Focusing on Mouth Movement to Improve Genuine Smile Recognition

Abstract

Smiles are the most commonly and frequently used facial expressions by human beings. Some scholars claimed that the low accuracy in recognizing genuine smiles is explained by the perceptual-attentional hypothesis, meaning that observers either did not pay attention to responsible cues or were unable to recognize these cues (usually the Duchenne marker or AU6 displaying as contraction of muscles in eye regions). We investigated whether training (instructing participants to pay attention either to the Duchenne mark or to mouth movement) might help improve the recognition of genuine smiles, including accuracy and confidence. Results indicated that attention to mouth movement improves these people's ability to distinguish between genuine and posed smiles, with nullification of the alternative explanations such as sample distribution and intensity of lip pulling (AU12). The generalization of the conclusion requires further investigations. This study further argues that the perceptual-attentional hypothesis can explain smile genuineness recognition.

Keywords: Duchenne marker; dynamic lip; genuine and posed smiles; mouth movement; perceptual-attentional hypothesis; training.

FIGURE 1

Examples from the UvA-NEMO Smile Database (Dibeklioğlu et al., 2012) which was marked as publishable (but the permission is required to use the images), where (A) is a genuine smile and (B) a posed smile, illustrating the difficulty in distinguishing genuine smiles from static images.

FIGURE 2

Interaction between factor cue and session (1: pre-training; 2: post-training). The error bar indicates the 95% confidence interval.