While a kiss may just be a kiss for a man, for a woman it is an all-important means of gauging a prospective partner's compatibility. She uses it, the study suggests, to assess a "rich and complex exchange" of romantic and chemical clues that pass between partners as their lips touch.
A "good kiss" will help convince her that the partner is worth persevering with but a man who is judged to be a bad kisser is unlikely to find himself invited in for coffee.
In the longer term, the woman treats kissing as a means to induce bonding and assess whether her partner has remained faithful and interested.
For men the kiss is much less important. It might be a source of hormonal information but it's mostly seen as a preliminary to sex. A man tends to regard a good kiss as one in which he's allowed to use his tongue and is rewarded with moans of pleasure, the study found.
"The information conveyed by a kiss can have profound consequences for romantic relationships, and can even be a major factor in ending one," Gordon Gallup, of the University at Albany in the US, said.
"While many forces lead two people to connect romantically, the kiss - particularly the first one - can be a deal-breaker."
The study, published in the online journal Evolutionary Psychology, suggests that clues to a person's health are passed on by kissing. These clues are picked up and understood - consciously or unconsciously - by the kissers but are more important to the female because she is more interested in a long-term relationship.
Women were more likely than men to take into account the smell of their partner's breath, the taste of their mouth and the state of their teeth during a kiss.
Women were less than half as likely to have sex with a man without first enjoying a kiss, and less likely to tolerate tongues on a first date. Men were much more likely both to continue to want sex even with a bad kisser or without bothering with a kiss.
Once a relationship was established, the researchers found, men grew less interested in kissing whereas women continued to give kisses a high priority. They were more likely to kiss a partner after sex than men were.
Researchers from three US universities surveyed 1041 college students, most aged 18 to 25.