IF YOU thought that kissing was all about love and romance and intimacy, well, forget it. It is actually all about biochemistry and neurotransmitters and evolution.
St Valentine’s Day notwithstanding, the reality behind philematology, the science of kissing to you and me, was laid bare yesterday at the American Association for the Advancement of Science’s annual meeting in Chicago.
The full rigours of science have been applied to the simple kiss shared between lovers and there is a lot more to it than you might think.
“It is a rather unusual behaviour,” suggested Prof Wendy Hill, provost and professor of neuroscience at Lafayette College in Pennsylvania, who pursued research to understand whether kissing had evolutionary “adaptive significance”.
Clearly it does given that more than 90 per cent of all human cultures engage in kissing of various sorts, offered Prof Helen Fisher of Rutgers University.
“You wouldn’t see that around the world and also in animals if it wasn’t important.”
She pointed out that chimps engage in kissing and many species have various forms of biting, nuzzling and other behaviours that seem to mimic what we do when kissing.
Elephants place their trunks in one another’s mouths and birds touch beaks, so it seems that many species are up for smooching.
Prof Hill decided to search for signs that kissing was selected during our evolution and devised an appropriate study. It involved bringing in 15 college couples and dividing them into two groups, one where they got to sit and hold hands and talk, and one where they got to have a good old snog. There were even flowers and music in the background to make people comfortable.
Prof Hill and her team collected saliva and blood samples both before the kissing – or hand-holding – got started and again immediately afterwards in an effort to measure levels of the bonding hormone oxytocin and the stress hormone cortisol.
Prof Fisher meanwhile conducted MRI scans which showed that huge swathes of the brain became active while kissing, more evidence if needed that there is something special about the kissing business.
Scans also showed that one part of the brain which was strongly active for those passionately in love also happened to be the brain centre involved in cocaine addiction and the satisfaction felt when eating chocolate.
The old song must be true, love is the drug.