A study has revealed that kissing helps people judge the quality of a potential mate through their taste, smell and fitness.
The study, which was done by Oxford University, found that kissing was a way of getting a partner to stick around, the BBC reported.
The online survey of 900 adults showed that men and women, who were more attractive or had more casual sex partners, were more selective in choosing mates, and valued kissing more highly.
Robin Dunbar, experimental psychology professor at the Oxford University, said that initial attraction such as facial, body and social cues play an equally important role in courtship stages, later followed by kissing in the deeper stages.
The study also showed that kissing plays an important role before sex in short relationships and at a range of different times in committed relationships.
According to the survey, women value kissing more highly in long-term relationships, as it increases feelings of affection and attachment among couples.
The study was published in the journal Archives of Sexual Behaviour.
