The Psychology of Sex
EROTIC SEXUALISM AND THE BRAIN. Some years ago, when I visited the Yerkes primate laboratory in Atlanta, Georgia, I saw a newborn chimpanzee in an incubator of the type used for premature human babies. It was there because its captive, imprisoned mother did not know how to keep it alive. Like a human baby in an incubator, it was dressed only in diapers. How, I asked, did a wild chimpanzee mother keep its baby clean from soiling? The answer was that, as in many other species, she licks it clean, just as she licks it clean at birth, bites the umbilical cord, and eats the placenta.
Some months later, I had the chance to ask Margaret Mead if she knew of any societies in which human mothers do the same as do chimpanzee mothers in keeping their babies clean. Her answer was no. Among the people of Bali, in Indonesia, however, small dogs lick the babies clean. When a Balinese mother carries her baby on her thigh in a cloth hammock slung from her shoulders, she is accompanied by her pet dog. The dog’s assigned duty is to provide diaper service by licking clean the baby, and the mother, whenever the baby soils. Subsequently I have learned that Eskimo mothers once had a custom of licking their babies clean.
Even though human primates have graduated from using the mother’s snout end to keep the baby’s tail end clean, it is safe to assume that, as a species, we still possess in the brain the same phyletic circuitry for infant hygiene as do the subhuman primates. Just as males and females have nipples, so also do both sexes have these brain pathways that relate to drinking urine and eating feces. These are the pathways that, when they become associated with neighboring erotic/sexual pathways, produce urophilia and coprophilia as paraphilias.
John Money, Love and Love Sickness: The Science of Sex, Gender Difference and Pair-bonding, p. 98. John Hopkins University Press (Baltimore, London) 1980.