From my upcoming book The Science of Kissing! Have questions? Message me and I’ll choose some to answer here…
All taken from Sheril Kirshenbaum’s book The Science Of Kissing which comes out January 2011. My elementary comments in bold.
1. Human lips are different from those of all other animals because they are everted, meaning that they purse outward.
2. But we are not the only species to engage in kissing-like behaviors. Great apes press their lips together to express excitement, affection, or reconciliation.
3. Being close enough to kiss helps our noses assess compatibility. In a landmark study in Switzerland it was reported that women prefer the scents of men whose immunity-coding genes are different from their own. Mixing genes that way may produce offspring with a stronger immune system.
4. Dopamine, a neurotransmitter associated with feelings of desire and reward, spikes in response to novel experiences, which explains why a kiss with someone new can feel so special. (“New love is tasteless” - ETID)
5. In some people, a jolt of dopamine can cause a loss of appetite and an inability to sleep, symptoms commonly associated with falling in love. (Oh, chemistry, stop controlling me!)
6. Dopamine is produced in the ventral tegmental area of the brain, the same region affected by addictive drugs like cocaine. (This explains a lot.)
7. In men, a passionate kiss can also promote the hormone oxytocin, which fosters bonding and attachment. (Damnit!)
8. The exchange of saliva could provide a reproductive advantage for males. During an open-mouthed kiss, a man passes a bit of testosterone to his partner. Over weeks, and months, repeated kissing could enhance a females libido, making her more receptive to sex.
9. Evolutionary-psychologists have discovered that men are far more likely to prefer sloppy tongue kisses than women. (We are nasty fools!)
10. One milliliter of saliva contains about a 100 million bacteria.