Why do we kiss? It's complicated
THERE are some activities common to most people that we enjoy immensely, without much thought and as frequently as opportunity and instinct provide. On occasion, researchers feel the need to know why.
Recently, experimental psychologists at Oxford University explored the function of kissing in romantic relationships.
And surprise! It's complicated.
After conducting an online survey with 308 men and 594 women - mostly from North America and Europe - who ranged from 18 to 63 years old, the researchers concluded that kissing may help people assess potential mates and maintain those relationships.
"The repurposing of the behaviour is very efficient," said Mr Rafael Wlodarski, a doctoral candidate and lead author of the study, published in Archives Of Sexual Behavior.
But another hypothesis about kissing - to elevate sexual arousal and ready a couple for coitus - didn't hold up. While that might be an outcome, the researchers did not find sexual arousal to be the primary driver for kissing.
Participants in the survey were asked about their attitudes towards kissing in different phases of romantic relationships.
They were asked about their sexual history: For example, whether they had been more inclined towards casual encounters or long-term relationships. They also had to define their "mate value" by assessing their own attractiveness. Later, during data analysis, the researchers looked at how individual differences affected a person's thoughts on kissing.
The researchers defined kissing as on the lips or open-mouth.
Earlier research had suggested that in a new relationship, a romantic kiss serves to pull two strangers into each other's space, their faces glued together, possibly transmitting pheromonal, sensory and even genetic cues to each other's brain. This could be a kind of primal interview: Could this person be mating material?
Mr Wlodarski's results suggest a more nuanced dynamic.
The participants generally rated kissing in casual relationships as most important before sex, less important during sex, even less important after sex and least important "at other times".
Past research has shown that three types of people tend to be choosier in selecting mates who are genetically fit and compatible: Women, people who rate themselves highly attractive and people who favour casual sex.
In the study, those people said kissing was important mostly at the start of a relationship. That may be because, for them, kissing is a quick and easy way to sample a partner's suitability.
After that first kiss, those people are more likely than other subjects to change their mind about a potential partner. If it's not in his kiss, forget about him.
But other people - like men, those who rate themselves as less sexually attractive, and people looking for commitment - might use different criteria to size up their mates. In the search for a partner, these individuals screen for people who seem to have the inclination and resources for a long-term relationship. For them, kissing has a lower priority at the start of dating.
Particularly for men and women looking for long-term relationships, kissing serves other purposes, like relationship upkeep. It is about mediating, ameliorating and sustaining their connections. They rated kissing equally important before sex and at "other times not related to sex".
Among the study's participants who said they were in exclusive relationships, frequency of kissing, rather than of sexual intercourse, was best correlated with relationship happiness. For contented couples, kissing continued to be a conveyor of emotion.