Masking depends on the masker’s acceleration, not its amplitude.

Evidence

These three data sets indicate that the masking-period pattern’s time dependence cannot always be directly related to the masker’s time function. However, it is obvious that positive values of the second derivative of the masker’s time function seem to play the dominant role in producing masking-period patterns of tone bursts masked by periodical low-frequency maskers. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 584

Categorization

• XREF: Connects to the physical principle that acceleration (not displacement or velocity) is the effective stimulus for hair-cell mechanotransduction.
• QUESTION: Why would the second derivative dominate — is this pointing at nonlinear cochlear mechanics downstream of mere basilar-membrane displacement?