Men with wider faces are more generous.

Here is an interesting piece from Stirrat and Perrett:

Male facial width-to-height ratio appears to correlate with antisocial tendencies, such as aggression, exploitation, cheating, and deception. We present evidence that male facial width-to-height ratio is also associated with a stereotypically male prosocial tendency: to increase cooperation with other in-group members during intergroup competition. We found that men who had wider faces, compared with men who had narrower faces, showed more self-sacrificing cooperation to help their group members when there was competition with another group. We propose that this finding makes sense given the evolutionary functions of social helpfulness and aggression.

Here are some rambling clips from their discussion:

Human cooperation and altruism have very likely evolved within a long history of conflict between group. Therefore, one would expect people to have evolved either innate responses or innate learning abilities regarding aggression between groups. There are good evolutionary reasons for men to be especially intergroup oriented, because membership in groups (like social status within those groups) correlates positively with the number of mating opportunities for men. As men with wider faces are rated as physically less attractive and display more antisocial behavior that is likely to be unattractive as well, males with wider faces may adopt this stereotypically male strategy of intergroup orientation and within-group helping behavior (including aggressive defense) as a compensatory strategy for affirming their group membership and gaining prestige with both men and women in their group.

Understanding this contingent inter- and intragroup male behavior is crucial to interpreting the relation between appearance and behavior. For example, in a fascinating recent article, Wong, Ormiston, and Haselhuhn indicated that the facial width-to-height ratio of chief executive officers (CEOs) predicted their firms’ financial performance. For Wong et al., the possible salient personal characteristics of the CEO that improve a firm’s performance are power and aggressive and exploitative behavior. Clearly, given the data in our study, it is possible that the correlation between CEOs’ facial width-to-height ratio and their firms’ financial performance is due not to CEOs’ aggressive tendencies, but to their tendencies toward self-sacrifice on behalf of their firms.