High facial width-to-height ratio (fWHR) has been associated with a cluster of behavioural traits in men, including aggression and status-striving. This association between face structure and behaviour may be caused by testosterone.
There is convincing literature indicating a rise in testosterone levels following perceived success in a competitive situation (winning and in exposure to potential mates). Two consequences follow: firstly, men who exhibit a stronger hormonal reaction to positive outcomes of competitive or mating situations will be exposed to more testosterone compared to those men who have a lesser reaction. Secondly, irrespective of individual differences in hormone reactivity, those men that experience winning more competitive situations will have higher total exposure.