. Sounds are time-varying when their intensity changes over time — ch. 13
267. Brief quiet gaps in sounds can introduce spectral cues that contaminate gap detection results — ch. 13
268. Temporal fine structure is vital yet not perceived as a temporal event — ch. 13
269. Gap detection measures the smallest audible silent gap — ch. 13
270. White noise is not a valid stimulus to assess gap perception. — ch. 13
271. Temporal processing deficits undermine speech understanding and music appreciation — ch. 13
272. A sound must decay enough before a following sound stops fusing with it — ch. 13
273. Gap detection thresholds improve with increasing stimulus bandwidth but not frequency region — ch. 13
274. Temporal processing is essential for hearing speech and music — ch. 13
275. Gap added to a tone creates audible spectral splatter or side lobes. — ch. 13
276. Inserting a temporal gap into a stimulus produces spectral splatter at the gap edges — ch. 13
277. Auditory stimuli separate into fine structure and slower envelope — ch. 13
278. Gap detection acuity improves with presentation level up to about 30 dB SL. — ch. 14
279. Elevated gap detection thresholds in hearing loss stem from threshold elevation, not temporal pathology — ch. 14
280. The ear integrates energy over time to lower detection thresholds for longer sounds — ch. 16
281. Modulation depth m ranges from unmodulated to fully modulated sounds — ch. 16
282. Narrowband noises contain fewer frequencies and show greater amplitude fluctuations than broadband noise. — ch. 16
283. Amplitude-modulated sounds split into slow-varying envelope and fast-varying fine structure — ch. 16
284. Slow release from forward masking impairs comprehension of rapid speech. — ch. 16
285. Gap detection offers quick but shallow measures of temporal acuity — ch. 16
286. Forward masking reveals how the ear’s perceptual representation of sound decays over time — ch. 16
287. Wide bandwidth improves temporal perception while low-pass filtering limits it — ch. 16
288. Narrowband noise’s natural waveform fluctuations mask the presence of inserted gaps — ch. 16
289. Wider stimulus bandwidth improves the ear’s temporal acuity — ch. 16
290. Narrower noise bandwidths produce slower amplitude fluctuation rates — ch. 16
291. Temporal order thresholds exceed gap detection because listeners must hold sound identities in memory — ch. 16
292. Temporal modulation detection is independent of hearing threshold — ch. 16
293. The auditory system represents modulations below 55 Hz well and worse above — ch. 16
294. Gap detection measures only on-off sensitivity, not coding of fluctuation rates. — ch. 16
295. Soft sounds give the ear inadequate access to rapid amplitude changes in speech — ch. 16
296. Gap detection tasks measure how the ear follows temporal changes relevant to communication — ch. 16
297. Hearing loss reduces audibility and restricts usable bandwidth for temporal processing — ch. 16
298. Intense forward maskers produce both more masking and more release — ch. 16
299. Narrowband noises fluctuate more than wideband stimuli, making them useful for studying fluctuation coding — ch. 16
300. Narrow-band devices like telephones degrade temporal cue coding and raise listening effort — ch. 16
301. Amplitude modulation below about 60 Hz is well represented in hearing — ch. 16
302. Temporal modulation transfer functions trade completeness against measuring time — ch. 16
303. Gap detection experiments vary in whether listeners report a gap or count of sounds — ch. 16
304. Forward masking requires maskers with similar frequency components and high intensity — ch. 16
305. Stimulus fluctuations hurt gap detection but aid speech perception elsewhere — ch. 16
306. Gap detection improves with bandwidth because the ear listens across more auditory filters — ch. 16
307. High modulation detection thresholds signal poor temporal representation of those rates. — ch. 16
308. The auditory system can discard uninformative temporal information during detection — ch. 17
309. Sensorineural hearing loss disrupts some temporal abilities but not others, with wide individual variability — ch. 17
310. Listeners with hearing loss form a heterogeneous perceptual group, not a single category — ch. 17
311. Hearing-impaired ears can outperform normal ears at amplitude modulation detection — ch. 17
312. Outer hair cell damage removes cochlear compressive nonlinearity — ch. 17
313. Similar critical durations do not imply normal temporal integration — ch. 17
314. Presenting speech at the same loudness minimizes forward-masking differences — ch. 17
315. Two separated tone pulses aid detection more than one, unaffected by intervening noise level — ch. 17
316. Temporal integration models divide on time constant assumptions of hundreds versus single-digit milliseconds. — ch. 17
317. The energy detector model fails because it accumulates interfering noise along with signal energy. — ch. 17
318. The audiogram cannot predict which hearing-impaired listeners have temporal processing deficits — ch. 17
319. Hearing-impaired listeners gain half or less benefit from longer stimulus durations — ch. 17
320. Forward masking decay slows markedly after masker offset in hearing loss — ch. 17
321. Sensorineural hearing loss reduces temporal integration benefit by half or more — ch. 17
322. Prolonged forward masking makes vowels mask consonants in impaired ears — ch. 17
323. Auditory integration over time may involve intelligent selection of informative samples — ch. 17
324. Comparing hearing-impaired and normal listeners requires controlling for both sensation level and absolute level — ch. 17
325. Gap detection and amplitude modulation are usually intact after sensorineural loss — ch. 17
326. Sensory neural hearing loss preserves temporal resolution when audibility is compensated — ch. 18
327. Temporal processing of sound has three distinct measurable categories. — ch. 18
328. Hearing loss extends internal masker persistence and shrinks duration benefits — ch. 18
329. Pitch lacks a magnitude dimension, complicating its subjective measurement — ch. 19
330. Period histograms visualize neural firing synchrony by spike phase — ch. 19
331. Helmholtz’s place theory says pitch derives from the basilar membrane’s location of maximum excitation. — ch. 19
332. Pitch arises from where along the cochlea a sound maximally stimulates — ch. 19
333. Fundamental frequency is coded dually via harmonics and envelope rate — ch. 19
334. Removing low harmonics from a complex tone leaves its pitch unchanged. — ch. 19
335. Place coding poorly carries pitch when harmonics go unresolved. — ch. 19
336. Physiological coding of frequency does not by itself explain perceived pitch. — ch. 19
337. Pitch is formally defined as where sounds fall on a musical scale — ch. 19
338. Helmholtz’s place theory failed to explain all pitch phenomena, prompting more complex models. — ch. 19
339. The auditory system can extract pitch from resolved low-frequency harmonics using place patterns — ch. 19
340. Pooled neural firing encodes stimulus period as spike intervals. — ch. 19
341. Not all sounds have a pitch even though all have frequency content — ch. 19
342. Auditory frequency is encoded by both place and temporal codes. — ch. 19
343. Pure-tone temporal coding is low-frequency only, but complex tones use both fiber types. — ch. 19
344. Harmonic amplitudes shape timbre and loudness but not pitch. — ch. 19
345. Pitch can be derived from harmonic spacing even without the fundamental present. — ch. 19
346. Harmonic tones are integer multiples of a fundamental frequency — ch. 19
347. Sounds missing many harmonics still evoke a weak pitch sensation — ch. 20
348. Fundamental frequency differences between voices improve speech intelligibility — ch. 20
349. Resolved harmonics use place pitch coding while unresolved harmonics use temporal coding — ch. 20
350. Increasing intensity improves frequency discrimination, much more at low frequencies — ch. 20
351. At 1000 Hz humans detect frequency changes of about 0.2 percent — ch. 20
352. Level-dependent frequency discrimination contradicts a purely temporal pitch code — ch. 20
353. The mel scale defines pitch by assigning 1000 mels to a 1000-Hz tone — ch. 20
354. Removing harmonics degrades f0 discrimination but it stays precise without them — ch. 20
355. Voice differences include formant and temporal cues beyond fundamental frequency — ch. 20
356. Sensorineural hearing loss worsens diplacusis, which even normal hearers have mildly — ch. 20
357. Place and temporal codes each offer distinct neural mechanisms for extracting pitch — ch. 20
358. FDL findings compromise a purely temporal account of low-frequency pitch. — ch. 20
359. Random intensity variation disrupts place but not temporal pitch coding — ch. 20
360. Modern pitch research relies on discrimination tasks because subjective pitch ratings are problematic — ch. 20
361. Resolved low-numbered harmonics are required to encode pitch by place — ch. 20
362. Same-sex background voices mask speech for listeners of either sex. — ch. 20
363. The residue pitch refuted Helmholtz’s place theory of pitch percept. — ch. 20
364. Pitch is coded by different mechanisms above and below roughly 3 kHz — ch. 20
365. Physiological measures alone cannot prove how pitch perception works — ch. 20
366. Listeners identify melodies perfectly using only temporal information because amplitude-modulated noise can encode pitch — ch. 20
367. Stevens measured pitch shifts of up to 15-20% with changing intensity. — ch. 20
368. Hearing impairment disrupts both place and temporal pitch codes — ch. 20
369. Pitch cannot be measured absolutely, only relative to another tone — ch. 20
370. Pitch may be jointly coded by temporal patterns and their cochlear location — ch. 20
371. Hearing-impaired frequency discrimination does not correlate with audiogram or frequency selectivity — ch. 20
372. The Weber fraction for frequency declines below 1500 Hz then rises above 2000 Hz — ch. 20
373. Both place and temporal codes could underlie pitch, confounding identification of the main code — ch. 20
374. Pitch strength is a distinct perceptual dimension absent from loudness — ch. 20
375. The frequency-pitch mapping was established before models of pitch existed — ch. 20
376. Sensorineural hearing loss damages pitch, harming speech-in-noise communication — ch. 20
377. Hearing-impaired listeners usually hear the correct pitch but with more variability — ch. 20
378. The existence region supports a place-based harmonic template model of pitch — ch. 20
379. Temporal codes yield weak pitches compared to place codes — ch. 20
380. Individual hearing-impaired listeners compensate by relying on whichever pitch code remains intact — ch. 20
381. Audiograms and frequency selectivity fail to predict pitch perception deficits — ch. 20
382. Reported pitch-with-intensity shifts vary widely with method — ch. 20
383. Absolute frequency discrimination worsens as reference frequency increases — ch. 20
384. Pitch has no magnitude like loudness, so magnitude scaling misapplies to it. — ch. 20
385. Simultaneous synthetic vowels can be separated by their fundamental frequencies alone. — ch. 20
386. Across-filter neural synchrony provides a robust pitch code — ch. 20
387. Pitch of harmonic sounds is determined by the fundamental frequency. — ch. 20
388. Pitch shifts with intensity but individual listener variability is large. — ch. 20
389. Melodic interval identification degrades once about 9-10 harmonics are removed — ch. 20
390. Place code governs pitch perception of pure tones above about 4 to 5 kHz — ch. 20
391. Hearing loss disrupts pitch via place, temporal, and interaural mechanisms. — ch. 20
392. Auditory nerve phase locking can encode slow waveform fluctuations across filters — ch. 20
393. Raising intensity lowers pitch at low frequencies but raises it at high frequencies. — ch. 20
394. Missing fundamental pitch survives even when cochlear distortion is masked out — ch. 20
395. Pitch enables voice identification and the cocktail party listening effect — ch. 20
396. Hearing loss disrupts pitch perception through multiple independent coding failures — ch. 20
397. Experiments isolating two-ear advantages must present stimuli over headphones — ch. 21
398. Ear separation on one axis makes horizontal binaural cues strongest — ch. 21
399. High-frequency tones produce ambiguous azimuthal localization due to phase wrapping. — ch. 21
400. Head shadow attenuates sound arriving at the far ear unless the source is centered — ch. 21
401. The lateral superior olive compares ear intensities via excitation and inhibition — ch. 21
402. Small detection-threshold gains amplify into much larger identification-level changes — ch. 21
403. Two ears give small but consistent gains across all auditory tasks — ch. 21
404. Interaural phase difference varies with frequency while interaural time difference does not — ch. 21
405. Interaural level differences grow with frequency and side placement — ch. 21
406. High-frequency tones yield multiple possible source locations from a single phase difference — ch. 21
407. High-frequency sounds reflect off the head while low-frequency sounds diffract around it — ch. 21
408. All sound locations sharing one ITD form an infinite cone of confusion — ch. 21
409. Sound’s wavelength determines whether it reflects off the head or diffracts around it — ch. 21
410. ITDs are frequency-independent physically yet frequency-dependent perceptually. — ch. 21
411. Interaural level differences grow with frequency and reach up to 20 dB. — ch. 21
412. Headphone experiments measure binaural summation by stimulating each ear independently — ch. 21
413. Sound location is mapped with azimuth and elevation coordinates — ch. 21
414. Binaural summation gives a consistent two-ears vs one-ear benefit — ch. 21
415. The cone of confusion prevents up-down and front-back sound discrimination — ch. 21
416. Rayleigh first proposed ILDs code high frequencies and ITDs code low frequencies — ch. 21
417. Head movements and pinna shape resolve ambiguous sound localization — ch. 21
418. Frontal minimum audible angle is about one degree for low frequencies — ch. 22
419. Sound localization is most accurate when facing the sound source — ch. 22
420. The just-detectable speaker shift defines the minimum audible angle. — ch. 22
421. Antiphasic speech improves word identification by 20 percentage points at low SNRs. — ch. 24
422. The auditory system lacks robust access to interaural phase above 1000 Hz — ch. 24
423. Pinna cues drive the need for individualized HRTFs in vertical localization — ch. 24
424. Horizontal-plane localization needs no listener-specific HRTF, but vertical does — ch. 24
425. Head-related transfer functions encode all body-induced spectral and temporal sound changes — ch. 24
426. Separating signal from masker locations improves detection through two binaural effects — ch. 24
427. The first arriving sound wave dominates perceived localization regardless of level — ch. 24
428. An 8 dB better-ear advantage can raise word identification by 56 percentage points — ch. 24
429. Headphones allow separating interaural phase from interaural time delay — ch. 24
430. Adding correlated noise across ears can improve rather than worsen monaural detection — ch. 24
431. Pinnae shape the sound spectrum to encode elevation and front-back position — ch. 24
432. Complex sounds allow envelope time-difference coding at high frequencies — ch. 24
433. The better-ear advantage alone yields an 8 dB SRT benefit worth 56 percentage points — ch. 24
434. Inverting signal phase at one ear vastly releases speech from masking. — ch. 24
435. Interaural phase discrimination is finest at midline and low frequencies — ch. 24
436. Headphone experiments reveal auditory abilities that free-field studies cannot expose. — ch. 24
437. Head shadow gives one ear a better signal-to-noise ratio in typical listening — ch. 24
438. Headphone studies reveal ILD perception abilities hidden by natural field acoustics — ch. 24
439. Speech understanding benefits when the signal is phase-inverted at one ear. — ch. 24
440. Interaural noise correlation inversely drives the magnitude of binaural release from masking. — ch. 24
441. Separating a signal from a competing noise location aids detection beyond diotic summation — ch. 24
442. A 5-dB hearing asymmetry doubles the perceived interaural level difference — ch. 25
443. Three distinct perceptual phenomena define the precedence effect. — ch. 25
444. Hearing-impaired listeners gain far less binaural-squelch advantage than normal hearers — ch. 25
445. Cochlear damage disrupts temporal fine structure needed by the MSO — ch. 25
446. Sensorineural hearing loss causes wide variability in sound localization ability — ch. 25
447. Low sensation level impairs ITD and ILD discrimination even in normal listeners — ch. 25
448. Asymmetrical-hearing-loss listeners must physically reposition to exploit their better ear — ch. 25
449. Two ears yield summation, localization, and echo suppression jointly — ch. 25
450. Even small hearing asymmetries across ears disrupt binaural hearing. — ch. 25
451. Two ears improve detection, localization, and masking resistance over one. — ch. 25
452. Hearing loss correlates weakly with precedence-effect echo thresholds. — ch. 25
453. Echo-fusion thresholds vary widely among hearing-impaired listeners regardless of audiometric thresholds. — ch. 25
454. Hearing-impaired listeners benefit roughly two-thirds less from binaural squelch than normal-hearing listeners. — ch. 25
455. Hearing aids cannot restore sound localization because coding damage, not audibility, is the cause — ch. 25
456. Degraded interaural timing coding, not audiometric asymmetry, explains reduced MLD in hearing loss. — ch. 25
457. Restoring audibility does not restore sound localization in hearing loss — ch. 25
458. Amplification cannot restore sound localization impaired by binaural encoding loss. — ch. 25
459. The precedence effect reduces masking from reflections in rooms — ch. 25
460. Head shadow makes high-frequency binaural cues inaudible in sloping hearing loss — ch. 25
461. Binaural summation largely survives sensorineural hearing loss when sounds stay audible — ch. 25
462. Whether loudness recruitment degrades speech perception remains unsettled — ch. 26
463. Amplification only compensates for elevated thresholds, not other perceptual deficits from hearing loss. — ch. 26
464. Frequency selectivity in normal-hearing listeners worsens at high sound levels — ch. 26
465. The choice of hearing aid prescriptive rule barely affects speech intelligibility. — ch. 26
466. Speech intelligibility depends on which frequency bands matter for specific materials. — ch. 26
467. Tinnitus is the top service-connected military disability yet lacks any diagnostic test. — ch. 26
468. Tinnitus pitch spans the entire region of hearing loss, not a single frequency — ch. 26
469. ABLB laddergram rung divergence reveals whether loudness grows faster in an impaired ear — ch. 26
470. Independent compression in each ear distorts binaural localization cues — ch. 26
471. Nonlinear hearing aid amplification partially restores distorted loudness perception. — ch. 26
472. Tinnitus loudness matches do not predict tinnitus annoyance or diagnostic value — ch. 26
473. Loudness recruitment makes raised speech feel too loud even without abnormal sound perception — ch. 26
474. Deficits at lower perceptual levels propagate upward through Erber’s hearing hierarchy — ch. 26
475. Pitch perception deficits from hearing loss impair speech segregation from noise. — ch. 26
476. Hearing aid algorithms distort auditory cues yet still improve speech understanding — ch. 26
477. Directional hearing-aid microphones improve speech-in-noise SNR by over 7 dB. — ch. 26
478. Tinnitus has no objective diagnostic test and is diagnosed by self-report alone — ch. 26
479. Binaural sound lateralizes to the ear receiving the louder signal — ch. 26
480. Hearing loss reduces the effect of inherent noise fluctuations on speech masking. — ch. 26
481. Tinnitus loudness matches fall 5 to 15 dB above audiometric threshold — ch. 26
482. WDRC processing distorts the temporal cues hearing-impaired listeners rely on for stop consonants — ch. 26
483. Signal Detection Theory principles help audiologists extract true thresholds from feigning patients — ch. 26
484. Behavioral psychoacoustics tests detect retrocochlear pathology poorly but rule out healthy ears well — ch. 26
485. Hearing aids address three deficits but leave frequency, temporal, and pitch processing unaddressed. — ch. 26
486. Audibility deficits must be corrected before supra-threshold factors can be studied. — ch. 26
487. Re-instructing suspected feigners shifts their decision criterion toward true thresholds — ch. 26
488. Pitch cues convey identity, intonation, and emotion beyond mere speech content — ch. 26
489. Alternate binaural loudness balancing plots recruitment as non-parallel laddergram rungs — ch. 26
490. Compression hearing aids distort spectral temporal and binaural cues in poorly understood ways — ch. 26
491. Zero false positives during threshold testing signals feigned hearing loss — ch. 26
492. Low-level auditory deficits cascade upward to impair speech comprehension — ch. 26
493. Even slight hearing losses of 16-25 dB HL may benefit from hearing aids. — ch. 26
494. Processing spectral peaks and valleys in separate compression channels erases their level difference — ch. 26
495. Rollover signs make loud amplification harmful to retrocochlear patients — ch. 26
496. Elevated hearing thresholds degrade speech perception by rendering key cues inaudible — ch. 26
497. Hearing-impaired listeners show intact gap detection but prolonged forward masking that hides consonants — ch. 26
498. Auditory processing disorder is a contested diagnosis lacking a single-locus definition — ch. 26
499. Raising speech level reduces the advantage from masker fluctuation absence — ch. 26
500. Hearing loss is a sensory-representation deficit, not merely an acoustic one. — ch. 26
501. Directional hearing aid microphones can degrade sound localization by attenuating lateral sounds — ch. 26
502. Audiology is rooted in psychoacoustics and remains founded on it — ch. 26
503. More hearing aid compression channels measurably degrade vowel perception in hearing-impaired listeners. — ch. 26
504. Precision medicine may soon tailor treatment to individual perceptual disorder profiles — ch. 26
505. Contralateral interference reveals true thresholds about 15-20 dB below the interference level — ch. 26
506. Word recognition that declines with louder speech signals retrocochlear pathology. — ch. 26
507. A 1 dB SNR improvement boosts intelligibility by 7 to 19 percent — ch. 26
508. A 1 dB SNR improvement raises speech intelligibility by 7 to 19 percent. — ch. 26
509. Small amounts of hearing loss disproportionately impair speech-in-noise perception — ch. 26
510. Tinnitus character signals underlying medical conditions — ch. 26
511. Reduced dynamic range makes linear hearing aid amplification unsafe — ch. 26
512. A missing audiometric shadow curve reveals feigned (non-organic) hearing loss. — ch. 26
513. Speech reception thresholds closely duplicate averaged audiometric thresholds — ch. 26
514. Central auditory processing diagnosis requires exclusionary peripheral and cognitive tests — ch. 26
515. The audiogram fails as a robust indicator of perceptual deafness deficits — ch. 26
516. Hearing aids often worsen rather than improve sound localization. — ch. 26

Annotation Roundup

Question

• The audiogram measures only detection and conceals varied sensorineural perceptual deficits. — Worth chasing: what supplemental perceptual measurements exist and how do they change hearing aid algorithm recommendations in practice?
• Early psychoacoustics neglected loudness because sound intensity could not yet be controlled. — Interesting that frequency and spatial cues were manipulable with simple physics (strings, tuning forks, head shadowing) but intensity was not — worth understanding why decoupled intensity control took until the 1920s.
• Wundt built drop-based devices isolating intensity from frequency for controlled study. — How exactly did a dropped pendulum/pnometer achieve constant-frequency variable-intensity control, when other methods could not? The mechanics matter for understanding the experimental constraint.
• Bell Labs research priorities were shaped by telephone engineering needs — Worth noting: the absence of pitch and spatial hearing research at Bell Labs means early psychoacoustic frameworks were implicitly intensity-focused — a possible blind spot carried into later theory.
• Sensorineural hearing loss compresses the full loudness range into fewer decibels — What mechanism explains how dynamic range shrinks while total loudness range stays similar? This seems like a paradox worth understanding at the cochlear level.
• The audiogram measures only detection thresholds, so it misses everyday speech-in-noise ability. — What specific deficits beyond the threshold would better assessment tools capture — loudness recruitment, temporal resolution, spectral processing?
• Early psychoacoustics lacked tools to control sound intensity independently of frequency — Worth chasing: exactly which technologies of the 1920s (vacuum-tube oscillators? condenser microphones?) finally decoupled intensity from frequency control?
• Bell Labs pursued only hearing questions relevant to telephone engineering. — Implies pitch and spatial hearing research lagged because of commercial priorities - when and why did these fields later develop?
• The audiogram only captures detection thresholds and fails to predict real-world speech perception — What candidate replacement metrics exist — speech-in-noise tests, psychoacoustic tuning curves, temporal processing measures — and which shows clinical promise?
• Middle ear stiffness reduces low-frequency gain while added mass reduces high-frequency gain — Worth chasing: what specific audiogram shapes do otosclerosis vs. otitis media produce at early vs. late stages, and how do clinicians distinguish them?
• Time and frequency representations are linked so short durations broaden bandwidth — Worth chasing later: this uncertainty tradeoff underpins how hearing-impaired listeners’ reduced frequency resolution interacts with temporal cues — an application angle.
• Live cochleas are much more sharply tuned than cadaver measurements suggested — What mechanism (outer hair cell motility?) explains why tuning sharpens at low levels? The text teases this and 228 answers it.
• Noise can damage high-threshold auditory fibers while audiograms still look normal — Worth chasing: what are practical supra-threshold tests clinicians could actually use?
• Free-field hearing thresholds can exceed headphone thresholds by over 15 dB — Which anatomical structures amplify what frequencies to create free-field advantages? Worth tracing in a later chapter on sound conduction.
• The audiogram’s inverted axis breaks standard scientific plotting convention — Why did audiology adopt the upside-down audiogram historically? Worth chasing up the Ch. 1 rationale and Jerger 1990.
• Hearing loss does not change the psychometric function’s 12-dB detection range — Why does hearing loss not flatten or steepen the psychometric function? Worth checking the original Marshall & Jesteadt findings.
• Response bias distorts threshold measurements in hearing experiments. — Methods like two-interval forced choice and yes-no procedures differ in whether criterion shift can bias threshold estimates — worth mapping.
• Threshold from up-down staircases is the averaged level at response reversals. — Why does ‘2-down 1-up’ vs ‘3-down 1-up’ change the accuracy of the estimated threshold — what points on the psychometric function does each procedure converge to?
• Response bias distorts threshold measurements in hearing experiments. — How strongly do motivation differences between research volunteers and clinical patients bias real threshold estimates?
• Energetic and informational masking operate through distinct peripheral and central mechanisms — The boundary between peripheral energetic and central informational masking is worth probing later — where exactly does the mechanism split?
• The excitation pattern is the internal representation of a stimulus spectrum — How exactly is the excitation pattern measured or derived from masking data? Worth chasing in the body of the chapter.
• Broadband maskers at low levels mask mid frequencies more than extremes. — Worth chasing: why does broadband noise mask high frequencies slightly more than low once masking begins — is this tied to unequal basilar-membrane bandwidth or critical-band spread?
• A masker masks most when its frequency matches the signal frequency — The Wegel and Lane 1924 study could be worth tracking down as the origin of masking research.
• The ear’s frequency selectivity is imperfect and worsens at higher frequencies — Why is the critical band roughly constant below 500 Hz? Is this tied to basilar membrane mechanics or place coding?
• Identifying a vowel requires at least two of its formants — The chapter poses how much across-frequency integration the ear performs — a puzzle refined but not fully resolved.
• Simultaneous masking yields broader tuning curves than forward masking. — Why is the simultaneous-masked PTC broader? The text gestures at nonlinear processing but doesn’t fully spell out the mechanism here — worth chasing in Moore, Glasberg, and Roberts.
• Intensity discrimination improves with level for tones, violating Weber’s law — Why does the near miss hold for tones but not for noise above 20 dB SL? The chapter gestures at multi-frequency integration — worth chasing the mechanism further.
• Near-threshold sounds may sound louder to impaired than to normal ears — Why would near-threshold sounds seem louder in damaged cochleas? What mechanism — reduced compression, spontaneous activity changes — explains it?
• Loudness cannot be explained by single auditory nerve fiber firing alone — What central mechanisms transform BM vibration into loudness? This sets up the coding-of-intensity question to be answered next.
• Reaction time measures loudness in animals and language-disabled people — Could reaction-time loudness testing be applied to hearing-impaired infants who cannot report loudness judgments — a clinical screening avenue worth chasing?
• The near miss to Weber’s law results from the ear using spread-of-excitation across frequency — Could explore how sloping hearing-loss listeners effectively ‘block’ the near miss naturally and whether this predicts their Weber fractions before formal loss onset.
• Elevated gap detection thresholds in hearing loss stem from threshold elevation, not temporal pathology — This confound — elevated thresholds disguising temporal deficits — seems directly parallel to the audiology reading purpose; worth chasing what corrected measures exist.
• Stimulus fluctuations hurt gap detection but aid speech perception elsewhere — How exactly does the ear ‘listen in’ the low-amplitude temporal epochs, and why does this benefit speech but worsen gap detection?
• Comparing hearing-impaired and normal listeners requires controlling for both sensation level and absolute level — Does the noise-masking simulation distort perception in ways beyond threshold elevation, biasing the control condition? Worth chasing.
• Presenting speech at the same loudness minimizes forward-masking differences — Raises the clinical question of whether normalizing loudness perception (e.g. via compression amplification) could reduce forward-masking deficits, worth chasing in the hearing-aid chapters.
• Gap detection and amplitude modulation are usually intact after sensorineural loss — Why would temporal integration suffer but gap detection and AM be spared? This dissociation is exactly the kind of pointer to distinct neural mechanisms worth deep-diving.
• Hearing-impaired ears can outperform normal ears at amplitude modulation detection — A surprising counterexample to the simple ‘hearing loss degrades temporal processing’ story — worth understanding what circumstances produce superior AM detection.
• Hearing loss reduces audibility and restricts usable bandwidth for temporal processing — Did the noise-masker simulated-loss listeners show the same shallower slopes, or only the real-hearing-loss group? The passage implies but does not state the simulated result.
• Sensory neural hearing loss preserves temporal resolution when audibility is compensated — What mechanism makes temporal resolution spared in SNHL while masking and integration degrade? This seems worth chasing in the audiology literature.
• Helmholtz’s place theory failed to explain all pitch phenomena, prompting more complex models. — What specifically did modern experiments show that broke Helmholtz’s model? The chapter promises the failings ahead.
• Pitch perception involves both spectral and temporal representations of sound — Which empirical findings would decisively distinguish the pure place, pure temporal, and spectral-temporal codes from one another?
• Pitch can be derived from harmonic spacing even without the fundamental present. — This sets up the classic question of whether the missing fundamental is still perceived — worth verifying how the audiogram relates.
• Pitch has no magnitude like loudness, so magnitude scaling misapplies to it. — What physiological mechanisms actually differ between low and high frequency pitch perception implied here?
• Hearing impairment disrupts both place and temporal pitch codes — Worth chasing: the Hopkins & Moore (2011) study showing temporal-code disruption in hearing loss — what exactly did it measure?
• Audiograms and frequency selectivity fail to predict pitch perception deficits — If audiogram and tuning curves don’t predict FDLs, what does? This hints at a fundamental gap in current theories of cochlear impairment.
• Hearing-impaired listeners usually hear the correct pitch but with more variability — Worth chasing: what mechanism produces greater pitch shifts with intensity in impaired listeners specifically?
• Hearing-impaired frequency discrimination does not correlate with audiogram or frequency selectivity — Why would FDLs not correlate with frequency selectivity if poor selectivity should degrade place-based pitch? Points to unresolved role of temporal code.
• Increasing intensity improves frequency discrimination, much more at low frequencies — Why would intensity matter far more at 800 Hz than 8000 Hz? Possibly because low-frequency place cues depend on excitation spread that intensity sharpens.
• Pitch perception involves both spectral and temporal representations of sound — What exactly distinguishes ‘weak’ temporal pitch from the strong pitch of the place code? The next passages deepen this.
• Removing harmonics degrades f0 discrimination but it stays precise without them — A striking quantitative anchor: F0DL of ~2.5% even with harmonics removed - worth noting for pitch perception application detail.
• Small detection-threshold gains amplify into much larger identification-level changes — Worth confirming the mechanism by which the four perception levels amplify a 1 dB threshold change into 15-20 percentage points.
• Pinnae shape the sound spectrum to encode elevation and front-back position — How does the binaural auditory system segregate monaural spectral pinna cues from genuine interaural differences? The cue-conflict question is worth pursuing.
• Complex sounds allow envelope time-difference coding at high frequencies — How does envelope ITD coding interact with hearing-impaired listeners’ reduced temporal fine structure? This bears directly on the book’s stated normal-versus-impaired theme.
• Horizontal-plane localization needs no listener-specific HRTF, but vertical does — Why are pinnae cues so central to vertical-plane but not horizontal-plane localization? This suggests a deeper question about which localization cues the nervous system weights by plane.
• Even small hearing asymmetries across ears disrupt binaural hearing. — What magnitude of asymmetry disrupts binaural abilities, and through what mechanism — audibility or neural timing?
• Binaural summation largely survives sensorineural hearing loss when sounds stay audible — The Whilby finding of two distinct summation groups (less or more than normal) is striking but unexplained here — worth chasing the original study.
• Degraded interaural timing coding, not audiometric asymmetry, explains reduced MLD in hearing loss. — Why would interaural timing coding be the dominant driver of MLD reduction when level differences between ears contribute? Worth chasing how ITD coding degrades in SNHL mechanistically.
• Restoring audibility does not restore sound localization in hearing loss — What specific neural coding changes underlie the localization deficits untouchable by audibility restoration? This suggests central auditory processing damage distinct from peripheral sensitivity loss.
• Cochlear damage disrupts temporal fine structure needed by the MSO — Small traveling-wave delays after cochlear ‘death’ — what exact cochlear condition is meant, and how large are the measured delays?
• Hearing loss correlates weakly with precedence-effect echo thresholds. — Worth chasing: why would hearing-impaired listeners differ so widely in echo thresholds even at matched sensation levels, and what predicts who is affected?
• Signal Detection Theory principles help audiologists extract true thresholds from feigning patients — How are pseudohypacusis patients distinguished from those with genuine conservative response styles? Is feigning consciously intentional in most cases?
• Auditory processing disorder is a contested diagnosis lacking a single-locus definition — Worth chasing the Moore et al. 2010 critique — what evidence undermines a single-locus APD?
• Hearing aid algorithms distort auditory cues yet still improve speech understanding — What exactly do modern hearing-aid algorithms distort, and which supra-threshold cues are most damaged? The excerpt gestures at this without naming the specific distortions.
• Whether loudness recruitment degrades speech perception remains unsettled — Whether recruitment actually degrades speech perception is contested across simulations and compensation experiments — worth chasing the conflicting studies.
• Hearing aids often worsen rather than improve sound localization. — Which specific hearing-aid features (microphone placement, compression of ITD cues) most actively corrupt ITD versus ILD cues?
• The choice of hearing aid prescriptive rule barely affects speech intelligibility. — Which prescriptive rules were compared, and does rule choice matter more for other outcomes like comfort or loudness perception?
• More hearing aid compression channels measurably degrade vowel perception in hearing-impaired listeners. — Worth chasing: why does performance plateau between 1-8 channels but collapse at 16? What threshold in channel count triggers the worst spectral flattening?
• Tinnitus loudness matches do not predict tinnitus annoyance or diagnostic value — What neural or attentional mechanism would explain loudness-annoyance dissociation? Does heightened salience or threat-response rather than intensity drive tinnitus distress?
• Speech reception thresholds closely duplicate averaged audiometric thresholds — If SRT is essentially redundant with the average audiogram, why is it still measured — what discrepancy signals retrocochlear involvement? Worth investigating. Xref
• Hearing-impaired perception studies illuminate the mechanisms behind normal hearing — Connects to the reader’s stated interest in normal vs. impaired hearing perception — this is the book’s core framing thesis.
• Standard audiological tests miss most of the perceptual abilities humans need to communicate — Connects to the reader’s standing interest in how clinical assessment under-measures real-world perceptual domains.
• The audiogram is a behavioral test rooted in a century of psychoacoustics — Connects to the reader’s clinical/psychoacoustic background and the stated goal of understanding normal vs. impaired hearing perception.
• Successful communication requires multiple distinct auditory perception abilities beyond simple detection. — Sets up the chapter’s recurring contrast of audiogram-only testing versus fuller perceptual batteries — relevant to any audiology or sensory-assessment reading.
• Weber’s law states JND is a constant fraction of stimulus magnitude — Connects to the reader’s auditory perception understanding — Weber’s law is foundational for later frequency/level discrimination results.
• Pitch perception involves both spectral and temporal representations of sound — Previews Chapter 6 on pitch models; the spectral-versus-temporal duality should anchor that later material.
• Early hearing-loss assessment relied on tuning-fork duration and distance thresholds. — Connects to the history of audiometry and how clinical hearing testing evolved into modern audiograms.
• Bell Labs research priorities were shaped by telephone engineering needs — A concrete instance of the ‘use-inspired basic research’ pattern — commercial engineering constraints shaping which scientific questions get asked.
• The telephone industry drove development of technologies for measuring hearing. — Connects to engineering-driven science and to later chapters on intensity measurement.
• Speech intelligibility indexes average signal-to-noise ratio across critical bands — The Speech Intelligibility Index is a predictive model directly usable in audiology practice, connects to any later chapter on speech perception and hearing-aid fitting.
• Harvey Fletcher pioneered threshold measurement, loudness relations, and the masking model. — The masking model and loudness-frequency relations connect forward to Lentz’s own Chapter 4 on loudness; useful anchor for chapter-by-chapter concepts.
• Early audiogram standardization debates concerned level units and axes, not frequency scaling. — Wegel plotting frequency in octaves anticipates the modern audiogram’s log-frequency axis; connects to why audiograms today look the way they do.
• Sensorineural hearing loss compresses the full loudness range into fewer decibels — Connects to the reader’s whole stated purpose — this is the founding concept distinguishing normal from impaired hearing perception.
• The dynamic range of hearing is largest between 500 and 6000 Hz — Dynamic range of hearing connects to loudness growth and recruitment concepts if later chapters address hearing-impaired loudness perception.
• Hearing loss was first quantified as a percentage of remaining dynamic range — This percentage-of-dynamic-range approach anticipates modern speech-in-noise measures of hearing handicap, where remaining usable range matters more than absolute threshold.
• Threshold measurement method, not listener differences, caused the 10 dB gap — The discovery that psychophysical method (ascending/descending method of limits) changes measured thresholds is a classic in signal detection theory and psychophysics — connects to Fechner’s and Stevens’ work on measurement methodology.
• The audiogram measures only detection thresholds, so it misses everyday speech-in-noise ability. — Connects to the reader’s interest in models of hearing — a critique of threshold-only assessment that motivates suprathreshold perceptual models discussed later in the book.
• Early 20th-century hearing research was steered by telephone engineering needs. — Parallels the earlier Books/The-Library reading on how institutional goals shape scholarly practice, and the general theme that technology frames which questions a field asks.
• Fechner made conscious perception measurable and founded experimental psychology — Fechner’s interchangeability thesis underlies the Stevens Power Law and measurement debates familiar from psychophysics literature.
• Binaural sound localization depends on ear-level temporal and intensity encoding efficiency — Connects to the reader’s broader interest in models of hearing; the two-cue duplex mechanism parallels the spectral/phase cue distinction familiar in visual psychophysics.
• Early psychoacoustics lacked tools to control sound intensity independently of frequency — Illustrates the ‘availability of instruments shapes which questions get asked’ dynamic, parallel to the Milgrom/Weber material on how institutional or practical constraints channel inquiry.
• Earliest hearing-loss tests measured duration and distance of audibility — Directly relevant to the reader’s core interest in how hearing impairment was historically assessed before audiometry existed.
• Corporate and technical goals, notably telephony, shaped which auditory abilities researchers studied — Parallels how contemporary research funding agendas (e.g., hearing aid and cochlear implant industries) steer what hearing science investigates.
• Lower-level auditory deficits cascade upward but not all higher-level deficits trace downward. — This one-directional hierarchical dependency in hearing mirrors cascading failure structures in other sensory and cognitive systems - a useful framework.
• Audiograms test pure-tone detection because pure tones are maximally frequency-specific — Ties to the classic audiogram figure with the ‘speech banana’ band of conversational speech, familiar from hearing-loss literature.
• ASHA prescribes 1-2 second steady and 200-ms pulsed tones for audiometry — Relates to audiometric threshold-measurement protocol differences versus psychoacoustic testing.
• Outer and middle ear structures provide frequency-specific amplification of incoming sound — Connects to audiology basics on how conductive hearing loss arises from damage to these amplification stages.
• Combined outer and middle ear amplification spans roughly 600 to 4000 Hz — This amplification range corresponds to the most critical frequencies for speech perception, a useful bridge to hearing-aid fitting practice.
• Audiometry pure-tone durations are set by perception, not acoustic independence — Links acoustic ‘spectral splatter’ theory to the audiology practice standard (ASHA guidelines) the reader is building understanding around.
• Individual auditory nerve fibers cannot code the full hearing dynamic range — Directly connects to loss-of-compression and loudness-perception deficits in sensorineural hearing loss the reader tracks across chapters.
• Auditory nerve fibers divide into three types by spontaneous firing rate. — Connects to the three-fiber population model relevant to cochlear implant coding and hearing-loss characterization.
• Hearing depends on sequential physiological stages, each with distinct perceptual consequences when damaged. — Sets up the framework that later chapters use to explain site-of-lesion-specific psychophysical deficits.
• The mid-frequency hearing advantage explains why alarms and speech amplification target 1000-6000 Hz. — Central to the reader’s audiology applications goal: why amplification for sensorineural loss targets mid frequencies.
• Outer hair cell loss reduces hearing sensitivity by up to 60 dB — Ties directly to the reader’s interest in normal vs impaired hearing perception and to audiology applications.
• Live cochleas are much more sharply tuned than cadaver measurements suggested — Connects to the widely-taught von Békésy passive traveling-wave picture; the corrective here adds an important caveat to any textbook treatment of cochlear mechanics.
• High spontaneous-rate fibers have low thresholds while low SR fibers have high thresholds. — Plausibly connects to rate-level functions and firing dynamics the reader compiled in earlier chapters.
• Noise can damage high-threshold auditory fibers while audiograms still look normal — Ties to ‘hidden hearing loss’ literature — a normal audiogram with real supra-threshold deficits.
• The shape of the audiogram reflects outer and middle ear transfer, not cochlear transmission — Connects to the general understanding that best-hearing frequency range 600–6000 Hz matches speech-relevant frequencies.
• Response bias can contaminate any psychophysical threshold estimate — Echoes signal detection theory’s warning that perceptual measurements always mix sensitivity with decision criteria.
• Hearing-loss severity categories lead patients to underestimate their communication difficulties — Parallels findings elsewhere that categorical labels (IQ bands, risk categories) mislead laypeople about real-world severity.
• Hearing loss does not change the psychometric function’s 12-dB detection range — Builds on this book’s psychometric function coverage and the Marshall & Jesteadt citation from earlier passages.
• Threshold estimates reflect both ear sensitivity and listener response bias — Connects to signal detection theory and to any experimental-design concern about how yes/no answers vary with motivation.
• Response bias distorts threshold measurements in hearing experiments. — Connects to why clinical hearing tests use forced-choice procedures to minimize bias errors.
• Masking experiments revealed the auditory filter underlying frequency selectivity — Auditory filter concept connects to later work on cochlear tuning and the reader’s interest in normal vs impaired hearing mechanisms.
• Hearing loss acts like a filter attenuating specific frequencies — The filter-bank framing of auditory perception connects to auditory filter models of masking and to cochlear mechanical tuning studied in cochlea chapters.
• A masker masks most when its frequency matches the signal frequency — Connects to ‘The Soundscape’ reading on how sounds mask other sounds in the acoustic environment.
• Conductive hearing loss can be modeled as a filter, but sensorineural loss cannot — Connects to sensorineural distortions discussed throughout the rest of the book; reader building a normal-vs-impaired model needs this framework.
• Basilar membrane tuning is sharper in living than dead cochleae — Explains why earlier (von Békésy) estimates of poor tuning were wrong — ties to historical methodology across hearing literature.
• Masking patterns reveal the ear’s internal psychological representation of a sound. — Relates to the reader’s goal of understanding normal vs impaired hearing because masking patterns are measured differently (wider) in impaired ears — an internal-representation tool.
• Low-frequency maskers mask high-frequency signals more than the reverse, and this worsens with intensity. — Connects to the classic ‘upward spread of masking’ phenomenon well documented in audiology; pairs with cochlear mechanics where low-frequency basilar membrane traveling waves travel farther apically.
• A narrow noise band can mask signals multiple octaves away at high stimulus levels. — This nonlinear spreading of masking is central to understanding why loud low-frequency sounds drown out speech — relevant to hearing-aid fitting and cocktail-party listening.
• The notched-noise method directly measures auditory filter shape. — Connects to the reader’s ongoing interest in auditory filtering models and how they differ between normal and impaired hearing.
• Only low-numbered harmonics are resolved, higher ones blur together in the internal representation — Resolved vs. unresolved harmonics underpin pitch perception research, relevant to the reader’s interest in hearing models.
• There is a critical bandwidth beyond which adding noise power no longer increases masking — The critical band concept connects to cochlear frequency analysis and auditory filter models treated later in this book and in auditory neuroscience.
• The basilar membrane’s logarithmic spacing justifies plotting auditory representations on log frequency axes — The log-spacing of the basilar membrane connects to place theory of pitch and classic cochlear tonotopy.
• Simultaneous-masked PTCs are broader than forward-masked PTCs, with similar overall shape — Connects to earlier physiological tuning curves from the basilar membrane (Figure 3-4), per the passage’s own comparison.
• Two-tone suppression makes simultaneous masking appear broader than forward masking — Explains why simultaneous and forward-masked tuning curves disagree — relevant to modeling hearing-impaired vs. normal frequency selectivity.
• Fluctuating maskers produce masking release that Fletcher’s power spectrum model cannot explain. — The masking-release results connect to later ch. 7 material on cochlear amplitude compression and how compression enables dip listening — a core mechanism that will come back when discussing hearing loss.
• Cochlear damage increases susceptibility to masking, hurting speech in noise. — This causal claim is the central problem that amplifies the reader’s whole purpose across the book, contrasting normal dip-listening with impaired cochleae.
• Hearing loss impairs frequency selectivity beyond what stimulus level differences explain. — Ties to the earlier claim (locations 130s) that frequency selectivity worsens with increasing stimulus level in normal hearing; here that real effect is isolated from the pathology’s own contribution.
• Loss of cochlear suppression explains similar PTCs across masking conditions. — The suppression mechanism here parallels the two-tone suppression discussed in earlier chapters on cochlear mechanics/otoacoustic emissions.
• Reduced frequency selectivity hurts speech perception less than reduced audibility does — Connects to audiology’s classic audibility-vs-distortion debate over how much of hearing-impaired speech difficulty is remedied by amplification alone.
• Listeners use distributed spectral information but not all of it — The finding that listeners underperform best-performance models parallels informational-masking and channel-capacity results from other auditory literature.
• Masking by bandlimited noise depends only on masker energy within the critical band. — This is the psychoacoustic expression of spectral integration: once noise fills the ear’s filter at the probe frequency, extra bandwidth adds nothing - parallel to how energy summation works within a single auditory filter.
• Sensorineural hearing loss worsens masking beyond mere threshold elevation — Connects to the reader’s interest in normal-vs-impaired hearing perception differences central to this book’s goal.
• Reaction time measures loudness across the full hearing range — Relates to animal psychoacoustics testing and to behavioral measures in hearing research, a key methodological contrast to magnitude estimation.
• A tone and wideband noise of very different levels can equally sound loud — Ties to spectral loudness summation and the channel-based loudness model concepts elsewhere in psychoacoustics reading; also connects to how hearing aids must compress versus amplify different bandwidths.
• Reaction time spans the full hearing range where psychometric functions cover only 10-15 dB — Plugs into the earlier chapters’ coverage of psychometric functions and absolute threshold detection methods.
• Reaction time measures loudness across the full hearing range — Directly serves the reading purpose of normal vs impaired hearing — reaction time opens loudness measurement to animals, language-disabled humans, and hyperacusis patients.
• Larger baseline weights require proportionally larger differences to be noticed — The weightlifting analogy for the JND connects to Stevens’ and Fechner’s work and to the psychophysics of lifted weights the reader knows from other psychophysics sources.
• Absence of recruitment in sensorineural loss signals retrocochlear pathology. — Connects to clinical diagnostic use of psychoacoustic measures, relevant to audiology application focus.
• A 10 dB increase always doubles perceived loudness above 40 dB — Connects to the decibel/log-scale material in earlier chapters of this text on intensity scaling.
• The phon scale defines loudness relative to equal-loudness matches at 1 kHz — The phon-as-equal-loudness-reference concept parallels loudness scaling issues in other psychoacoustic sources read; an anchoring-standard idea.
• Categorical loudness scaling measures uncomfortable and comfortable loudness levels using verbal categories — Connects to clinical audiology testing conventions (UCL/MCL) used in hearing aid fitting.
• Outer and middle ear damage changes the loudness frequency balance — dB A weighting connects directly to the noise-exposure and industrial dosimetry topic from the One Square Inch silence reading.
• Fletcher and Munson’s 1933 loudness data remain essentially accurate today. — The longevity of Fletcher-Munson curves echoes classic results in other perceptual sciences that survived later measurement improvements.
• Basilar membrane vibration can be measured in vivo by tracking a bead’s movement — Plausibly connects to earlier psychoacoustics chapters/CD content on cochlear mechanics and outer hair cell amplification.
• Wide bandwidth noise sounds as loud as a narrower tone despite lower level — Connects to earlier chapters’ coverage of auditory filters and excitation patterns, and prefigures what hearing loss does to loudness summation.
• Hearing-impaired listeners show faster loudness growth but similar discomfort thresholds — Recruitment — rapid loudness growth in hearing loss — connects to the loudness models and compression concepts developed in audiology chapters.
• Outer hair cell damage steepens the basilar membrane’s growth function — Connects to cochlear amplifier / OHC motility models in hearing science; the compressive nonlinearity is the assumed basis of the ‘loudness recruitment’ phenomenon in impaired hearing.
• Magnitude estimation lets listeners assign numbers proportional to perceived loudness. — Links to the reader’s prior interest in the psychophysics of loudness and Fechner/Stevens power-law scaling traditions.
• Graph scaling choices shape the inferred form of loudness functions. — A warning about interpreting log-plotted data that echoes classic science-communication pitfalls - related to crafting a knowledge base entry on reading log plots.
• The auditory system’s ~120 dB dynamic range exceeds any single nerve fiber’s coding capacity — Connects to why hearing loss compresses dynamic range and why hearing aids need wide-dynamic-range compression.
• A-weighted decibels better predict hearing damage than unweighted sound pressure level. — Reinforces why noise dosimetry standards in occupational health use dB A; connects to noise-damage reading.
• Gap detection thresholds improve with increasing stimulus bandwidth but not frequency region — Connects to the time-frequency trade-off discussion from earlier chapters on signal processing and spectral splatter.
• Inserting a temporal gap into a stimulus produces spectral splatter at the gap edges — The time-frequency trade-off recalls the Heisenberg uncertainty principle logic from physics and could connect to how resolution limits structure any measurement system.
• Gap detection thresholds improve with increasing stimulus bandwidth but not frequency region — Connects to the Milgrom/Shapiro reading on institutions: a diagnostic signal can be confounded by how the listener is positioned, like reputation signals confounded by monitoring access.
• Gap detection thresholds improve with increasing stimulus bandwidth but not frequency region — Connects to auditory filter bank and spectral representation discussion in Chapter 3 of this same book.
• Narrow-band devices like telephones degrade temporal cue coding and raise listening effort — Connects to listening-effort literature and to why hearing aids with limited bandwidth may impair temporal resolution even when speech intelligibility looks intact.
• Stimulus fluctuations hurt gap detection but aid speech perception elsewhere — Fluctuating masker benefit and listening-in-the-dips connects to the listener’s stated interest in normal vs. impaired hearing differences in noise.
• Temporal modulation detection is independent of hearing threshold — Directly serves the reader’s goal of understanding hearing-impaired perception — this is the interpretive bridge from measured thresholds to neural representation.
• Forward masking reveals how the ear’s perceptual representation of sound decays over time — Similar to Plomp’s gap detection paradigm explicitly noted; both are temporal-resolution measures suitable for comparing normal vs impaired hearing.
• Wide bandwidth improves temporal perception while low-pass filtering limits it — Connects bandwidth/temporal tradeoffs to hearing-aid frequency-response design for impaired listeners.
• Gap detection offers quick but shallow measures of temporal acuity — Feeds the reader’s goal of a comparative toolkit of temporal-resolution measures; useful contrast against TMTF and forward masking as alternative methods.
• Soft sounds give the ear inadequate access to rapid amplitude changes in speech — Directly relevant to the reader’s impairment questions: explains listening effort for those with elevated thresholds.
• The energy detector model fails because it accumulates interfering noise along with signal energy. — The energy-vs-information critique parallels the signal-detection and information-processing critiques that motivated cognitive psychology’s shift from energy-based to information-based models.
• Temporal integration models divide on time constant assumptions of hundreds versus single-digit milliseconds. — Connects to the reader’s interest in hearing-perception models and theories; the long vs short time constant split parallels similar debates about integration windows in vision and attention research.
• Sensorineural hearing loss disrupts some temporal abilities but not others, with wide individual variability — Ties to the reader’s interest in distinctions across hearing-impaired perception; also caution against group generalizations.
• Hearing loss reduces audibility and restricts usable bandwidth for temporal processing — Connects to earlier chapters on gap detection and forward masking findings (Plomp, Viemeister, etc.) referenced as background.
• Forward masking decay slows markedly after masker offset in hearing loss — Links to chapter 5 temporal processing and to signal-detection masking theory laid out in chapters 3-4.
• Gap detection and amplitude modulation are usually intact after sensorineural loss — Dissociated deficits across psychoacoustic tasks echo the reader’s broader theme of what hearing loss preserves versus destroys — relevant to both-normal-vs-impaired comparisons collected across the book.
• Hearing-impaired listeners gain half or less benefit from longer stimulus durations — Connects to the reader’s running interest in how SNHL alters specific psychoacoustic mechanisms — here temporal integration — as one of the systematic deficits.
• Similar critical durations do not imply normal temporal integration — Echoes the common-appearance-vs-underlying-function trope throughout this book where superficially normal metrics still mask distinct deficits.
• Sensorineural hearing loss reduces temporal integration benefit by half or more — Connects to the reader’s broader interest in how impaired hearing differs mechanistically from normal hearing across chapters 1-13 of this same book.
• Hearing loss extends internal masker persistence and shrinks duration benefits — Connects to the forward-masking and temporal-integration mechanisms described throughout this chapter’s framework of relative threshold.
• Pitch lacks a magnitude dimension, complicating its subjective measurement — Directly parallels the loudness assessment techniques from earlier chapters and the reader’s broader psychoacoustics project on perception measurement.
• Harmonic amplitudes shape timbre and loudness but not pitch. — Directly the source-filter theory of speech production (Fant, source at glottis; filter at vocal tract) central to phonetics.
• Physiological coding of frequency does not by itself explain perceived pitch. — Mirrors the ‘physiology vs perception’ gap discussed in auditory masking and loudness chapters; also the general lab-to-real-world problem in hearing science.
• Removing low harmonics from a complex tone leaves its pitch unchanged. — Connects to audiology textbooks’ ‘residue pitch’ and to how phone speakers compress speech so fundamental isn’t physically present.
• Pooled neural firing encodes stimulus period as spike intervals. — This is the volley theory mechanism in action — complements the Wever-Bray theory described two paragraphs earlier.
• Pitch arises from where along the cochlea a sound maximally stimulates — The Fourier-analyzer ear concept echoes how signal processing and cochlear modeling work in related auditory science reading.
• Fundamental frequency is coded dually via harmonics and envelope rate — The dual coding of F0 (place via harmonics, temporal via envelope) connects to the classic ‘residue’ or ‘missing fundamental’ literature and to cochlear-implant coding design.
• Across-filter neural synchrony provides a robust pitch code — Connects to autocorrelation models like Licklider’s duplex theory of pitch perception read elsewhere.
• Pitch cannot be measured absolutely, only relative to another tone — Parallels the loudness measurement problem described earlier in the book — same why-relative measurement logic applies across auditory qualities.
• Audiograms and frequency selectivity fail to predict pitch perception deficits — Connects to models where place codes predict tuning-curve-linked FDLs; the failed prediction reinforces temporal-code involvement.
• Hearing loss disrupts pitch via place, temporal, and interaural mechanisms. — Contradicts the textbook-standard assumption that SNHL pitch problems reflect broadened auditory filters; ties hearing-impaired to temporal coding literature from earlier chapters.
• Hearing loss disrupts pitch via place, temporal, and interaural mechanisms. — Diplacusis (interaural pitch mismatch) and contradictory pitch codes are concrete clinical phenomena connecting to audiology applications.
• Reported pitch-with-intensity shifts vary widely with method — Connects to the loudness chapters on intensity perception and to measurement methodology debates recurring through the book and in psychophysics generally.
• Place code governs pitch perception of pure tones above about 4 to 5 kHz — Connects to the traveling wave peak shift and intensity effects covered earlier in the hearing-mechanisms material.
• FDL findings compromise a purely temporal account of low-frequency pitch. — The phase-locking constancy across intensity relates to earlier temporal coding chapter detail about firing synchrony.
• The residue pitch refuted Helmholtz’s place theory of pitch percept. — This historical falsification of the place model via masking connects to how modern dual place/temporal theories are framed in later chapters and to similar theory-replacement arcs in hearing science.
• The existence region supports a place-based harmonic template model of pitch — Shows the place vs. temporal coding debate from earlier chapters being resolved in favor of place coding for this phenomenon — a model-comparison the reader will want to track across chapters.
• Sounds missing many harmonics still evoke a weak pitch sensation — Connects to the place vs. temporal code debate in pitch perception — relevant to models of hearing for the reader’s research.
• Pitch enables voice identification and the cocktail party listening effect — “Auditory scene analysis” / cocktail party phenomenon - links closely to the reader’s interest in how normal listeners separate talkers in noise.
• Individual hearing-impaired listeners compensate by relying on whichever pitch code remains intact — Pattern of variable individual compensation parallels adaptive-reweighting findings from normal cochlear-implant and audiometric research.
• Raising intensity lowers pitch at low frequencies but raises it at high frequencies. — This frequency-dependent pitch-intensity interaction echoes the complex direction reversals familiar in auditory psychophysics — comparable to level-dependent loudness growth differences between frequency regions.
• At 1000 Hz humans detect frequency changes of about 0.2 percent — Connects to Weber-fraction psychophysics in other perception domains (vision contrast, weight discrimination).
• Increasing intensity improves frequency discrimination, much more at low frequencies — Pattern of larger level effects at low frequency echoes temporal-coding theories of pitch that operate mainly below a few kHz.
• Absolute frequency discrimination worsens as reference frequency increases — Contrasts with the intuition that all frequencies are equally resolvable; dovetails with cochlear place-coding models.
• The Weber fraction for frequency declines below 1500 Hz then rises above 2000 Hz — Non-constant Weber fraction across frequency points to a non-Weberian regime, useful when cross-comparing pitch models.
• Random intensity variation disrupts place but not temporal pitch coding — Relates to the reader’s broad interest in distinguishing mechanism accounts of perception via experimental dissociation.
• Both place and temporal codes could underlie pitch, confounding identification of the main code — This dual-code framing connects to the reader’s interest in hearing-impaired perception — which code is degraded by hearing loss.
• Melodic interval identification degrades once about 9-10 harmonics are removed — Reproduces in pitch perception what the reader’s broader exploration of normal vs. impaired hearing needs: a concrete behavioral boundary (9-10 harmonics) as a perceptual reference.
• Resolved harmonics use place pitch coding while unresolved harmonics use temporal coding — Connects to the reader’s interest in models of perception - this institutionalizes the dual-mechanism idea basic to hearing science.
• Small detection-threshold gains amplify into much larger identification-level changes — Connects to Erber’s four levels of perception, a hierarchy useful for audiology clinical practice in this book.
• Ear separation on one axis makes horizontal binaural cues strongest — Sets up why pinnae (monaural cues) are needed for front/back and elevation disambiguation — relevant to the pinnae section mentioned here.
• Two-ear listening improves sound-field thresholds by 10 to 15 dB — Connects to Chapter 2’s MAP vs MAF threshold discussion already in the reader’s notes.
• The just-detectable speaker shift defines the minimum audible angle. — Establishes the spatial analog of auditory acuity that later chapters will compare in hearing-impaired listeners.
• Headphone studies reveal ILD perception abilities hidden by natural field acoustics — Connects to the ILD/frequency dependence work of Feddersen et al. and the broader binaural hearing aid/cochlear implant angle.
• Horizontal-plane localization needs no listener-specific HRTF, but vertical does — Connects to spatial-audio engineering for VR/headphones, specifically whether generic HRTFs suffice.
• Antiphasic speech improves word identification by 20 percentage points at low SNRs. — Relates to earlier chapters on how masking and signal-to-noise ratio shape auditory perception; also to the reader’s broader goal of understanding hearing-impaired vs. normal speech perception failure.
• The first arriving sound wave dominates perceived localization regardless of level — Relates to how reverberation degrades speech and localization — connects to listening in rooms and hearing-aid processing that amplifies reflections.
• Complex sounds allow envelope time-difference coding at high frequencies — Reconciles the 1000-Hz phase limit with the fact that we localize real high-frequency sounds; a key bridge between binaural theory and everyday perception.
• Horizontal-plane localization needs no listener-specific HRTF, but vertical does — Connects to the earlier chapter content on ILDs and ITDs dominating horizontal cues while spectral cues serve vertical localization.
• The precedence effect reduces masking from reflections in rooms — Connects to echo suppression and the design of hearing aid/assistive-listening algorithms; relevant to the reader’s interest in applied audiology.
• Head shadow makes high-frequency binaural cues inaudible in sloping hearing loss — Interfaces with the reader’s broader goal of separating audibility confounds from genuine binaural processing deficits in hearing-impaired listeners.
• Low sensation level impairs ITD and ILD discrimination even in normal listeners — Crucial confound for the reader’s normal-vs-impaired comparison: low sensation levels alone (without pathology) degrade binaural cue discrimination — an audibility-level effect masquerading as impairment.
• Hearing aids cannot restore sound localization because coding damage, not audibility, is the cause — Connects to general audiology theme that amplification compensates audibility but not neural processing deficits, echoing themes from earlier MLD binaural processing chapters.
• Hearing-impaired listeners benefit roughly two-thirds less from binaural squelch than normal-hearing listeners. — Quantifies the binaural squelch deficit with concrete dB numbers — connects to the reader’s broader project on normal vs. impaired hearing perception differences.
• Echo-fusion thresholds vary widely among hearing-impaired listeners regardless of audiometric thresholds. — The repeated finding that audiometric threshold predicts little about temporal/binaural processing echoes the same dissociation seen throughout this text and connects to the reader’s overarching question about what audiograms fail to capture.
• Degraded interaural timing coding, not audiometric asymmetry, explains reduced MLD in hearing loss. — Ties the binaural mechanism material of this chapter to the reader’s broader question of how normal vs impaired hearing differ causally.
• Hearing loss correlates weakly with precedence-effect echo thresholds. — The recurring ‘no correlation with audiometric threshold’ pattern echoes the reader’s interest in why standard audiograms fail to capture real perceptual deficits.
• Low-level auditory deficits cascade upward to impair speech comprehension — Relates to trade-regime cascade arguments about how failures at one level propagate; also to hierarchical models of signal processing generally.
• Word recognition that declines with louder speech signals retrocochlear pathology. — Connects to the psychometric function and loudness growth discussions earlier in the book on how cochlear vs retrocochlear sites of lesion differ diagnostically.
• Signal Detection Theory principles help audiologists extract true thresholds from feigning patients — Applies Signal Detection Theory (already introduced in earlier chapters of this book) to a clinical diagnostic problem — criterion manipulation as an audiological lever.
• Hearing aid algorithms distort auditory cues yet still improve speech understanding — Connects to the reader’s interest in how imperfect assistive technologies still deliver net benefit — parallels the extralegal contracting and reputation-system discussions where flawed mechanisms outperform their absence.
• Frequency selectivity in normal-hearing listeners worsens at high sound levels — Connects to the hearing-aid fitting dilemma and upward spread of masking themes from earlier psychoacoustics chapters on masking.
• Hearing aids often worsen rather than improve sound localization. — Connects to the earlier chapter material on ITD/ILD and pinna cues for localization; a binaural deficit these devices silently fail to correct.
• More hearing aid compression channels measurably degrade vowel perception in hearing-impaired listeners. — Tension between this channel-count finding and the design goals of cochlear implants and multi-band compressors, where more channels are usually assumed better.
• WDRC processing distorts the temporal cues hearing-impaired listeners rely on for stop consonants — Connects to the reader’s interest in how impaired spectral representation forces reliance on temporal cues, complementing the temporal-cue chapters earlier in this book.
• Independent compression in each ear distorts binaural localization cues — Connects to the reader’s broader interest in normal vs impaired hearing perception and how assistive tech alters acoustic cues.
• Tinnitus has no objective diagnostic test and is diagnosed by self-report alone — Ties to psychoacoustic measurement methods discussed earlier in the book — matching loudness, pitch, and timbre to characterize a phantom percept.
• The audiogram fails as a robust indicator of perceptual deafness deficits — Connects with the broader theme that clinical standard measures miss real perceptual variation—parallels other domains where diagnostic surrogates diverge from lived experience.
• Deficits at lower perceptual levels propagate upward through Erber’s hearing hierarchy — Hierarchy-of-processing logic parallels the reader’s interest in how deficits propagate from detection to comprehension across perceptual systems.
• Small amounts of hearing loss disproportionately impair speech-in-noise perception — Connects with the book’s own auditory scene analysis material; also links to audiogram interpretation in clinical audiology.
• Tinnitus pitch spans the entire region of hearing loss, not a single frequency — Connects to the general theme of cochlear damage and reorganization producing phantom percepts; plausible ties to edge theory of tinnitus generation elsewhere in the field.
• Behavioral psychoacoustics tests detect retrocochlear pathology poorly but rule out healthy ears well — Connects to earlier chapters’ discussion of loudness recruitment, otoacoustic emissions, and ABR as physiological correlates of cochlear vs neural sites; also links to general screening-test logic where specificity and sensitivity trade off.
• Re-instructing suspected feigners shifts their decision criterion toward true thresholds — Signal Detection Theory reapplied clinically — directly connects to the book’s earlier chapters laying out SDT criterion and sensitivity concepts.
• Prolonged forward masking makes vowels mask consonants in impaired ears — Ties to the temporal-masking and gap-detection material from earlier chapters; glosses why vowels swamp consonants in impaired perception.
• Hearing loss is a sensory-representation deficit, not merely an acoustic one. — Directly relevant to points on loudness recruitment, frequency resolution, and temporal processing established earlier in this book.
• More hearing aid compression channels measurably degrade vowel perception in hearing-impaired listeners. — Gives the reader a quantitative anchor (1-8 unchanged, worst at 16) for how many WDRC channels are too many.
• A 1 dB SNR improvement boosts intelligibility by 7 to 19 percent — Carries forward signal-to-noise and masking concepts from earlier chapters on normal hearing.
• Directional hearing aid microphones can degrade sound localization by attenuating lateral sounds — Connects to the reader’s interest in how auditory processing differs between normal and aided impaired listeners, and how assistive technology reshapes available cues. Seed
• The audiogram measures only detection and conceals varied sensorineural perceptual deficits. — An essay angle: why a century-old clinical test still dominates despite demonstrably capturing only one dimension of the experience it purports to assess.
• Physiological tests measure sound representation, never the perception itself — Article angle: why the gold standard of hearing assessment remains subjective self-report despite a century of objective technology.
• Early 20th-century hearing research was steered by telephone engineering needs. — Could anchor an essay on how commodity technology (telephone, now consumer audio) biases the research questions a perceptual science pursues.
• Earliest hearing-loss tests measured duration and distance of audibility — An article angle: how the history of hearing-test technology — from tuning-fork distance judgments to pure-tone audiograms — bounded what clinicians could even conceive of as hearing loss.
• The audiogram only captures detection thresholds and fails to predict real-world speech perception — An essay or professional piece arguing that clinical audiology’s century-old gold standard measures thresholds rather than the abilities that actually matter to patients.
• Noise can damage high-threshold auditory fibers while audiograms still look normal — Strong article angle: standard hearing tests miss damage that still causes real-world speech-in-noise difficulty.
• An unusually low false positive rate signals a patient exaggerating hearing loss — Angle: the diagnostic tell of malingering in audiology — how missing false positives reveals dissembling, inverting the usual clinical worry about too many false alarms.
• A narrow noise band can mask signals multiple octaves away at high stimulus levels. — An essay on why ‘it was so loud I couldn’t hear anything’ is literally true — upward spread of masking means loud bass leaves no auditory room for high-frequency detail.
• Loudness models can guide hearing aid programming and alarm design — An article angle: how computational loudness models could be turned into everyday assistive decisions - emergency tones, hearing aid presets per environment.
• Reaction time measures loudness across the full hearing range — Possible essay angle: reaction time as a ‘behavioral biomarker’ connecting animal and human auditory research, bypassing the need for language.
• Narrow-band devices like telephones degrade temporal cue coding and raise listening effort — Article angle: ‘decoding effort’ as an invisible cost of bandwidth-limited devices — the listening gets done, but at extra cognitive price the user pays silently.
• Prolonged forward masking makes vowels mask consonants in impaired ears — Angle for an audiology explainer: why hearing-impaired listeners mishear soft consonants after loud vowels and what speech-rate changes actually do.
• Pitch has no magnitude like loudness, so magnitude scaling misapplies to it. — Article angle: why a standard, still-used engineering scale for pitch is built on a conceptually flawed assumption that pitch has magnitude.
• Audiograms and frequency selectivity fail to predict pitch perception deficits — An essay angle: why the standard audiogram fails as a predictor of a core perceptual deficit — the gap between clinical measures and actual hearing experience.
• Missing fundamental pitch survives even when cochlear distortion is masked out — Angle: the missing fundamental as an existence-proof that perception constructs pitch rather than merely reads acoustic place — relevant to designing aids for hearing-impaired listeners.
• Headphone studies reveal ILD perception abilities hidden by natural field acoustics — A ‘what headphones can teach us that the free field cannot’ essay angle on how controlled lab stimuli isolate perceptual mechanisms.
• Pinna cues drive the need for individualized HRTFs in vertical localization — Angle for a piece on whether VR/audio tech should offer individualized HRTF calibration or generic profiles.
• Hearing aids address three deficits but leave frequency, temporal, and pitch processing unaddressed. — Could seed an explainer on the gap between what hearing aids actually fix and the deficits patients still report — namely speech-in-noise difficulty despite amplification. Define
• Physiological tests measure sound representation, never the perception itself — Clarifies the key distinction between measuring neural representation of sound versus measuring the subjective percept.
• Weber’s law states JND is a constant fraction of stimulus magnitude — Weber’s law defined: JND in weight is about 1/30th of the weight, generalizing across modalities.
• Psychoacoustics measures detection, discrimination, magnitude, and recognition of sounds — Defines the four foundational questions of psychophysics: detection, discrimination, magnitude, and recognition.
• Pitch perception involves both spectral and temporal representations of sound — Contrasts spectral (place) vs temporal theories of pitch, a core conceptual duality.
• Psychoacoustics explains perception through physiological mechanisms — Defines what psychoacoustics aims at: not just perceptual limits but their physiological basis.
• Modern audiology rests on the premise that perception connects to physics — Articulates the core methodological premise of the whole discipline: manipulate sound, measure perception.
• The decibel unit enabled standardized hearing characterization — Names the three weightings dB SPL, dB A, and dB HL that recur throughout the rest of the book.
• Speech intelligibility indexes average signal-to-noise ratio across critical bands — Defines SII (formerly Articulation Index), a working predictive model the reader explicitly wants as a concept for assessing hearing loss impact.
• Sensorineural hearing loss compresses the full loudness range into fewer decibels — Defines loudness recruitment: the counterintuitive phenomenon where sensorineural hearing loss shrinks dynamic range between threshold and discomfort while loudness still reaches normal upper levels.
• Audibility thresholds can be expressed on physical or perceptual decibel scales — Defines dB SPL (physical reference) versus dB HL (perceptual reference), a core distinction for hearing measurement.
• The 1935 Beasley survey first established US normal-hearing thresholds — Defines the dB SPL vs dB HL distinction: physical reference vs perceptual reference, which underpins audiometer calibration.
• Fechner made conscious perception measurable and founded experimental psychology — Defines psychophysics, its founding premise that perception and stimulus magnitudes are interchangeable, and the 1860 origin text.
• Binaural sound localization depends on ear-level temporal and intensity encoding efficiency — Names the Duplex Theory of Sound Localization and its two cues: interaural intensity (head shadow) and interaural time differences.
• Corporate and technical goals, notably telephony, shaped which auditory abilities researchers studied — Explains how the historical emphasis on thresholds, loudness, and masking arose from Bell Labs’ telephony needs rather than pure science.
• Auditory perception is a four-level hierarchy from detection to comprehension. — Lays out the Erber hierarchy — exactly the kind of conceptual framework the reader asked for — distinguishing detection, discrimination, recognition, and comprehension.
• Absolute threshold is the minimum detectable sound level without external noise — Defines absolute threshold, the foundational measure framing this whole chapter and the reader’s stated interest in hearing perception.
• Pure tones are used for audiometry because they are frequency-specific — Defines both the pure tone and the audiogram while explaining why this particular stimulus was chosen for clinical testing.
• Audiograms test pure-tone detection because pure tones are maximally frequency-specific — Explains what an audiogram is and why pure tones anchor audiometry, core background for the reader’s audiology-oriented goal.
• Short tones smear extra frequencies into their spectra, a cost called spectral splatter. — Defines spectral splatter and bandwidth as consequences of shortening a tone.
• Shorter sounds necessarily have broader spectral bandwidths — Explains the time-frequency tradeoff, a core acoustics concept the reader asked for.
• Longer pure-tone durations produce narrower spectral peaks with less splatter — Ties the spectral splatter concept from the previous section to clinical audiogram design.”
• Short sound durations necessarily produce broad frequency bandwidths. — Introduces the time-frequency tradeoff, a foundational psychoacoustic concept.
• A pure tone’s peak amplitude is the maximum pressure it achieves per cycle. — Defines peak amplitude/peak pressure as the single amplitude value characterizing a pure tone.
• Peak amplitude misrepresents complex sounds with varying amplitude — Clarifies when peak amplitude is inadequate and motivates the need for rms measures.
• Time and frequency representations are linked so short durations broaden bandwidth — The time-bandwidth reciprocity (uncertainty relation) stated in accessible terms — foundational for understanding masking and frequency resolution in impaired hearing.
• The ear analyzes frequencies by location along the basilar membrane. — Tonotopic organization explained concretely via basilar membrane base-versus-apex mapping.
• Outer hair cells respond better than inner hair cells to low-frequency sound — Cleanly partitions the outer (mechanical amplifier) and inner (transducer) hair cell roles — the core functional division of the cochlea.
• Auditory nerve fibers’ thresholds correlate inversely with their spontaneous firing rates. — Defines neural threshold as the lowest sound level producing a measurable increase in driven spike rate.
• Auditory nerve fibers divide into three types by spontaneous firing rate. — Defines neural saturation and lays out the three-fiber classification scheme.
• Hearing thresholds were first systematically mapped in the 1930s using two distinct measurement paradigms — Defines MAF versus MAP as the two classic absolute-threshold measurement paradigms, distinguished by free-field binaural versus headphone monaural presentation.
• Outer hair cell loss reduces hearing sensitivity by up to 60 dB — Distinguishes the functional roles of outer vs inner hair cells — a core concept for understanding sensorineural hearing loss types.
• 95 percent of auditory nerve fibers carry coded signals from inner hair cells upward — Defines type I fibers and their synapse targets; foundational for neural coding topics.
• The shape of the audiogram reflects outer and middle ear transfer, not cochlear transmission — Clarifies why the audiogram valley exists — a mechanism-level explanation of normal hearing sensitivity.
• Auditory nerve fibers’ thresholds correlate inversely with their spontaneous firing rates. — Names the specific fiber class responsible for encoding faint sounds — core mechanistic detail for the reader’s goal.
• Middle-ear stiffness increases cause low-frequency hearing loss — Concise clinical definition of otosclerosis and the acoustic mechanism (stiffness-based) behind its early-stage hearing loss.
• Adaptive procedures converge on thresholds without explicit psychometric functions — Defines the psychometric function and states why adaptive procedures require it.
• Some false positives during threshold testing indicate healthy response bias — Explains what a false positive reveals about a patient’s internal response criterion during threshold testing.
• Thresholds are statistical detection probabilities, not absolute cutoffs — Clarifies that ‘threshold’ is a probabilistic detection level, overturning the intuitive all-or-nothing picture.
• Psychometric functions map continuous stimulus scales onto probabilistic detection judgements — Defines the psychometric function and the yes/no task that generates it.
• Self-adjustment threshold methods are fast but lack a standardized response criterion across listeners. — Characterizes the method of adjustment: no fixed percent-detection definition, criterion dependence, but still used for subjective percepts.
• The method of constant stimuli needs prior knowledge of testable levels — Introduces the method of constant stimuli as one classical psychophysical threshold procedure.
• Clinical threshold testing uses undefined observation intervals to prevent anticipation from lowering thresholds. — Defines the undefined observation interval and its purpose.
• Staircase rules specify how many correct trials precede a level decrease — Defines the 2-down 1-up and 3-down 1-up staircase rules and introduces the concept of reversals.
• Adaptive staircases track a listener’s responses to set signal level — Defines adaptive staircase methods, citing Levitt 1971, and contrasts them with clinical Hughson-Westlake.
• Forced-choice paradigms present one signal amid two or more observation intervals. — Defines the forced-choice paradigm structure underlying psychophysical threshold estimation.
• Threshold estimates reflect both ear sensitivity and listener response bias — Defines response bias vs. auditory sensitivity — a core distinction for anyone measuring thresholds.
• Signal detection theory models signals and noise as two probability distributions — Defines the foundational signal detection theory framework of two internal-response distributions.
• In signal detection theory, threshold responses depend on an internal response criterion reflecting bias. — Introduces the criterion concept that separates sensitivity from response bias.
• Standard clinical threshold testing estimates the 85-95% detection point — Explains the 10-down/5-up adaptive procedure mechanics and its detection-convergence percentage.
• Threshold from up-down staircases is the averaged level at response reversals. — Explains the up-down staircase decision rules and defines ‘reversals’ as the response-turn points that threshold is averaged from.
• Response bias distorts threshold measurements in hearing experiments. — Defines response bias as the listener’s tendency to say ‘yes I heard something,’ distinct from sensitivity.
• Masking experiments revealed the auditory filter underlying frequency selectivity — Defines frequency selectivity and the auditory filter concept directly relevant to how impaired ears differ.
• Energetic and informational masking operate through distinct peripheral and central mechanisms — Defines the energetic/informational masking dichotomy, a foundational conceptual framework for the whole field.
• The excitation pattern is the internal representation of a stimulus spectrum — Defines one of the chapter’s core models: the excitation pattern.
• Masking depends on acoustic relationships between masker and signal, not on subjective noise. — Clarifies that ‘noise’ in psychoacoustics means any sound defined acoustically, not ‘unwanted sound’.
• White noise carries constant power per hertz across the human hearing range — Defines white noise acoustically: flat power spectrum from 20 to 20,000 Hz within hearing science.
• White noise amplitude is described by total power or spectrum level (LPC). — Defines the two amplitude metrics for noise: total power and spectrum level/LPC per 1-Hz band.
• Narrowband noise needs bandwidth and center frequency descriptors — Defines narrowband noise and the parameters (bandwidth, center frequency) that fully describe it.
• Hearing loss acts like a filter attenuating specific frequencies — Introduces filters as the core building block of auditory perception models, linking physics to hearing impairment.
• Two noises with equal LPC differ in total power by their bandwidth — Clarifies that LPC is bandwidth-dependent for physical noise while dB SPL applies only to physical, not perceptual, representations.
• Noise is defined relationally against the signal rather than acoustically — Clarifies that ‘noise’ in psychoacoustics is a relational concept, correcting the colloquial ‘unwanted sound’ definition.
• Masking occurs when one sound interferes with perceiving another — Gives the core definition of masking and its three distinguishable scopes (detection vs. discrimination vs. recognition).
• White noise has flat power across the 20 to 20,000 Hz hearing range — Defines white noise by its flat power spectral density and assumed hearing-range bandwidth.
• Filter cutoff frequency is conventionally the 3-dB-down point. — Defines the technical meaning of cutoff frequency as the 3-dB-down boundary, not where attenuation first begins.
• A filter’s transfer function describes gain in dB independent of sound level. — Clarifies what a transfer function is and why filter gain (dB) is distinguished from the sound’s own dB SPL level.
• Tuning curves map the lowest level that evokes neural or basilar response — Defines the tuning curve concept and how it’s measured at both the basilar membrane and auditory nerve levels — core methodology for the reader.
• Band-pass filters are specified by either two cutoffs or center frequency plus bandwidth — Clarifies filter specifications — cutoff frequencies vs center frequency plus bandwidth — foundational vocabulary for noise generation in psychoacoustics.
• Similar frequencies mask each other by competing for the same cochlear location. — Explains the mechanism behind masking: place-on-basilar-membrane competition, tying physiology directly to the perceptual phenomenon.
• Masking experiments infer auditory representation from masker effects on signals. — Defines signal vs masker and why the masking paradigm is used for inference.
• Masking is quantified as the threshold shift between unmasked and masked conditions. — Defines the standard two-condition masked/unmasked measurement protocol and the 2I-2AFC masking trial design.
• Hawkins and Stevens measured broadband-noise masking of pure tones across eight masker levels. — Classic 1950 result anchoring quantitative masking data; foundational for subsequent masking models.
• Frequency selectivity is the auditory system’s ability to represent one frequency independently of another. — Defines frequency selectivity and distinguishes its perceptual from physiological sense.
• Amount of masking is expressed as a decibel difference, not an absolute SPL level — Clarifies the crucial distinction between dB as an absolute reference level and dB as a difference measure — a common point of confusion.
• Masking patterns reveal the ear’s internal psychological representation of a sound. — Defines the ‘masking pattern’ concept as a psychological representation of an acoustic stimulus — a core model the reader explicitly wants.
• Conductive hearing loss can be modeled as a filter, but sensorineural loss cannot — Clarifies how filter transfer functions describe ear and hearing-loss behavior, distinguishing conductive from sensorineural cases.
• Masking is quantified as the threshold shift between unmasked and masked conditions. — Defines simultaneous masking and the masked vs unmasked threshold paradigm that anchors most masking experiments.
• Three acoustic properties determine whether a sound masks another. — Frames the chapter’s organizing scheme: intensity, frequency content, and temporal characteristics as the masking determinants.
• Masking patterns reveal the ear’s internal psychological representation of a sound. — Introduces the masking pattern as a psychological/internal representation of the masker — a foundational concept for how psychoacousticians infer internal representations from behavioral thresholds.
• Only masker power within the critical band around a signal affects its threshold — Explains the mechanism by which frequency selectivity limits which maskers affect a signal.
• The notched-noise method directly measures auditory filter shape. — Explains the notched-noise method for estimating auditory filter shape, a key technique.
• The notched-noise method directly measures auditory filter shape. — Explains the computational estimation method for auditory filters via the power spectrum model.
• ERB is the standard metric for auditory filter bandwidth — Defines equivalent rectangular bandwidth and contrasts it with 3-dB down points.
• Only low-numbered harmonics are resolved, higher ones blur together in the internal representation — Establishes the resolved/unresolved harmonics distinction, basic auditory science vocabulary.
• The excitation pattern plots auditory-filter output power against filter center frequency — Defines the excitation pattern as the internal (as opposed to acoustic) representation of a sound, built from auditory-filter outputs.
• There is a critical bandwidth beyond which adding noise power no longer increases masking — Introduces Fletcher’s concept of the critical band, a foundational idea in psychoacoustics.
• The band-widening paradigm measures signal threshold while varying masker bandwidth — Clarifies the experimental logic distinguishing Fletcher’s band-widening method from Egan and Hake’s fixed-masker method.
• Masking effectiveness depends only on masker power inside the critical band. — Defines the power spectrum model of masking, a core concept the reader explicitly wants in models and theories.
• The notched-noise method directly measures auditory filter shape. — Explains the iterative fitting procedure behind auditory filter estimation, a core methodological concept.
• ERB is the standard metric for auditory filter bandwidth — Defines the ERB metric for auditory filter width, a routinely used psychoacoustic term.
• The ear’s frequency resolution worsens progressively at higher frequencies. — The excitation pattern is a running representation of the spectrum; this passage defines what it does — smoothing the spectrum via the ear’s imperfect filters.
• Listeners benefit from spectral profiles bandwidth-wide yet do not use all available spectral information — Introduces and defines profile analysis — a core concept the reader asked for.
• Forward masking reveals an effect that only appears when sounds co-occur. — Contrasts simultaneous versus forward masking paradigms as experimental tools.
• Fluctuating maskers produce masking release that Fletcher’s power spectrum model cannot explain. — Defines the ‘fluctuating masker benefit’ as the threshold difference between steady and fluctuating maskers.
• Loss of cochlear suppression explains similar PTCs across masking conditions. — Explains the suppression mechanism and how forward vs. simultaneous masking distinguishes it — a core concept for the reader’s theory-of-hearing goal.
• Cross-hearing via bone conduction can contaminate thresholds, requiring masking in audiometry. — Defines cross-hearing and clinical masking in one compact explanation.
• A masker only shifts thresholds that already lie below its EML. — Concrete worked example clarifying what dB EML means in practice.
• A worked dB EML example shows masking calculations in practice. — Concrete numeric application of the dB EML formula the reader explicitly requested.
• Listeners use distributed spectral information but not all of it — Defines profile analysis as measuring discrimination of spectral envelope shapes across frequency.
• Spectral valleys contribute little to vowel identification compared with formants — Clarifies that excitation-pattern masking experiments isolate which spectral components carry perception.
• Psychophysical tuning curves measure frequency selectivity via tone-on-tone masking. — Explains the psychophysical tuning curve technique and how it builds a tuning curve from masker-level data.
• Normal-hearing listeners exploit temporal dips in fluctuating maskers to detect signals. — Introduces the concept of ‘dip listening’ and the dips/valleys vocabulary that structures the whole masking-release literature.
• Clinical maskers must be wider than the critical band to work — Defines effective masking level (dB EML) as the dB HL to which threshold shifts under a noise.
• Loudness is a psychological percept measurable only through human report — Core conceptual definition — loudness is unmeasurable directly and requires human listeners, unlike physical intensity.
• Intensity is directly quantifiable acoustically while loudness requires human listeners — Clarifies why loudness and intensity are not interchangeable terms and how measurement differences shape data interpretation.
• Sound pressure and intensity are distinct quantities interconvertible by a known relationship — Clarifies the technical distinction between sound pressure (force per area) and intensity (power per area).
• Reaction time spans the full hearing range where psychometric functions cover only 10-15 dB — Defines reaction time as a psychoacoustic measure and distinguishes it from the ceiling-limited psychometric function.
• Weber fractions in audition are computed from intensity, not decibels — Defines how the Weber fraction is computed for intensity discrimination: JND is the intensity difference, the fraction is that difference divided by the baseline intensity.
• Intensity discrimination improves with level for tones, violating Weber’s law — Introduces and defines the ‘near miss to Weber’s law’ — a core concept in loudness perception.
• Near-threshold sounds may sound louder to impaired than to normal ears — Defines ‘softness imperception’ — the surprising finding that SNHL listeners hear near-threshold sounds as louder, not softer.
• Sensorineural hearing loss compresses the full loudness range into fewer decibels — Defines ‘loudness recruitment’ — listeners with SNHL experience the full loudness range compressed into a smaller dB span.
• The full loudness range squeezes into a smaller dynamic range for impaired listeners. — Explains the mechanism by which recruitment produces steeper loudness-growth slopes.
• Severe hearing loss from inner hair cell loss reduces maximum loudness — Defines underrecruitment/partial recruitment in contrast to loudness recruitment.
• Hyperacusis is a separate pathology from sensorineural hearing loss — Distinguishes hyperacusis from SNHL and notes its frequent association with tinnitus.
• Loudness discomfort levels are measured to fit hearing aids and assess hyperacusis — Defines LDLs and their dual clinical role.
• Hearing-impaired listeners show faster loudness growth but similar discomfort thresholds — Defines how loudness is measured (rating vs. matching) and their distinct inferential uses.
• The term UCL fits the measurement better than LDL, yet US practice favors LDL — Clarifies the overlapping terms LDL, UCL, ULL, and TD and which best matches the measurement.
• Clinical LDL testing uses categorized loudness scaling with ascending stepped levels — This is the operational definition of how an LDL is obtained, tying abstract concept to concrete procedure.
• Sensorineural hearing loss causes abnormal rapid loudness growth called recruitment — Defines recruitment as rapid loudness growth in sensorineural hearing loss and attributes it to outer hair cell loss.
• Wider bandwidth increases perceived loudness at equal sound pressure — Defines spectral loudness summation and the near miss — both key concepts for understanding loudness perception.
• Magnitude estimation lets listeners assign numbers proportional to perceived loudness. — Defines magnitude estimation and the loudness growth function it produces.
• Stevens anchored the sone unit to a 1000-Hz tone at 40 dB SPL. — Defines the sone, the fundamental unit of loudness, via its reference stimulus.
• Stevens had to invent both the tools and the unit for measuring loudness — Sets up the sone unit and magnitude estimation described immediately after.
• Loudness grows as a power law of intensity, not linearly. — Introduces Stevens’ power law relationship between loudness and intensity.
• The loudness-intensity relationship is named Stevens’ power law. — Names and defines Stevens’ power law, the central model of this chapter.
• Loudness coding requires pooled responses across many auditory nerve fibers — Clarifies how the auditory code for loudness works across a population of fibers rather than within a single fiber.
• The phon scale defines loudness relative to equal-loudness matches at 1 kHz — Defines the phon: loudness level in phons equals the dB SPL of a matching 1000-Hz tone.
• Categorical loudness scaling measures uncomfortable and comfortable loudness levels using verbal categories — Defines categorical loudness scaling and its clinical use for UCL and MCL measurement.
• Loudness balancing measures loudness by matching a test sound’s level to a reference — Defines the loudness balancing/matching procedure as adjustment-based rather than rating-based.
• Outer and middle ear damage changes the loudness frequency balance — Introduces dB A weighting as built on the 40-phon contour; key applied metric.
• A sound’s bandwidth independently affects how loud it sounds. — Introduces ‘spectral loudness summation’ as the term for bandwidth’s effect on loudness.
• Sound level meters measure pressure, from which intensity is derived — Precision point on what a sound level meter physically captures.
• Intensity discrimination measures the smallest detectable change in loudness — Defines the just noticeable difference (JND) and difference limen as central intensity perception measures.
• Near miss to Weber’s law occurs for tones but not noise — Defines the ‘near miss to Weber’s law’ and specifies the tone vs noise condition boundary.
• Recruitment can explain why loudness summation is absent in noise-induced hearing loss — Introduces and names loudness recruitment, a core term for the reader’s stated interest in hearing perception.
• Hearing-impaired listeners show faster loudness growth but similar discomfort thresholds — Distinguishes rating vs matching measurement as the basis for separate inferences about loudness growth vs frequency effects.
• Stevens defined one sone as a 40 dB SPL 1000-Hz tone — Defines the sone, the fundamental unit of loudness.
• Magnitude estimation lets listeners assign numbers proportional to perceived loudness. — Defines magnitude estimation and the loudness growth function concept central to loudness scaling.
• Loudness is measured either by rating magnitude or by matching equal loudness — Establishes the two foundational experimental approaches to loudness measurement and which question each answers.
• Magnitude estimation of loudness yields only relative, not absolute, values. — Clarifies how the sone scale works as a ratio/relative measure rather than an absolute one.
• Loudness grows faster at low levels than Stevens’ power law predicts — Clarifies the well-known exception to Stevens’ power law that students of loudness must know.
• Categorical loudness scaling uses labeled bars from Not Heard to Too Loud — Defines categorical loudness scaling as a no-reference rating method using verbal categories, contrasted with matching procedures.
• Gap added to a tone creates audible spectral splatter or side lobes. — Explains why white noise is used in gap detection experiments despite the logic of the task.
• Auditory stimuli separate into fine structure and slower envelope — Defines temporal fine structure/carrier versus envelope/modulator as the two time-dependent stimulus aspects.
• Gap detection measures the smallest audible silent gap — Defines gap detection as measuring the just-noticeable duration of a silent gap.
• Gap detection measures the smallest audible silent gap — Defines temporal resolution assessment via gap detection.
• Temporal processing is essential for hearing speech and music — Defines temporal processing as the representation of intensity variations over time.
• Temporal fine structure is vital yet not perceived as a temporal event — Clarifies that temporal fine structure, despite its importance, is excluded from temporal processing because it is not perceived as a temporal event.
• Sounds are time-varying when their intensity changes over time — Defines steady versus time-varying sounds by whether intensity remains constant.
• A sound must decay enough before a following sound stops fusing with it — Explains the mechanism linking auditory persistence to temporal fusion.
• Brief quiet gaps in sounds can introduce spectral cues that contaminate gap detection results — Crucial methodological distinction: gap detection measures genuinely temporal processing only when spectral cues are absent.
• Inserting a temporal gap into a stimulus produces spectral splatter at the gap edges — Defines spectral splatter and its source in the time-frequency trade-off, connecting temporal processing to the uncertainty principle.
• Elevated gap detection thresholds in hearing loss stem from threshold elevation, not temporal pathology — Explains the confound: elevated threshold from hearing loss can mask a genuine temporal-processing deficit.
• Gap detection improves with bandwidth because the ear listens across more auditory filters — Explains the multi-filter listening model that would later underpin models of across-channel summation in temporal processing.
• Gap detection measures only on-off sensitivity, not coding of fluctuation rates. — Clarifies the scope and limits of gap detection as a measure of temporal resolution.
• Temporal order thresholds exceed gap detection because listeners must hold sound identities in memory — Distinguishes gap detection from temporal ordering as separate experimental paradigms.
• Narrowband noises fluctuate more than wideband stimuli, making them useful for studying fluctuation coding — Defines narrowband noise and its fluctuation properties relative to wideband noise.
• Narrowband noise’s natural waveform fluctuations mask the presence of inserted gaps — Concrete illustration of how intrinsic waveform fluctuations (valleys vs peaks) physically interact with an inserted gap.
• Amplitude-modulated sounds split into slow-varying envelope and fast-varying fine structure — Defines envelope/modulator versus fine structure/carrier in amplitude-modulated sounds.
• Modulation depth m ranges from unmodulated to fully modulated sounds — Defines the modulation depth parameter m and clarifies that even steady tones carry an envelope.
• The auditory system represents modulations below 55 Hz well and worse above — Specifies the TMTF cutoff frequency of 55-65 Hz, a quantitative anchor for temporal resolution.
• Forward masking requires maskers with similar frequency components and high intensity — Names ‘release from forward masking’ as the threshold decrease with growing separation.
• Temporal order thresholds exceed gap detection because listeners must hold sound identities in memory — Distinguishes temporal ordering experiments from plain gap detection tasks.
• Narrowband noises contain fewer frequencies and show greater amplitude fluctuations than broadband noise. — Introduces narrowband noise as a tool for probing slow-fluctuation representation.
• Amplitude modulation below about 60 Hz is well represented in hearing — The TMTF cutoff frequency is the auditory representation bandwidth for modulation rates.
• The ear integrates energy over time to lower detection thresholds for longer sounds — Defines temporal integration/summation as distinct from temporal resolution.
• Temporal integration models divide on time constant assumptions of hundreds versus single-digit milliseconds. — Defines the two competing classes of temporal integration models in terms of their time constants, which is central to the reader’s goal of cataloguing hearing models.
• The auditory system can discard uninformative temporal information during detection — Defines the multiple looks hypothesis against classic energy detection.
• Hearing loss reduces audibility and restricts usable bandwidth for temporal processing — Explains the mechanism by which hearing loss confounds temporal processing measurement.
• Comparing hearing-impaired and normal listeners requires controlling for both sensation level and absolute level — Explains the experimental-limitation logic behind ‘apples to apples’ comparisons in hearing psychophysics — core methodology for reader’s goal.
• Hearing loss reduces audibility and restricts usable bandwidth for temporal processing — Shows the research method of simulating hearing loss with a noise masker to isolate the temporal integration deficit from audibility loss.
• Temporal processing of sound has three distinct measurable categories. — Provides the reader’s requested conceptual framework for the three categories of temporal processing.
• Not all sounds have a pitch even though all have frequency content — Distinguishes the perceptual attribute pitch from the acoustic property frequency.
• Pitch is formally defined as where sounds fall on a musical scale — Gives the ANSI definition of pitch plus an intuitive gloss useful for teaching.
• Harmonic tones are integer multiples of a fundamental frequency — Defines harmonic sounds and the fundamental frequency in acoustic terms.
• Pitch perception involves both spectral and temporal representations of sound — Defines the place code vs temporal code dichotomy that structures all of pitch perception theory.
• Harmonic amplitudes shape timbre and loudness but not pitch. — Clarifies the pitch-vs-timbre division that hearing-impaired perception and hearing aid tuning hinge on.
• Helmholtz’s place theory says pitch derives from the basilar membrane’s location of maximum excitation. — Lays out the classical Helmholtz place theory of pitch, the baseline model the rest of the chapter tests against.
• Period histograms visualize neural firing synchrony by spike phase — Defines the period histogram, a core tool for visualizing phase locking in auditory nerve research.
• The auditory system can extract pitch from resolved low-frequency harmonics using place patterns — Explains what ‘resolved harmonics’ means and why resolution degrades with frequency — a core distinction in pitch perception.
• Auditory frequency is encoded by both place and temporal codes. — Concise summary definition of the two fundamental neural codes for frequency.
• Pitch perception involves both spectral and temporal representations of sound — Introduces the spectral-temporal code concept — a hybrid of place and temporal theories that the reader explicitly asked for as a ‘model’.
• Pitch can be derived from harmonic spacing even without the fundamental present. — Introduces the two spectral routes to f0 and the GCF concept, foundational to later ‘missing fundamental’ material.
• Pitch arises from where along the cochlea a sound maximally stimulates — Establishes the core definition of the place code and its two forms: simple (Helmholtz peak location) and pattern-based (harmonic peaks).
• Across-filter neural synchrony provides a robust pitch code — Defines across-frequency autocorrelation as the psychophysical model capturing temporal synchrony across frequency bands.
• Pitch has no magnitude like loudness, so magnitude scaling misapplies to it. — Clarifies pitch strength and pitch chroma as components the mel scale ignores.
• The mel scale defines pitch by assigning 1000 mels to a 1000-Hz tone — Defines the mel as a unit of perceived pitch, anchored to 1000 Hz.
• Sensorineural hearing loss worsens diplacusis, which even normal hearers have mildly — Defines diplacusis clearly as hearing the same physical tone at different pitches in each ear, along with its measurement method.
• Pitch strength is a distinct perceptual dimension absent from loudness — Defines pitch strength as an independent perceptual dimension with a specific measurement method, contrasted explicitly against loudness.
• The residue pitch refuted Helmholtz’s place theory of pitch percept. — Defines residue pitch and the pitch of the missing fundamental, the key term introduced here.
• Pitch of harmonic sounds is determined by the fundamental frequency. — Establishes the core observation that pitch of complex tones tracks fundamental frequency.
• The existence region supports a place-based harmonic template model of pitch — Defines the harmonic template model (a variant of the place model) and shows how it explains residue-pitch existence regions — precisely the theory/model content the reader asked for.
• Temporal codes yield weak pitches compared to place codes — Introduces pitch strength as a measurable quantity anchored to a 250-Hz reference tone — a useful methodological model.
• Auditory nerve phase locking can encode slow waveform fluctuations across filters — Introduces across-frequency autocorrelation as the model capturing temporal synchrony in pitch.
• Physiological measures alone cannot prove how pitch perception works — Methodological point — physiological evidence requires behavioral corroboration because physiology does not assess perception directly.
• Pitch may be jointly coded by temporal patterns and their cochlear location — Defines the place code and temporal code as the two core pitch-perception models and their frequency dominance.
• Hearing loss disrupts pitch perception through multiple independent coding failures — Introduces diplacusis as a cross-ear pitch asymmetry symptom arising from hearing loss.
• Place and temporal codes each offer distinct neural mechanisms for extracting pitch — Concise definitions of the two rival pitch-perception codes.
• Modern pitch research relies on discrimination tasks because subjective pitch ratings are problematic — Introduces 2I-2AFC and adaptive staircase as the standard psychophysical procedures behind pitch measurement.
• Random intensity variation disrupts place but not temporal pitch coding — This is the experimental logic that distinguishes place from temporal code: intensity variations spare timing cues but corrupt place cues.
• Level-dependent frequency discrimination contradicts a purely temporal pitch code — Clarifies what phase locking does and does not track (rate is intensity-independent; synchrony across channels is what varies).
• Missing fundamental pitch survives even when cochlear distortion is masked out — Defines residue pitch / pitch of the missing fundamental and its historical proof.
• Resolved low-numbered harmonics are required to encode pitch by place — Clarifies the harmonic template model and its requirement that components be resolved to extract pitch.
• Resolved harmonics use place pitch coding while unresolved harmonics use temporal coding — Explains the place vs temporal mechanism distinction and which applies depending on harmonic resolvability.
• Headphone experiments measure binaural summation by stimulating each ear independently — Defines binaural summation as the ability to use information from both ears to improve performance, distinct from free-field binaural effects.
• Binaural summation gives a consistent two-ears vs one-ear benefit — Introduces the concept of binaural summation and its dependence on symmetric hearing.
• Sound location is mapped with azimuth and elevation coordinates — Nail-down definitions for azimuth and elevation in head-related coordinates.
• Head shadow attenuates sound arriving at the far ear unless the source is centered — Defines head shadow, the intensity reduction at the ear distant from a source, and its geometry.
• High-frequency sounds reflect off the head while low-frequency sounds diffract around it — Introduces wavelength equation (c/f) and the reflect-versus-diffract mechanism that underlies head shadow.
• Interaural level differences grow with frequency and side placement — Defines interaural level difference (ILD) as the dB difference between the two ears and gives its measured frequency/azimuthal behavior.
• ITDs are frequency-independent physically yet frequency-dependent perceptually. — Frames the key distinction between physical ITD and its perceptual availability by frequency, prefiguring the phase-ambiguity problem for high frequencies.
• High-frequency tones produce ambiguous azimuthal localization due to phase wrapping. — Concretely demonstrates IPD ambiguity via phase wrapping at frequencies above the head-shadow ITD limit.
• All sound locations sharing one ITD form an infinite cone of confusion — Introduces the cone of confusion concept central to localization limits.
• Experiments isolating two-ear advantages must present stimuli over headphones — Defines monotic, diotic, and dichotic stimulus conditions — core vocabulary for the binaural hearing literature.
• Rayleigh first proposed ILDs code high frequencies and ITDs code low frequencies — Defines the two fundamental binaural cues, ILD and ITD, and a named origin (duplex theory of localization).
• Interaural phase difference varies with frequency while interaural time difference does not — Distinguishes ITD from IPD and explains their mathematical relation.
• Head movements and pinna shape resolve ambiguous sound localization — Clarifies what the cone of confusion is and what breaks it — a key model concept.
• The lateral superior olive compares ear intensities via excitation and inhibition — Explains the neural mechanism (ipsilateral excitation, contralateral inhibition) the LSO uses to encode ILD.
• The just-detectable speaker shift defines the minimum audible angle. — Defines MAA operationally as the threshold angle for detecting a change in speaker location.
• Separating a signal from a competing noise location aids detection beyond diotic summation — Defines diotic versus dichotic presentation and states why real-life listening is dichotic.
• Head-related transfer functions encode all body-induced spectral and temporal sound changes — Defines HRTF as the unifying three-dimensional function for body-influenced acoustic changes.
• Separating signal from masker locations improves detection through two binaural effects — Introduces the taxonomy of binaural unmasking effects: better-ear advantage and binaural squelch.
• Inverting signal phase at one ear vastly releases speech from masking. — Introduces homophasic versus antiphasic stimulus configurations central to the binaural masking level difference paradigm.
• The first arriving sound wave dominates perceived localization regardless of level — Defines the precedence effect and names its originators with the 1949 citation.
• Pinnae shape the sound spectrum to encode elevation and front-back position — Explains the pinnae-based spectral mechanism for median-plane localization, a core concept for understanding 3D hearing acoustics.
• The auditory system lacks robust access to interaural phase above 1000 Hz — Establishes the key functional limit: interaural phase coding is only robust below about 1000 Hz.
• Speech understanding benefits when the signal is phase-inverted at one ear. — Introduces and explains the homophasic vs antiphasic experimental manipulation.
• Three distinct perceptual phenomena define the precedence effect. — Defines the three component phenomena of the precedence effect.
• Degraded interaural timing coding, not audiometric asymmetry, explains reduced MLD in hearing loss. — Clarifies that MLD is a binaural release from masking, and distinguishes the audiometric-asymmetry explanation from the interaural-timing explanation.
• Restoring audibility does not restore sound localization in hearing loss — Defines precedence effect and its role with binaural unmasking.
• Two ears yield summation, localization, and echo suppression jointly — Summarizes the core binaural abilities (summation, duplex localization, masking reduction, precedence effect) as an organizing framework.
• Low-level auditory deficits cascade upward to impair speech comprehension — Introduces Erber’s hierarchy of perception: detection, discrimination, recognition, comprehension.
• Elevated hearing thresholds degrade speech perception by rendering key cues inaudible — Introduces auditory scene analysis and how robust audibility supports sound segregation—a usable definitional anchor.
• Loudness recruitment makes raised speech feel too loud even without abnormal sound perception — Defines loudness recruitment as abnormally rapid growth of loudness, a core clinical concept for the reader’s purposes.
• Alternate binaural loudness balancing plots recruitment as non-parallel laddergram rungs — Explains the ABLB method and laddergram reading, core to understanding how recruitment is clinically measured.
• A missing audiometric shadow curve reveals feigned (non-organic) hearing loss. — Explains what an audiometric shadow curve is and why its absence signals pseudohypacusis.
• Rollover signs make loud amplification harmful to retrocochlear patients — Introduces the performance-intensity (PI) function, a plot of speech performance against presentation level.
• Binaural sound lateralizes to the ear receiving the louder signal — Defines the Stenger test and its underlying lateralization principle.
• Auditory processing disorder is a contested diagnosis lacking a single-locus definition — Defines central auditory processing disorder as a central-pathway condition distinct from peripheral and cognitive pathology.
• Central auditory processing diagnosis requires exclusionary peripheral and cognitive tests — Defines the diagnostic logic for APD — which tests rule out pathologies vs. which tests are core and informative.
• Hearing-impaired listeners show intact gap detection but prolonged forward masking that hides consonants — Clarifies the distinction between transient measures (gap/modulation detection, largely intact) and sustained forward-masking/temporal-integration measures (profoundly impaired).
• Raising speech level reduces the advantage from masker fluctuation absence — Explains what ‘fluctuating masker benefit’ means and why recruitment erodes it.
• Pitch cues convey identity, intonation, and emotion beyond mere speech content — Enumerates the non-content functions of pitch in speech that hearing loss strips away.
• Hearing loss is a sensory-representation deficit, not merely an acoustic one. — Sharp definitional distinction: hearing loss is supra-threshold representation deficit, not simple attenuation — this reframes why amplification is insufficient.
• Tinnitus has no objective diagnostic test and is diagnosed by self-report alone — Defines tinnitus as ‘the perception of a sound in its absence’ and describes its attributes (loudness, timbre, pitch).
• Speech intelligibility depends on which frequency bands matter for specific materials. — Explains how the Speech Intelligibility Index weights frequency bands and how count-the-dot audiograms visualize audible speech.
• Loudness recruitment makes raised speech feel too loud even without abnormal sound perception — Frames loudness recruitment (abnormally rapid loudness growth in sensorineural hearing loss) in practical conversational terms.
• Audibility deficits must be corrected before supra-threshold factors can be studied. — Clarifies the distinction between audibility and supra-threshold auditory deficits, a foundational clinical-analytic split.
• ABLB laddergram rung divergence reveals whether loudness grows faster in an impaired ear — Describes the laddergram tool used to visualize recruitment and its absence.
• Auditory processing disorder is a contested diagnosis lacking a single-locus definition — Defines APD as a central-auditory-pathway disorder distinct from peripheral and cognitive pathologies.
• Hearing loss is a sensory-representation deficit, not merely an acoustic one. — Distinguishes acoustic deficits (fixable by amplification) from sensory-representation deficits, explaining why the glasses analogy fails.
• Processing spectral peaks and valleys in separate compression channels erases their level difference — Explains the channel-count versus compression interplay that defines why WDRC channel number matters.
• Tinnitus is the top service-connected military disability yet lacks any diagnostic test. — Gives the operational definition of tinnitus as perception of sound in its absence while flagging its exclusively self-report diagnosis.