Petty and Cacioppo (1980) have also studied physical attractiveness and involvement, although they manipulated argument strength rather than likability as the third factor. They, too, found a main effect for attractiveness and no attractiveness X involvement interaction. They had hypothesized that attractiveness was a peripheral cue for shampoo, the topic of their study, but they concluded, "in retrospect, it may have been that how the models looked was viewed as a relevant persuasive argument for some subjects" (p. 78).