What's in a kiss? A study by Oxford
University researchers suggests kissing helps us
size up potential partners and, once in a
relationship, may be a way of getting a partner
to stick around.
'Kissing in human sexual relationships is
incredibly prevalent in various forms across just
about every society and culture,' says Rafael
Wlodarski, the DPhil student who carried out
the research in the Department of Experimental
Psychology at Oxford University.
'Kissing is seen in our closest primate relatives,
chimps and bonobos, but it is much less intense
and less commonly used.
'So here's a human courtship behaviour which
is incredibly widespread and common and, in
extent, is quite unique. And we are still not
exactly sure why it is so widespread or what
purpose it serves.'
How the research was done
To understand more, Rafael Wlodarski and
Professor Robin Dunbar 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.
Rafael Wlodarski explains: '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. We wanted to see which
of these theories held up under closer scrutiny.'
The researchers report their findings in two
papers, one in the journal Archives of Sexual
Behavior and the second in the journal Human
Nature. They were funded by the European
Research Council.
The survey responses showed that women rated
kissing as generally more important in
relationships than men. Furthermore, men and
women who rated themselves as being
attractive, or who tended to have more short-
term relationships and casual encounters, also
rated kissing as being more important.
Women more selective
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. As it is these groups which tended to
value kissing more in their survey responses, it
suggests that kissing helps in assessing
potential mates.
It has been suggested previously 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.
'Mate choice and courtship in humans is
complex,' says Professor Robin Dunbar. 'It
involves a series of periods of assessments
where people ask themselves "shall I carry on
deeper into this relationship?" Initial attraction
may include facial, body and social cues. Then
assessments become more and more intimate
as we go deeper into the courtship stages, and
this is where kissing comes in.'
He adds: 'In choosing partners, we have to deal
with the "Jane Austen problem": How long do
you wait for Mr Darcy to come along when you
can't wait forever and there may be lots of you
waiting just for him? At what point do you have
to compromise for the curate?
'What Jane Austen realised is that people are
extremely good at assessing where they are in
the "mating market" and pitch their demands
accordingly. It depends what kind of poker hand
you've been dealt. If you have a strong bidding
hand, you can afford to be much more
demanding and choosy when it comes to
prospective mates.
'We see some of that coming out in the results
of our survey, suggesting that kissing plays a
role in assessing a potential partner,' Professor
Dunbar explains.
The importance of kissing
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 the current 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 kissing
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.
Other findings included:
* In short relationships, survey participants said
kissing was most important before sex, less so
during sex, was less important again after sex
and was least important at other times. In
committed relationships, where forming and
maintain 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 that
relationship.
* In a companion paper in the journal Human
Nature, the researchers report that women's
attitudes to romantic kissing also depend on
where in their menstrual cycle and their
relationship they are. Women valued kissing
most at initial stages of a relationship when
they were in the part of their cycle when they
are most likely to conceive. Previous studies
have shown that hormonal changes associated
with the menstrual cycle can change a woman's
preferences for a potential mate. When chances
of conceiving are highest, women seem to prefer
men who display supposed signals of
underlying genetic fitness, such as masculinised
faces, facial symmetry, social dominance, and
genetic compatibility. It appears that kissing a
romantic potential partner at this time helps
women assess the genetic quality of a potential
mate, the researchers say.
