February 14, 2009

Kissing Eases Stress Levels

Researchers have found that kissing unleashes chemicals that ease stress hormones in both sexes and encourages bonding in men, though not so much in women, according to the Associated Press.

Wendy Hill, a professor of neuroscience at Lafayette College, told a meeting of the American Association for the Advancement of Science on Friday that chemicals in the saliva might be a way to assess a mate.

A study involving 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, Hill said.

Their blood and saliva levels of the chemicals were compared before and after the kiss, where the researchers observed both men and women showed a decline in cortisol after smooching, an indication their stress levels declined.

Hill's team was surprised to find that, for men, oxytocin levels increased, indicating more interest in bonding. But oxytocin levels actually went down in women.

They found that chemical changes were similar, but much less pronounced in a test group that merely held hands.

Hill conducted the experiment in a student health center, noting that she plans to repeat follow-ups in a "more romantic setting."

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

Over 90 percent of human societies practice kissing, which Fisher believes has three components - the sex drive, romantic love and attachment.

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

Fisher said males tend to think of kissing as a prelude to copulation, noting 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 said. "If you kiss the right person, romantic love can last a long time."

Hill concluded that the science of kissing, or philematology, as it is known, is under-researched in academic fields.


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