In Nature (also in the BBC), researchers find that pretty women distract heterosexual men.
It seems that the more macho a man is — at least according to his hormones — the more the sight of an attractive woman will affect his judgement.
Researchers at the University of Leuven in Belgium asked men to play an ultimatum game, in which they split a certain amount of money between them. High-testosterone men drove the hardest bargain — unless they had previously viewed pictures of bikini-clad models, in which case they were more likely to accept a poorer deal.
The sight of flesh had less effect on the bargaining tactics of low-testosterone men.
The testosterone dose that interested the researchers was that encountered by their participants when developing in the womb. This can be measured by comparing the lengths of the index and ring fingers — a relatively long ring finger is a sign of a high-testosterone man.