Unconscious processing of facial attractiveness: invisible attractive faces orient visual attention

Abstract

Past research has proven human's extraordinary ability to extract information from a face in the blink of an eye, including its emotion, gaze direction, and attractiveness. However, it remains elusive whether facial attractiveness can be processed and influences our behaviors in the complete absence of conscious awareness. Here we demonstrate unconscious processing of facial attractiveness with three distinct approaches. In Experiment 1, the time taken for faces to break interocular suppression was measured. The results showed that attractive faces enjoyed the privilege of breaking suppression and reaching consciousness earlier. In Experiment 2, we further showed that attractive faces had lower visibility thresholds, again suggesting that facial attractiveness could be processed more easily to reach consciousness. Crucially, in Experiment 3, a significant decrease of accuracy on an orientation discrimination task subsequent to an invisible attractive face showed that attractive faces, albeit suppressed and invisible, still exerted an effect by orienting attention. Taken together, for the first time, we show that facial attractiveness can be processed in the complete absence of consciousness, and an unconscious attractive face is still capable of directing our attention.

Figure 1. Procedure and stimuli in Experiments 1 (top), 2 (middle), & 3 (bottom).

Colorful Mondrians were always presented on the dominant eye to ensure strong suppressive strength in all experiments. In Experiment 1, alpha of target increased from 0–75% over 10 seconds, either on the left or right of the fixation point. Participants were required to press a button when targets became visible (Detection task), and then answered the validity question (Location task). Time-to-detection (i.e. suppression time) was the dependent variable. In Experiment 2, alpha of target ramped up to designate value in one second. Participants were required to press a button when targets became visible (Detection task). Target face contrast was changed adaptively according to the response (detected/non-detected) throughout the experiment with a 1-up-1-down procedure. Contrast-to-detection (i.e. visibility threshold) was the dependent variable. In Experiment 3, an attractive face and an unattractive face were presented simultaneously on the left and right, followed by a brief flash (i.e. 100 ms) of a Gabor patch on the left or right. Participants were instructed to report the tilt of the Gabor patch and the visibility of the faces. Gabor orientation discrimination accuracy was compared subsequent to invisible attractive and unattractive faces.

Figure 2. Individual suppression time in Experiment 1.

Each column denotes one participant, ranked by strength of the effect. Dots denote suppression time of the attractive (red) and unattractive (blue) conditions (left y-axis). Error bars are SEM. Bars in the lower part of the figure show suppression time difference (right y-axis).

Figure 3

Visibility thresholds (i.e. contrasts) in percentage in Experiment 2. The left panel shows the visibility thresholds in the attractive (red) and unattractive (blue) conditions of individual participants, ranked by strength of the effect. The right panel shows the group mean.

Figure 4. Accuracies on the subsequent orientation discrimination task in Experiment 3.

The left panel shows the accuracies subsequent to an attractive (red) or an unattractive (blue) face of individual participants, ranked by strength of the effect. The right panel shows the group mean.