Adaptive auditory brightness perception

Perception adapts to the properties of prior stimulation, as illustrated by phenomena such as visual color constancy or speech context effects. In the auditory domain, only little is known about adaptive processes when it comes to the attribute of auditory brightness. Here, we report an experiment that tests whether listeners adapt to spectral colorations imposed on naturalistic music and speech excerpts. Our results indicate consistent contrastive adaptation of auditory brightness judgments on a trial-by-trial basis. The pattern of results suggest that the strength of these effects tends to grow with an increase in the duration of the adaptor context, but levels off after around 8 trials of 2 s duration. A simple model of the response criterion yields a correlation of r=.97 with the measured data and corroborates the notion that brightness perception adapts on timescales that fall in the range of auditory short-term memory. Effects turn out to be similar for spectral manipulations based on linear spectral slopes and manipulations based on a measured transfer function from a commercially available hearing device. Overall, our findings demonstrate adaptation of auditory brightness perception under realistic acoustical conditions.