Facial Width-to-Height Ratio Calculated via Direct Measurement and its Relation to Aggressive Behaviour
The human face plays a fundamental role in communication and social interactions. Whether faces reflect behavioural or personality traits has been widely debated. The facial width-to-height ratio has emerged as a popular measure in this context because testosterone is believed to promote increased bizygomatic width in males, leading to a higher ratio. Testosterone is thought to be related with aggressive behaviour, thus, many previous studies have focused on the relationship between the facial width-toheight ratio and aggressiveness. However, most studies have focused on small Western samples, often relying on measurements derived from two-dimensional photographs. In this study, we examined the relationship between the facial width-to-height ratio and self-reported aggressive behaviour by directly measuring the facial height and width to calculate the facial width-to-height ratio. Our sample consisted of 196 students (88 males and 108 females). We assessed aggression using the Buss-Perry Aggression Questionnaire, which contains various subdomains. Supporting some prior research, our results did not reveal significant sexual dimorphism in the facial width-to-height ratio, nor did it associate with self-reported aggressiveness in the expected direction. In females, the subdomain of verbal aggression negatively predicted the facial widthto-height ratio, but after controlling for BMI, the relationship became insignificant. We also found a correlation between the facial width-to-height ratio and body mass index, suggesting that the facial width-to-height ratio may reflect underlying body mass differences rather than distinct facial morphological variations. Thus, we recommend a cautious approach when examining the facial width-to-height ratio as a sexually dimorphic feature.
