The representational momentum effect and the reference dependence effect on the evaluation of dynamic happy expressions
Abstract: The majority of current research on facial expression perception uses static face images, and there is comparatively little study on dynamic expression. However, facial expressions are highly dynamic phenomena capable of conveying complex psychological states: the motion inherent in dynamic stimuli is crucial for social perception and improves coherence in identifying facial affect. Previous studies have found that perceptual processing of dynamic expressions may involve a variety of mechanisms, and some of these mechanisms have inconsistent effects. Therefore, it is important to study dynamic expressions to understand the nuances of human communication and support the naturalistic assessment of affective disorders.Three experiments involved 96 participants, which provided 94 valid samples. The experimental material came from the Chinese Affective Picture System (CASP). Dynamic expression sequences were created from the happy and neutral expressions of the same individual. In Experiment 1, the impact of direction change and the average summary representation were examined. Experiments 2a and 2b combined static expressions to systematically explored the representational momentum effect of dynamic happy expressions. As such, the average summary representation of dynamic expressions differed across the two experiments. Participants were asked to evaluate the valence, arousal, and dominance of the final emotion of dynamic expressions or static expressions on a seven-point scale. ANOVA, independent sample t-test, and one sample t-test were used to analyze the results.In this study, it was found that when the faces changed from strong to weak (versus weak to strong), they were rated with lower valence scores and higher dominance scores. In addition, faces that went from strong to weak had lower valence scores and higher dominance scores than static faces with the same intensity of expression in the previous frame. Indicative of the the representational momentum effect, faces that went from weak to strong had higher valence scores. Furthermore, the dynamic happy expressions that moved from strong to weak had a larger impact on perceived representational momentum than the dynamic happy expressions that moved from weak to strong. The arousal ratings were higher for the dynamic happy expression with a higher average summary representation. Valence, arousal, and dominance scores for the same expression image differed across experimental designs and material groups, according to this study's thorough analysis of repeated stimulus conditions (such as static 50% smiling).According to the results, representation momentum impact extends to the assessment of dynamic happy expression on valence and dominance dimensions. Additionally, when assessing a facial expression, the perceiver will make a relative assessment based on the internal reference standard: a lower the standard is associated with a higher the score, and vice versa. This finding is consistent with reference dependence effect on expression perception. These processing characteristics are used as a reminder to academics to consider the difference between dynamic and static expressions and to think about the impact of various materials when using facial expression data in the future.