Evaluation and Validation of Emotional Expression Mimicry Tasks for Highly Sensitive Person Assessment

Abstract

In recent years, Highly Sensitive Persons (HSP) have gained increasing attention. HSP refers to individuals with heightened sensory sensitivity, making them more sensitive to stimuli and frequently more empathetic. In this study, we focused on HSPs’ high empathy and their ability to detect subtle cues from facial expressions. We hypothesized that individuals with HSP tendencies are more likely to perceive and express minor changes in facial expressions. To test this hypothesis, we created deliberate facial expressions representing nine emotional states, i.e., happiness (four levels), neutrality (one level), and sadness (four levels). We measured mouth corner movements using the MediaPipe system, which is a webcam-based motion capture system. The subjects imitated 10 facial expressions, ranging from neutral to happy and sad, each with five levels of intensity. We then examined the correlations between the subjects’ facial expressions and psychological measures, including the Highly Sensitive Person Scale (HSPS) and the Japanese version of the Interpersonal Reactivity Index. The result exhibited correlations in specific intervals. First, there was a strong correlation in the five-level range from neutral to happy (r = 0.67). Second, there was a correlation in the interval from minor expression change from neutral to the second level of happiness (r = 0.50). Third, a correlation was observed in the interval from the second to the fourth level of happiness (r = 0.61). These results suggest that individuals with higher HSPS scores (indicating HSP tendencies) exhibit greater changes in facial expressions when experiencing happiness, which suggests that those with HSP tendencies are more receptive to subtle changes in intentional facial expression mimicking stimuli, particularly happiness.