Categorical loudness data is probabilistic, not reducible to a median response curve.

Evidence

A listener’s CLS function, generally computed from the median stimulus level for each response category, is the measure typically used in analysis. This standard approach treats the variability in the response data as something to be removed. We propose to instead model the probabilistic nature of listener responses; these probabilistic representations can be used to improve loudness measurements and further our understanding of the mechanisms underlying this perception. At each stimulus level, there is a probability distribution across categorical loudness responses; when plotted as a function of stimulus level, these distributions form a multi-category psychometric function (MCPF), modeling the statistics of the listeners’ categorical perception. — Dijk, Pim van, Physiology, Psychoacoustics and…, 2515

Categorization

• DEFINE: Introduces the multi-category psychometric function (MCPF) as a probabilistic alternative to the standard categorical loudness scaling function.