Relationship of P3b single-trial latencies and response times in one, two, and three-stimulus oddball tasks.

•Participants completed one, two, and three-stimulus oddball tasks.•We used a novel technique called HSMM-MVPA to analyze EEG data from the tasks.•HSMM-MVPA revealed a processing stage corresponding to the P3b in each task.•P3b latency correlated with RTs only in the tasks requiring stimulus categorization.•The N1 appeared as a phasic trough of an ongoing alpha oscillation.