Brain and Body

What's in a Kiss? A Lot More Than You Think

October 28, 2015 | Reece Alvarez

A young couple kissing under an umbrella
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Kissing is as natural as breathing for many, but why humans do it continues to be somewhat of a romantic mystery.

While kissing is a human behavior found across the globe, and even in our closest primate relatives like chimps and bonobos, the reason this common act is so profoundly linked to our social and romantic behaviors is still not entirely understood.

“There are three main theories about the role that kissing plays in sexual relationships: that it somehow helps assess the genetic quality of potential mates; that it is used to increase arousal (to initiate sex for example); and that it is useful in keeping relationships together,” said Rafael Wlodarski, the DPhil student who researched the motives behind kissing in the Department of Experimental Psychology at Oxford University. “We wanted to see which of these theories held up under closer scrutiny."

SEE ALSO: Girls Lose Friends for Having Sex, Boys Gain Them, Study Shows

To understand more, Rafael Wlodarski and Professor Robin Dunbar of Oxford University set up an online questionnaire in which over 900 adults answered questions about the importance of kissing in both short-term and long-term relationships.

In humans, as in all mammals, females must invest more time than men in having offspring — pregnancy takes nine months and breast-feeding may take up to several years. Previous studies have shown women tend to be more selective when initially choosing a partner. Men and women who are more attractive, or have more casual sex partners, have also been found to be more selective in choosing potential mates.  These groups tended to value kissing more in their survey responses, which suggests that smooching helps in assessing potential mates.

The survey responses showed that women rated kissing as generally more important in relationships than men, and it has been previously suggested that kissing may allow people to subconsciously assess a potential partner through taste or smell — picking up on biological cues for compatibility, genetic fitness or general health, the researchers said.

Beyond the first dates

Past research has also found that women place greater value on activities that strengthen long-term relationships (since raising offspring is made easier with two parents present). In their study, the team found that kissing's importance changed for people according to whether it was being done in long-term or short-term relationships. Particularly, it was rated by women as more important in long-term relationships, suggesting that locking lips also plays an important role in mediating affection and attachment among established couples.

While high levels of arousal might be a consequence of kissing (particularly as a prelude to sex), the researchers say it does not appear to be a driving factor that explains why we kiss in romantic relationships.

In short relationships, survey participants said kissing was most important before sex, less so during sex, less important again after sex and least important at other times. In committed relationships, where forming and maintaining a lasting bond is an important goal, kissing was equally important before sex and at times not related to sex.

More frequent kissing in a relationship was linked to the quality of a relationship, while this wasn't the case for having more sex. However, people's satisfaction with the amount of both kissing and sex did tally with the quality of their relationships.

Based on a press release from Spring Science+Business Media


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