Detecting Genuine and Deliberate Displays of Surprise in Static and Dynamic Faces

Abstract

People are good at recognizing emotions from facial expressions, but less accurate at determining the authenticity of such expressions. We investigated whether this depends upon the technique that senders use to produce deliberate expressions, and on decoders seeing these in a dynamic or static format. Senders were filmed as they experienced genuine surprise in response to a jack-in-the-box (Genuine). Other senders faked surprise with no preparation (Improvised) or after having first experienced genuine surprise themselves (Rehearsed). Decoders rated the genuineness and intensity of these expressions, and the confidence of their judgment. It was found that both expression type and presentation format impacted decoder perception and accurate discrimination. Genuine surprise achieved the highest ratings of genuineness, intensity, and judgmental confidence (dynamic only), and was fairly accurately discriminated from deliberate surprise expressions. In line with our predictions, Rehearsed expressions were perceived as more genuine (in dynamic presentation), whereas Improvised were seen as more intense (in static presentation). However, both were poorly discriminated as not being genuine. In general, dynamic stimuli improved authenticity discrimination accuracy and perceptual differences between expressions. While decoders could perceive subtle differences between different expressions (especially from dynamic displays), they were not adept at detecting if these were genuine or deliberate. We argue that senders are capable of producing genuine-looking expressions of surprise, enough to fool others as to their veracity.

Keywords: accuracy; emotions; facial expressions; genuineness; intensity; posed.

FIGURE 1

Stimuli used in the study illustrating the three types of surprise expressions: (a) Genuine, (b) Rehearsed, and (c) Improvised.

FIGURE 2

Mean ratings for perceived genuineness of facial expressions (error bars ±1 SE). Positive values indicate that expressions were perceived as more genuine, while negative values indicate that they were perceived as more fake. The asterisks represent a significant difference at ^∗p < 0.005 and ^∗∗p < 0.001.

FIGURE 3

Mean accuracies in authenticity discrimination in the dynamic and static format split by expression type (error bars ±1 SE). The lines above the bars represents a main effect of Format. The brackets above the bars represent a significant difference between Expression type. The asterisks represent a significant difference at p < 0.001. The dotted line represents chance performance (33.3%).

FIGURE 4

Mean ratings for perceived intensity of facial expressions (error bars ±1 SE). The asterisks represent a significant difference at ^∗p < 0.01 and ^∗∗p < 0.001.

FIGURE 5

Confidence scores in the dynamic and static format split by expression type (error bars ±1 SE). The asterisks represent a significant difference at ^∗p < 0.01 and ^∗∗p ≤ 0.001.