Science Questions

Is there an evolutionary advantage to kissing?

I would like to know if there is any evolutionary basis and any biological advantage why humans kiss. Nelson, East Africa

We put this question to Gordon Gallup, Professor of Psychology from the State University of New York at Albany...

Gordon -   We think that kissing is part of an evolved courtship strategy and that kissing conveys information at an unconscious level about health and a person’s reproductive viability.

We’ve discovered that among the majority of undergraduates that we’ve surveyed, they report (both males and females) having been attracted to someone, only to discover on one or more occasions that after they kissed them for the first time they were no longer interested.  So we think there are hardwired unconscious mechanisms that come into play at the moment of a kiss based on the exchange of information, based on posture, and odour, and taste, and smell that activate mechanisms that come into play to make a determination about whether continuation in this relationship would be in the person’s long term reproductive best interest. 

We discovered that females place a lot more emphasis on kissing than males do.  Females not only kiss for purposes of mate assessment, but once females are in committed relationships, they continue to rely on kissing as a means of monitoring and updating the status of their relationship.  Males on the other hand tend to kiss for one or two reasons.  Primarily as a means to an end. Namely for purposes of gaining sexual favours, or as a means of attempting to achieve reconciliation.

Diana -   A kiss might tell us something of our partner’s fertility and Gallup found that the majority of females used kissing to check on their relationship whilst males see it as a stage in getting to sex.  Though this likely isn’t true of everyone – Gallup also hypothesises that during a kiss between a male and female, some of the men’s testosterone may be transferred to the female.  Over a long period of time, this could affect her libido.

July 2010