Perceptual constancy for real‐room reverberation in loudness judgements and the effects of interstimulus interval.

Abstract

Narrowband stimuli shaped with fast‐onset and slow‐offset temporal envelopes are judged to be less loud than their reversed counterparts, particularly when preceded by a slow‐offset standard. It has been suggested that a “perceptual constancy” may be responsible for this “loudness context effect.” The idea is that when a slow‐offset “tail” is at the end of a sound it is largely attributed to listening‐environment reflections and is discounted in the listener’s loudness judgment. Previous experiments have shown that this effect is even bigger when real‐room reflection‐patterns are used. The present experiments varied the interval between the standard and comparison tones (ISI) to investigate the contribution of time‐order effects to these loudness judgements. Such effects might arise as the peak‐to‐peak interval between sounds changes with reversal of the standard, thereby confounding the duration of this interval with the presence of a “tail” in the standard. Results show that the loudness context effect reported earlier remains prominent across a range of ISI times and that the influence of any time‐order effects is relatively weak. Consequently, these findings remain consistent with the idea that the context effect arises through a perceptual constancy. [Work supported by EPSRC.]