We all like a lookalike

It is often said that opposites attract. But while this may be the case with lovers, when it comes to friends we prefer people just like us.

Scientists have found that we tend to rate as more attractive people of the same sex who have similar features to our own.

They say we are better disposed and more inclined to trust them - which may explain why we often form friendships with people who look or dress like ourselves.

But we have no instinctive fondness for someone of the opposite sex who has features like our own.

The researchers say this is an instinct that may have evolved to prevent too much inbreeding.

The findings could help to explain some famous alliances.

Actresses Nicole Kidman and Naomi Watts, who are strikingly similar, are the best of friends. Cameron Diaz and Drew Barrymore were inseparable during the filming of Charlie's Angels, while Ben Affleck and Matt Damon, who share dark good looks and a strong jawline, have a firm friendship.

The study, involving 53 men and 55 women, was conducted by psychologists at McMaster University in Canada. Volunteers were asked to rate a series of pictures of men and women for attractiveness.

Unknown to them, there were only two real photographs - one of a man, one of a woman.

The rest of the images were made by morphing each of these faces with pictures of the volunteers. None of the students guessed that some of the images contained elements of their own faces, according to a report in the Royal Society's journal of biological sciences Proceedings B.

When it came to rating people of their own sex for attractiveness, the volunteers tended to prefer the face that resembled their own.

But with opposite-sex faces, they showed no such preferences.

The lead author, Lisa DeBruine, said: 'Judging the attractiveness of people of the opposite sex may include how sexually desirable we find them. Judgments of people of the same sex are more likely to be made in terms of our overall regard for them.'