TEMPORAL AND SPECTRAL PREDICTIONS COMPLEMENTARILY BENEFIT AUDITORY TARGET DETECTION

Auditory perception benefits from predictions about both when and what sounds will occur. Yet it remains unclear how these predictive dimensions jointly shape behaviour, particularly under non-rhythmic listening conditions. Here, we tested temporal and spectral predictability in a challenging, non-rhythmic auditory detection task. Temporal predictability primarily increased response readiness: participants responded faster and produced more hits, but also more false alarms. Spectral predictability, in contrast, selectively improved sensitivity, mainly by reducing false alarms, without a comparable speeding of response times. Beyond these main effects, sensitivity was further increased when both dimensions were predictive, indicating that temporal and spectral predictions interact to jointly optimise sensitivity, consistent with a spectrotemporal filtering account. Furthermore, we observed qualitatively different patterns of effects across temporal and spectral variability. Under temporal uncertainty, performance showed a non-monotonic dependence on foreperiod duration, with best performance at longer intermediate foreperiods. In contrast, performance across target frequencies showed no comparable optimisation and remained largely stable across the frequency distribution. Together, these findings show that under challenging listening conditions, temporal and spectral predictions provide complementary benefits to response readiness and perceptual sensitivity and are extracted in distinct ways from the statistical regularities of the auditory input.