1. About two-thirds of all humans, male and female, tilt their heads to the right when kissing. It does not matter whether they are left- or right-handed.

2. Men think that kissing is a highly effective way to end a fight. Women think that’s hooey. For once, the women are incorrect. “The evidence shows,” says evolutionary psychology professor Gordon Gallup, that “kissing is so powerful for females that even though they deny it, once it occurs, they’re so affected by a kiss …” That they’re helpless in its grip? “Yup.”

3. Remember those great standing kisses in old movies, where the girl demonstrates ecstasy by lifting her delicately shod tootsie behind her? That move was called “foot pop.” Such as, “What we need here is more foot pop.”

4. The science of kissing is known as philematology. In use: “He spent his undergraduate years studying philematology.”

5. More men than women describe a good kiss as one that involves tongue contact, saliva exchange and moaning.

6. After a relationship is established, women are much more likely than men to use kissing to monitor the commitment. “There is good evidence that the frequency of kissing is a pretty good barometer of the status of a relationship,” Gallup says.

7. Kissing, of course, is not all moonlight and roses. It is implicated in the spread of mononucleosis and oral herpes. The connection to meningitis and gastric ulcers is more distant but exists.

8. The hormonal and neurotransmitter cascade triggered by kissing includes adrenaline (which increases heart rate), endorphins (which produce euphoria), oxytocin (which helps development attachment), serotonin (which affects mood) and dopamine (which helps the brain process emotions). Your heart rate increases, your blood vessels dilate, your body receives more oxygen, and then all sorts of other parts of your body kick in. Your earlobes swell.

9. When kissing, cortisol levels drop for both sexes, meaning that kissing does in fact reduce stress. During kissing-under-laboratory conditions, oxytocin rises for males but unexpectedly drops for females. Neuroscientist Wendy Hill speculates this means that to bond, females may require a more romantic atmosphere than the experimental setting provided. Hill presented a paper recently at the American Association for the Advancement of Science annual meeting titled “Kissing Chemicals: Hormonal Changes in Responses to Kissing.”

10. Very few creatures other than humans are great kissers. The marked exceptions are our close relatives the chimpanzees and bonobos. Chimps, in fact, engage in kissing and making up after conflict.