Whether performing a syllogistic reasoning task (SRT) affects emotional state in different prior moods was tested using eighty participants in either a positive, negative, or neutral mood. A film mood induction procedure (MZP) was used and affective state was assessed before the MIP, after the MIP and after the SRT. The affective reactivity hypothesis - that personality influences the magnitude of affective change to an MIP - was also tested by having participants fill out the Eysenck Personality Inventory. Participants in a positive, but not in a negative or neutral, prior mood moved more negative after the SRT. Participants' pattern of affective reactivity partly replicated previous research but contrary to prediction in the positive condition extraversion was inversely related to increases in positive (in the MIP) and negative (in the SRT) affect. These results suggest that, under some conditions, people may adaptively move to the mood-state that is most conducive to the type of cognitive task they must perform.

Key words: reasoning, emotion, extraversion, introversion, affective reactivity