ERP prediction error responses under temporal constraints

Abstract

Anticipating future events is fundamental to adaptive behaviour. This study used EEG to examine how the brain processes multiple concurrent predictions under time constraints. On each trial, participants heard two auditory cues predicting different features (tilt and spatial frequency) of an upcoming visual stimulus (a Gabor patch), with cues presented either 200 ms or 1000 ms apart. The visual stimulus could either match both predicted features, violate both, or match only one while violating the other. We analysed event-related potentials (ERPs) to the Gabor patch to assess prediction error (PE) responses. Violations of the first cue’s prediction consistently elicited robust N2b responses, even when the second cue’s prediction was accurate. Violations of both cues produced similarly strong N2b amplitudes, while isolated violations of the second cue had no significant effect. No differences emerged between short and long cue intervals, suggesting that the temporal gap did not modulate PE processing. These results point to a bottleneck in integrating sequential predictions, with earlier cues dominating PE-related EEG responses under temporal constraints.