Neural correlates of perceptual biases in duration perception

How we perceive a current event depends not only on its immediate context, but also on how our internal expectations are shaped by prior experience. In time perception, these expectations manifest as systematic biases, namely sequential dependence, where the current percept is influenced by the previous stimulus, and central tendency, the overestimation of short durations and underestimation of long ones. Both perceptual biases, corresponding to individual beliefs about stimulus generation, can vary substantially between participants. However, the neural responses related to inter-individual differences in these biases remain poorly understood. Here, we investigate this question in a duration reproduction task. Our EEG results show that in the frontocentral region, the Contingent Negative Variation (CNV) while experiencing the current stimulus depends on the previous stimulus regardless of sequential dependence. In contrast, in the right parietal region, the slow potential was not influenced by previous duration but associated with inter-individual differences in sequential dependence. Stimulus-offset evoked P2 amplitude was associated with both central tendency and sequential dependence and P2 amplitude varied with previous stimulus duration depending on individual sequential dependence. A Bayesian model of time perception reproduced the observed neural dynamics of the frontocentral CNV and its dependence on previous stimulus duration, suggesting that individual internal time estimates and expectations of stimulus offset are reflected in EEG responses. Our results demonstrate that both forms of perceptual bias are reflected in neural activity while experiencing the ongoing stimulus, suggesting that neural processes related to perceptual biases directly affect the measurement of time.