The Effects of Attitude, Subjective Norm, and Perceived Behavioral Control on Consumers’ Purchase Intentions: The Moderating Effects of Product Knowledge and Attention to Social Comparison Information

The purpose of this research is to investigate whether the relative influences of attitude, subjective norm, and perceived behavioral control on consumers’ purchase intentions will be different when consumers possess different levels of product knowledge (subjective and objective) and attention to social comparison information (ATSCI). As proposed by the theory of planned behavior, consumers’ purchase intentions are affected not only by their attitudes, but also by their group’s influences and their own perceived control. The relative strength of effects of these three factors on consumers’ purchase intentions is expected to vary across behaviors and situations. The results showed that the relative importance of attitude, subjective norm, and perceived behavioral control in the prediction of intention varies when consumers possess different levels of subjective product knowledge and ATSCI. Subjective knowledge is a moderating variable for the relationship between perceived behavioral control and purchase intention, while ATSCI was a moderating variable for the relationship between attitude and purchase intentions, and for the relationship between subjective norm and purchase intention. This research has strong implications for marketers. It can help them develop more effective marketing programs to affect consumers’ purchase intentions. In addition, the study is one of a few studies that applies the theory of planned behavior in the marketing field.