Why the Wide Face? Androgen Receptor Gene Polymorphism does not Predict Men’s Facial Width-to-Height Ratio

Recent research has linked men’s facial width-to-height ratio (fWHR) to perceptions of aggressiveness, dominance and untrustworthiness, as well aggressive and exploitative behavior, leading to speculation that a wide face may be an indicator of an intrasexually-competitive behavioral strategy. Not understood, however, are the physiological mechanisms that produce fWHR variance and explain the link between fWHR and behavior. Several researchers have suggested that fWHR variance may be related to the number of CAG repeats in the androgen receptor gene (CAGn) – a polymorphism that regulates sensitivity to androgens – either directly or through an interaction with testosterone concentrations. We tested this hypothesis, and found that CAGn did not predict fWHR variance, either directly or by moderating the effect of testosterone concentrations. Furthermore, we found that fWHR did not predict baseline testosterone or testosterone reactivity in our full sample, but did predict baseline testosterone among our white participants. We discuss these results in relation to previous research on fWHR and testosterone, and suggest new mechanisms that may explain fWHR variation.