Individual Differences Reveal the Utility of Temporal Fine-Structure Processing for Speech Perception in Noise

The auditory system is unique among sensory systems in its ability to phase lock to and precisely follow very fast cycle-by-cycle fluctuations in the phase of sound-driven cochlear vibrations. Yet, the perceptual role of this temporal fine structure (TFS) code is debated. This fundamental gap is attributable to our inability to experimentally manipulate TFS cues without altering other perceptually relevant cues. Here, we circumnavigated this limitation by leveraging individual differences across 200 participants to systematically compare variations in TFS sensitivity to performance in a range of speech perception tasks. Results suggest that robust TFS sensitivity does not confer additional masking release from pitch or spatial cues, but appears to confer resilience against the effects of reverberation. Yet, across conditions, we also found that greater TFS sensitivity is associated with faster response times, consistent with reduced listening effort. These findings highlight the perceptual significance of TFS coding for everyday hearing.