Hugh Pickens writes writes: Just in time for Valentine's day, the Pittsburg Post-Gazette reports kissing has an important biological function because the chemical information exchanged during a kiss — the unleashing of a "chemical choir" of assorted hormones in the brain — is sufficient to assess and rule out long-term mating potential as the body experiences a rise in chemicals including oxytocin, dopamine, serotonin and adrenaline — the stuff that creates a feeling of euphoria, attachment and excitement. "Behind a kiss is a very rich and complicated exchange of tactile cues, odors and other sensations that we seem to be hard-wired to process," says Dr. Gordon Gallup, one of the foremost researchers into romantic attraction, which, he admits is "not a very big field." But a kiss is not just about exchanging hormones, says Helen Fisher, a noted Rutgers University anthropologist and author of books on the science of romantic attraction. "It's really exchanging a huge amount of social information, too, about daily habits and intentions," she said. "You can see, smell, taste, hear and feel the other person, and you may be thinking, 'oh, he smells good, he must be very clean.' Then again, he may smell of cigarettes, and you think, 'oh, no, that's not good.' Or he may be coming on too strong, and you tell him to take it easy, and he does, and you think, 'Oh, he's a good listener.' " Women, it seems, gather more information from kissing than men do and are more likely to consider a good kiss critical to determining the future of the relationship. Men, not so much. "I would say on Valentine's Day, and every day, it is important," says says Sheril Kirshenbaum, a research scientist at the University of Texas in Austin. "It is the ultimate way to express yourself beyond what words can do."