Often, in the middle of a party, you may have spotted an attractive girl/boy and said "She/He likes me? No, it can't be..." And this way you go home once again still lonesome...

But Sarah Hill, a psychologist at the University of Texas, Austin, pointed that people of both sexes regard the sexual competition as stronger than it really is. In fact, this low sexual esteem makes people put more energy in luring or keeping a mate. In her study, Dr Hill presented to heterosexual men and women photographs of different foreign people.

The subjects marked the attractiveness of those of their own sex as it would be for those of the opposite sex, and of those of the opposite sex for them. The researcher found that men regarded the other men as being more attractive to women than in reality, and women felt the same of the women. This was foreseeable: people tend to make the least costly error.

In men psychology, innocent friendliness is interpreted by men usually as a sign that women are sexually interested in them. That's why men face two wrong alternatives before approaching a woman: they can misunderstand that she is not interested, and they may not even bother trying to approach her for sex; or, when she is not interested, they can mistakenly intent and be rejected. This is a cheap price: some hurt feelings for a while, sometimes not even this.

Anyway, not trying at all cuts any opportunity to sex, and - in biological terms - it cuts the possibility to spread one's DNA. But for women, this could come with a much heavier price. They usually do not underestimate a man's interest in having sex but in a committed relationship.

Because when a woman errs, she might find herself growing a child alone. But no matter the motivation, the final result is the same for men and women. In the end, the one who gambles will win the game.