The role of affect in the mere exposure effect: Evidence from psychophysiological and individual differences approaches

Affective models of the mere exposure effect propose that repeated exposure to a stimulus increases the positive affect or reduces the negative affect toward the stimulus, whereas recent cognitive models propose that affect is not involved in the mere exposure effect. To test these competing predictions, participants repeatedly viewed photographs of women's faces and then viewed these women again (familiar) and novel women (unfamiliar) while facial muscle region activity and brain activity were recorded. Familiar stimuli were rated as more likable and they evoked more zygomatic (cheek) muscle region activity than unfamiliar stimuli. Interactions with individual differences occurred. Persons reporting less positive affect and persons reporting more negative affect at baseline evidenced more zygomatic activity to the familiar than to the unfamiliar. Persons with relatively less left frontal cortical activation at baseline evidenced a tendency toward a greater mere exposure effect. These results suggest that repeatedly exposing persons to nonreinforced stimuli increases their positive affective reactions to those stimuli.