2012 年 31 巻 1 号 p. 75-76
The subliminal mere exposure effect is a psychological phenomenon where people tend to prefer stimuli that they have been subliminally exposed to even if they cannot recognize the observed stimuli. One explanation for this effect is that the resulting perceptual fluency is misattributed to a feeling of preference. Thus, an increased perceptual fluency should correspond to decreased invested mental effort. Because the pupil constricts as mental effort decreases, we predict that if perceptual fluency does induce a preference for the exposed stimulus, then participants showing pupil constriction during subliminal exposure will exhibit the mere exposure effect later. To examine our hypothesis, we measured the pupil diameter while participants were visually exposed to subliminal stimuli. After exposure, participants judged their preferences to the stimuli. We found that pupil diameter during subliminal exposure was significantly smaller for participants who later exhibited the mere exposure effect, suggesting that perceptual fluency may be the underlying mechanism of the subliminal mere exposure effect.