EMOTIONAL EXPECTANCY - BRAIN ELECTRICAL-ACTIVITY ASSOCIATED WITH AN EMOTIONAL BIAS IN INTERPRETING LIFE EVENTS

University students in either an optimistic or pessimistic mood state read brief stories of daily life events as event-related brain potenti als were collected during the final word of each story. For subjects i n a pessimistic mood, a bias to expect negative outcomes was seen as a n N400/P300 effect over posterior scalp regions. For subjects in an op timistic mood, a differentiation between good and bad outcomes was als o observed, but it was specific to medial frontal areas. Analysis of s ingle-trial P300 latencies suggested that semantically incongruent and mood-incongruent outcome words resulted in increased median latency o f the late positive complex (LPC) and resulted in increased variabilit y of LPC latency across trials.