There is a growing interest in investigating the role of affective and cognitive bases of attitude on intention and subsequent behavior, within a Theory of Planned behavior (TPB) framework. This research attempts to investigate the relative effects of cognitive versus affective attitudes on physical activity (PA), in two related studies. Thirty-five undergraduate students took part in the first study in which we assessed the classic TPB components, together with cognitive and affective attitudes. The second study, designed as a randomized controlled trial (RCT) employed an intervention using either cognitive persuasion messages (N=21), affective messages (N=21) or no messages (N=20), delivered via leaflets to a sample of students. The results of first study show that affective attitudes significantly predict intention to exercise while the other variables have no effect. Also, people with higher levels of PA held more positive affective attitudes towards exercise than sedentary ones, while for cognitive attitudes or other TPB variables no such differences occurred. For the second study, results show that the affective persuasion messages had an effect on intention and affective attitudes immediately after the intervention, but effects were no longer evident two weeks after the intervention delivery. Neither of the interventions had any effects on exercise. Although no effect of interventions was observed, there is enough evidence from both studies to infer that affective attitudes might hold a central role in the prediction of intention and subsequent behavior and further studies should unraveled mechanism by which these attitudes influence behavior.
KEYWORDS: affective attitudes, cognitive attitudes, exercise, intervention