Duration perception of time-varying sounds: The role of the amplitude decay and rise-time modulator

Abstract

It is well known that ramped (rising energy) sounds are perceived as longer in duration than damped (falling energy) sounds that are time-reversed, but otherwise identical versions of one another (Schlauch, Ries & DiGiovanni, 2001; Grassi & Darwin, 2006). This asymmetry has generally been attributed to the under-estimation of damped sound duration, rather than the over-estimation of ramped sound duration. As previous literature most commonly employs exponential amplitude modulators, in the present experiment, we investigate whether altering the nature of this amplitude decay- or rise-time modulator (linear or exponential) would influence this typically observed perceptual asymmetry. Participants performed an adaptive, 2AFC task that assessed the point of subjective equality (PSE) between a standard tone with a constant ramped/damped envelope, and a comparator tone with a “flat,” steady state envelope whose duration varied according to a 1-up, 1-down rule. Preliminary results replicated previous findings that ramped sounds are perceived as longer than their time-reversed, damped counterparts. However, for sounds with a linear amplitude modulator, this perceptual asymmetry is partially accounted for by ramped tone over-estimation, contrasting previous findings in the literature conducted with exponential amplitude modulators.