Individual alpha frequency predicts the sensitivity of time perception

Abstract

A growing body of research links individual differences in the frequency of alpha-band oscillations to temporal aspects of perception. However, whether the human alpha rhythm is a correlate of time perception itself has remained controversial. This study combined EEG with multiple duration estimation and discrimination tasks in order to evaluate whether individual alpha frequency (IAF) is associated with sensitivity or bias in judging visual durations across a range of peri-second durations (spanning 100 to 1200 ms). In a temporal estimation task, participants (n = 55) reported the duration of a single stimulus between 300–1200 ms. In a temporal discrimination task, participants reported which of two stimuli was longer: a standard (100, 600, or 1200 ms) or comparison (50–150% of the standard). Stimuli also varied in whether their luminance was static or dynamic (varying randomly over time). We found that IAF was significantly related to the variance of duration estimates, a measure of precision (or sensitivity), but not average duration estimates, a measure of bias. Further supporting this relationship, psychometric function slopes obtained from the independent duration discrimination tasks were positively correlated with IAF, particularly for the static stimulus conditions. These effects were largely consistent across the range of stimulus durations tested and held when controlling for participant age. Taken together, these results suggest that IAF may play a role in shaping individual differences in the sensitivity of time perception.