Relative influences of affect and cognition on behavior: are feelings or beliefs more related to blood donation intentions?

This study tested the relative predictive power of affect and cognition on global attitude and behavioral intention within the tripartite model of attitude structure. Participants (N = 264) completed questionnaires that included an item regarding blood donation experience, five semantic differential items, four behavioral intention items, and one global attitude item. Participants were randomly assigned to either an affective or cognitive instruction set for the semantic differential items. As predicted, semantic differentials were more highly correlated with both global attitude and behavioral intention when completed under the affective instructions than under the cognitive instructions. In addition, donors' and non-donors' attitudes on the semantic differential scales were distinguished from one another only when they were elicited under the affective instruction set. Results provide support for the tripartite model of attitude structure. Future research should examine the relative importance of affect and cognition in less emotion-laden domains.