Men weigh up potential partners almost instantaneously based on their appearance because their "ancient" genetic¹ preference for attractive mates leads them to, experts claim.

据专家介绍，男性在择偶时之所以会以貌取人，是因为他们天生爱美女的“原始基因”使然。

Men who instantly judge a woman based on her looks are simply following their survival instincts, scientists say.

According to research, a woman with an attractive face is taken by men to be fertile and able to continue the family line, appealing to（对……有吸引力） the man's survival instinct（本能，天性） .

In contrast women take longer to decide their feelings for a man because they need to weigh up whether he will be a committed partner who will provide for them well – part of their survival programming.

Professor Mark van Vugt and Dr Johanna van Hooff, from the University of Amsterdam, and postgraduate² student Helen Crawford, from the University of Kent, were behind the study which is to be published by the Oxford³ Journal Social Cognitive⁴ and Affective Neuroscience.

They tested men and women's bias⁵（偏见，偏袒） towards looks by conducting a series of tests on 20 women and 20 men, making them perform tasks while recording⁶ their brain activity.

While the subjects were doing the task they were shown a series of photographs of faces of the opposite sex, ranging from attractive to ugly.

Men were easily distracted when they saw a pretty face but women stuck to the task.

Prof van Vugt said: "Men definitely have the most wandering（漫游的） eye but it is because they have evolved to pay attention to cues of fertility and one of those cues is facial beauty – it's not that men are shallow.

"But we found they do make snap（突然的） judgments⁷ about women, much earlier than was previously⁸ thought. They make that decision on whether a woman would be a good mating partner in milliseconds.

"This is something very ancient and a way of helping⁹ men find the best mate to produce children.

"Women were not distracted by attractive male faces because women need more proof of whether a man is a good mate.

"Women make that decision on behaviour, whether a man is trustworthy（可信赖的，可靠的） and committed. They make their decision much later than men."