Loudness constancy requires ecologically valid, multisensory real-world stimuli

Evidence

Epstein and Florentine ( 2009 , 2012 ) conducted similar tests, but using standard loudness estimation procedures and speech (spondees) either with or without accompanying video of the speaker’s face. They also observed loudness constancy, but only when using the audiovisual presentation. Their tentative conclusion was that loudness constancy may only occur using stimuli of relatively high ecological validity. Ecological validity may be enhanced when an external source is used, when that source is speech, particularly connected speech rather than isolated words, and when accompanied by coherent visual cues. Since all these conditions are fulfilled when listening to someone in real life, the phenomenon of loudness constancy can be compellingly, if informally, demonstrated by simply occluding one ear with a finger when listening to someone talk; most people report that no change in loudness is apparent. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1529

Categorization

• CANDY: The finger-in-ear demo during conversation showing no loudness change is a delightful party trick that sounds counterintuitive.
• SEED: The case for an article: standard lab findings about binaural loudness summation may not reflect real-world perception — an instance of low ecological validity distorting a foundational psychophysical result.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1529