Do Subliminal Fearful Facial Expressions Capture Attention?

Abstract

In two experiments, we tested whether fearful facial expressions capture attention in an awareness-independent fashion. In Experiment 1, participants searched for a visible neutral face presented at one of two positions. Prior to the target, a backward-masked and, thus, invisible emotional (fearful/disgusted) or neutral face was presented as a cue, either at target position or away from the target position. If negative emotional faces capture attention in a stimulus-driven way, we would have expected a cueing effect: better performance where fearful or disgusted facial cues were presented at target position than away from the target. However, no evidence of capture of attention was found, neither in behavior (response times or error rates), nor in event-related lateralizations (N2pc). In Experiment 2, we went one step further and used fearful faces as visible targets, too. Thereby, we sought to boost awareness-independent capture of attention by fearful faces. However, still, we found no significant attention-capture effect. Our results show that fearful facial expressions do not capture attention in an awareness-independent way. Results are discussed in light of existing theories.

Keywords: ERP; attention; emotion; facial expression; subliminal.

Figure 1

Face stimuli used in Experiments 1 and 2 (Lundqvist et al., 1998; Khalid et al., 2017): neutral faces (top row), fearful faces (middle row), and disgusted faces (bottom row). Males are on the left, females on the right.

Figure 2

Exemplary trial sequence of Experiment 1. The target face (neutral face) is at the right side, the distractor (disgusted face) on the left. In the cueing display, the neutral face is on the right side, and the fearful face cue is at the left (distractor position in the target display, hence, an invalid trial). Stimuli are not drawn to scale.

Figure 3

(A) Event-related potentials (ERPs) in Experiment 1 after cue onset collapsed over experimental conditions. Activity contralateral to negative emotional face cues is represented by a solid line, ipsilateral by a dotted line. (B) Scalp topographies for left/right cue presentation and the difference (in μV) averaged over 190–240 ms after cue onset (N2pc).

Figure 4

Differences in contra- minus ipsilateral event-related potentials (ERPs) in Experiment 1 after cue onset, depending on Negative Emotion and Orientation of the cue.

Figure 5

Experiment 1: Mean validity effect (VE) in reaction times (RTs; invalid minus valid; blue bars) and accuracies (ACCs; valid minus invalid; green bars) depending on Cue Orientation (upright; inverted). Error bars represent 95% confidence intervals.

Figure 6

(A) Event-related potentials (ERPs) in Experiment 2 after cue onset collapsed over experimental conditions. Activity contralateral to the fearful emotional cue is represented by a solid line, ipsilateral by a dotted line. (B) Scalp topographies for left/right cue presentation and difference (in μV) averaged over 200–250 ms after cue onset (N2pc).

Figure 7

Differences in contra- minus ipsilateral event-related potentials (ERPs) in Experiment 2 after cue onset depending on cueing displays’ Distractor Emotion and Cue Orientation.

Figure 8

Experiment 2: Mean validity effect (VE) in reaction times (RTs; invalid minus valid; blue bars) and accuracies (ACCs; valid minus invalid; green bars) depending on Orientation (upright; inverted). Error bars represent 95% confidence intervals.