CHICAGO – "Chemistry look what you've done to me," Donna Summer crooned in
 Science of Love, and so, it seems, she was right. Just in time for Valentine's  Day, a panel of
 scientists examined the mystery of what happens when hearts throb and lips lock. Kissing, it
 turns out, unleashes chemicals that ease stress hormones in both sexes and encourage
 bonding in men, though not so much in women.

 Chemicals in the saliva may be a way to assess a mate, Wendy Hill, dean of the faculty and a
 professor of neuroscience at Lafayette College, told a meeting of the American Association
 for the Advancement of Science on Friday.

 In an experiment, Hill explained, pairs of heterosexual college students who kissed for 15
 minutes while listening to music experienced significant changes in their levels of the chemicals
 oxytocin, which affects pair bonding, and cortisol, which is associated with stress. Their
 blood and saliva levels of the chemicals were compared before and after the kiss.

 Both men and women had a decline in cortisol after smooching, an indication their stress
 levels declined.

 For men, oxytocin levels increased, indicating more interest in bonding, while oxytocin levels
 went down in women. "This was a surprise," Hill said.

 In a test group that merely held hands, chemical changes were similar, but much less
 pronounced, she said.

 The experiment was conducted in a student health center, Hill noted. She plans a repeat "in a
 more romantic setting."

 Hill spoke at the session on the Science of Kissing, along with Helen Fisher of Rutgers
 University and Donald Lateiner of Ohio Wesleyan University.

 Fisher noted that more than 90 percent of human societies practice kissing, which she
 believes has three components — the sex drive, romantic love and attachment.

 The sex drive pushes individuals to assess a variety of partners, then romantic love causes
 them to focus on an individual, she said. Attachment then allows them to tolerate this person
 long enough to raise a child.

 Men tend to think of kissing as a prelude to copulation, Fisher said. She noted that men
 prefer "sloppy" kisses, in which chemicals including testosterone can be passed on to the
 women in saliva. Testosterone increases the sex drive in both males and females.

 "When you kiss an enormous part of your brain becomes active," she added. Romantic love
 can last a long time, "if you kiss the right person."

 Lateiner, a classical scholar, observed that kissing appears infrequently in Greek and Roman
 art, but was widely practiced, despite the spread of skin disease at  that time by facial
 kissing. And there was a potential for social faux pas by kissing the wrong person at the
 wrong time.

 Overall, the science of kissing — philematology — is under-researcherd, Hill concluded.

 Courtesy of http://news.yahoo.com