Investigating the role of temporal fine structure in everyday hearing

Abstract

Human listeners can derive substantial masking release when there are discrepancies in pitch or spatial location between the target and masking sounds. While the temporal fine-structure (TFS) in low-frequency sounds can convey information about both pitch and location, a nuanced debate exists in the literature about the role of these TFS cues in masking release. The long-term goal of the present study is to leverage individual differences to understand the role of TFS in everyday hearing. As a first step, we sought to measure individual TFS sensitivity using monaural frequency modulation (FM) and binaural interaural time difference (ITD) detection tasks. Preliminary data show large individual differences in these measures. Moreover, individual differences in ITD sensitivity were correlated with monaural FM sensitivity suggesting that monaural TFS coding can be a primary bottleneck determining binaural sensitivity. Alternately, both FM and ITD sensitivity variations could be reflecting common non-sensory factors (e.g., attention). To disambiguate between these hypotheses, we designed two passive EEG metrics of TFS coding. Follow-up experiments will compare individual differences in these perceptual and EEG measures to each other, and to speech-in-noise perception in complex environments.