Geometric morphometric analysis of Japanese female facial shape in relation to psychological impression space

Facial appearance has essential consequences in various social interactions. Previous studies have shown that although people can perceive a variety of impressions from a face, these impressions may form from a relatively small number of core dimensions in the psychological impression space (e.g., valence and dominance). However, few studies have thus far examined which facial shape features contribute to perceptions of the core trait impression dimensions for Asian female faces. This study aimed to identify the commonalities between various facial impressions of Japanese female faces and determine the facial shape components associated with such impressions by applying geometric morphometric (GMM) analysis. In Experiment 1 (Modeling study), Japanese female faces were evaluated in terms of 18 trait adjectives that are frequently used to describe facial appearance in daily life. We found that Japanese female facial appearance is indeed evaluated mainly on the valence and dominance dimensions. In Experiment 2 (Validation study), we confirmed that all the trait impressions were quantitatively manipulated by transforming the facial shape features associated with valence and dominance. Our results provide evidence that various facial impressions derived from these two underlying dimensions can be quantitatively manipulated by transforming facial shape using the GMM techniques.