Sub-optimal construction of an auditory profile from temporally distributed spectral information.

Abstract

When spectral components of a complex sound are presented not simultaneously but distributed over time, human listeners can still, to a degree, perceptually recover the spectral profile of the sound. This capability of integrating spectral information over time was investigated using a cued informational masking paradigm. Listeners detected a 1-kHz pure tone in a simultaneous masker composed of six random-frequency tones drawn on every trial. The spectral profile of the masker was cued using a precursor sound that consisted of a sequence of 50-ms bursts, separated by inter-burst intervals of 100 ms. Each burst in the precursor consisted of pure tones at the masker frequencies with tones appearing at each of the masker frequencies at different presentation probabilities. As the presentation probability increased in different conditions, the detectability of the target improved, indicating reliable precursor cuing regarding the spectral content of the masker. For many listeners, performance did not significantly improve as the number of precursor bursts increased from 2 to 16, indicating inefficient integration of information beyond 2 bursts. Additional analyses suggest that when intensity of the bursts is relatively constant, the contribution of the precursor is dominated by information in the initial burst.