Exposure is not enough: suppressing stimuli from awareness can abolish the mere exposure effect

Abstract

Passive exposure to neutral stimuli increases subsequent liking of those stimuli--the mere exposure effect. Because of the broad implications for understanding and controlling human preferences, the role of conscious awareness in mere exposure has received much attention. Previous studies have claimed that the mere exposure effect can occur without conscious awareness of the stimuli. In two experiments, we applied a technique new to the mere exposure literature, called continuous flash suppression, to expose stimuli for a controlled duration with and without awareness. To ensure the reliability of the awareness manipulation, awareness was monitored on a trial-by-trial basis. Our results show that under these conditions the mere exposure effect does not occur without conscious awareness. In contrast, only when participants were aware of the stimuli did exposure increase liking and recognition. Together these data are consistent with the idea that the mere exposure effect requires conscious awareness and has important implications for theories of memory and affect.

Figure 1. Stimuli, exposure procedure and results for suppressed and unsuppressed exposure conditions of Experiment 1.

(A) Contours were presented to the left eye while either visual noise patterns or visual noise patterns with a superimposed contour were rapidly flashed to the right eye. A contour (left eye) and visual noise patterns alone (right eye) resulted in the percept of only the visual noise patterns (suppressed). A contour (left eye) and visual noise patterns with a superimposed contour (right eye) resulted in the percept of the visual noise patterns and the contour (unsuppressed). (B) Mean ratings of pleasantness for stimuli given 0, 1, 10 or 20 suppressed or unsuppressed exposures. (C) Mean ratings of recognition for suppressed and unsuppressed stimuli as a function of exposure frequency. Error bars indicate standard error of the means (SEM).

Figure 2. Mean pleasantness (A) and recognition (B) for faces given 0, 1, 10 or 20 suppressed or unsuppressed exposures.

Error bars indicate ±SEM.