P300 and Stimulus Categorization: Two Plus One is not so Different from One Plus One

Abstract

ABSTRACT Event related brain potentials (ERPs) were recorded from subjects who were instructed to count one of three, equally probable tones presented in a random sequence. In another condition, the subjects had to count one of two stimuli, one of which was presented with a probability of .33. The data support the view that the pattern of variation of P300 amplitude with the sequential structure of the series depends on the category to which events are assigned, rather than on the individual stimuli eliciting the P300. Furthermore, the data support the idea that the amplitude of P300 elicited by task‐relevant stimuli is determined by the subjective probability associated with the eliciting event. DESCRIPTIONS: ERP, P300, Subjective probability, Stimulus categorization.