Perceptual thresholds blur because listener internal noise varies by personality

Evidence

The mapping of a physical quantity onto an auditory quantity is thus binary, either the value of h is above or below the threshold, as discussed in relation to Figure 8.1. However, the mapping does not change abruptly near the threshold, there is always a region where the auditory event may or may not be formed. This depends on some internal state of the subject, such as the level of inherent noise in sensory systems. When a listening test is organized and subjects are asked whether they perceive the auditory event, the description function bo = f(hi) also comes in to play. For example, the personal character of the listener may have a large influence on the description, as typically some subjects tend to perceive auditory events although there are no sound events, and other subjects are more insecure and report an auditory event only when it is very clearly audible. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 886

Categorization

• DEFINE: Introduces the psychoacoustic threshold as a probabilistic region, not a hard cutoff.
• XREF: Connects to signal detection theory’s distinction between sensitivity (d’) and response bias (criterion). — connects to: Noise-sensitive people differ physiologically and psychologically from non-sensitive ones — Almo Farina, Soundscape Ecology: Principles,…, 925