Abstract
Previous studies have found that individuals rate category members as more typical of their categories in a positive rather than negative mood, but the explanation for this effect remains unclear. In this thesis, four existing accounts were considered: The affective priming account, the mood as information account, the cognitive restructuring account, and the affect misattribution account. In all studies, participants were trained to recognize mathematically distorted dot patterns of two uncommon geometric shapes before judging the typicality of distortions. Studies 1, 2, and 3 attempted to test the affective priming account, an account that relies on positive mood priming emotional dimensions of stimuli, by using dot patterns which lack these emotional dimensions. In Study 1, which induced mood by presenting affective primes briefly before each stimulus, there was no difference in ratings between stimuli preceded by a positive or negative prime, as predicted by the affective priming account. However, Study 2 and 3, which induced mood before the stimulus rating phase by a combination of mood suggestive music and autobiographical recall, revealed consistent (but weak) evidence against the affective priming account. Finally, Study 4, a replication of Study 2 with an added attribution condition, tested the remaining theories. The results showed that there was a main effect of mood, regardless of how mood was attributed, offering evidence against the affect misattribution and mood-as-information accounts. These accounts state that attributing mood should result in no difference between mood conditions. This finding also offered further evidence against the affective priming account. Therefore, by attrition, the cognitive restructuring account offered the soundest explanation for mood-driven category inclusiveness in the current studies.