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Behind Kissing

February 14, 2009

The evolutionary roots of kissing are a bit less romantic than you might think.

Transcript

BOB HIRSHON (host):
Why we kiss….I’m Bob Hirshon and this is Science Update.

If you think about it, kissing is a very odd thing to do. Yet it’s almost universal. Neuroscientist Wendy Hill of Lafayette College wondered why people began doing it. She says it’s likely that kissing evolved in the great apes from a primitive behavior called pre-mastication. This romantic act involves chewing up food and then transferring it to one’s baby through mouth-to-mouth contact.

WENDY HILL (Lafayette College):
And it in many ways resembles a French kiss, in terms of the oral stimulation saliva being transferred and so forth.

HIRSHON:
She says kissing probably evolved from this behavior because it helped strengthen pair bonds.

WENDY HILL:
Those pairs that engage in kissing would have a higher reproductive success as a result of that pair bond.

HIRSHON:
Kissing not only releases the love hormone oxytocin, it also helps reduce stress by moderating levels of the hormone cortisol. I’m Bob Hirshon, for AAAS, the science society.