Differences in Facial Expressions between Spontaneous and Posed Smiles: Automated Method by Action Units and Three-Dimensional Facial Landmarks.

Seho Park,Jae-A Lim,Jeong-Shim Kim,Hakrim Kim,Eui Chul Lee,Taehoon Kim,Jun-Young Lee,Soowon Park,Hyunwoong Ko,Kunyoung Lee,Jung-In Lee,Seong-Jae Han

doi:10.3390/s20041199

Abstract

Research on emotion recognition from facial expressions has found evidence of different muscle movements between genuine and posed smiles. To further confirm discrete movement intensities of each facial segment, we explored differences in facial expressions between spontaneous and posed smiles with three-dimensional facial landmarks. Advanced machine analysis was adopted to measure changes in the dynamics of 68 segmented facial regions. A total of 57 normal adults (19 men, 38 women) who displayed adequate posed and spontaneous facial expressions for happiness were included in the analyses. The results indicate that spontaneous smiles have higher intensities for upper face than lower face. On the other hand, posed smiles showed higher intensities in the lower part of the face. Furthermore, the 3D facial landmark technique revealed that the left eyebrow displayed stronger intensity during spontaneous smiles than the right eyebrow. These findings suggest a potential application of landmark based emotion recognition that spontaneous smiles can be distinguished from posed smiles via measuring relative intensities between the upper and lower face with a focus on left-sided asymmetry in the upper region.

Highlights

IntroductionThe smile plays a pivotal role in the exchange of emotional states in non-verbal communication [1]
The smile plays a pivotal role in the exchange of emotional states in non-verbal communication [1].Generally recognized as an epitome of positive affect, research on facial expression of happiness has long been considered as a major focus of emotional expression
The results reported in the present study support the automated 3D facial landmark detection could effectively distinguish genuine smiles from posed smiles

Summary

Introduction

The smile plays a pivotal role in the exchange of emotional states in non-verbal communication [1]. Recognized as an epitome of positive affect, research on facial expression of happiness has long been considered as a major focus of emotional expression. The most obtrusive facial movements of a typical smile are known to engage the zygomatic major; a facial muscle on the cheek that is capable of pulling the corners of the mouth. Sensors 2020, 20, 1199 without positive feelings during communication. Fake smiles may appear to obscure one’s true emotional state. Previous research has distinguished Duchenne smile as opposed to a fake smile with additional movements around the eyes, the orbicularis oculi region [3]. The appearance of Duchenne markers has been widely adopted as genuine, spontaneous smiles while the absence indicated posed smiles. The appearance of Duchenne markers has been widely adopted as genuine, spontaneous smiles while the absence indicated posed smiles. [4,5]

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Discussion

Conclusion