• Event-related potentials;
  • P3;
  • P4;
  • Slow wave;
  • Emotion;
  • Utility;
  • Learning


Event-related potentials (ERPs) were recorded to both predictive (consonant-vowel-consonant) and feedback (picture) stimuli as subjects learned associations between these stimuli. The consonantvowel-consonants (CVCs) were selected for lack of emotional content while the pictures (PICs) varied in emotional value (Learning Group; N=20). A second group of subjects was exposed to the same CVC-PIC stimuli but was required only to count the number of different CVCs and PICs (Counting Group; N=20). A principal components analysis with varimax rotation was performed on ERPs to PICs and revealed multiple late positive components (P3 and P4) and a slow positive wave (SPW). In both groups, the P3 and P4 factors varied with the emotional value of the stimuli. The learning group had a larger SPW than the counting group, and disconfirmed predictions elicited larger P4s than confirmed predictions. For CVC stimuli, only P4 increased as subjects learned CVC-PIC relationships. From the similar scalp and temporal distributions of P3 and P4, as well as their functional similarity, it was concluded that these two factors reflect the same neural process which is activated by the emotional value of stimuli. One possible function of this process is suggested.