Roberto, now almost 6 years old, is one of a couple of dozen people in the United States with "congenital insensitivity to pain with anhidrosis," or CIPA--he was born without a sense of touch. More than half of all children born with CIPA--the most severe type of sensory neuropathy--die from heat stroke before age 3. Those who live must be on constant alert for unfelt injury; they may walk on a broken leg, or stay in the cold after frostbite's set in. And a lover's caress will never make them shiver with delight.
Of all our senses, touch is certainly the most essential to survival. And interestingly, being touched may be almost as critical.
Duke neurologist Saul Schanberg first started thinking about the power of touch after meeting children with psychogenic dwarfism, the stunting of growth that occurs after extreme emotional deprivation. Children who were ignored at home--both emotionally and physically--just stopped growing. Not only that but, as Diane Ackerman explains in her charming, poetic book, A Natural History of the Senses:
Schanberg found that even growth-hormone injections couldn't prompt the stunted bodies of such children to grow again, but tender loving care did. The affection they received from the nurses when they were admitted to a hospital was often enough to get them back on the right track. What's amazing is that the process is reversible at all.Ackerman goes on to discuss premature infants, who gain weight at a much faster rate when physically massaged by parents, nurses, and hospital volunteers. Schanberg's experiments on rats showed this happens in the opposite direction, too: when an infant rat was denied its mother's touch, even for as little as 45 minutes, it lowered its food intake and slowed its metabolism, presumably to save energy until the mother returned. But if she didn't come back at all, the baby rats stopped growing.
This evolutionary importance of touching and being touched may also explain why it makes us feel just so damn good. As Schanberg told Ackerman, "It's ten times stronger than verbal or emotional contact, and it affects damn near everything we do. No other sense can arouse you like touch...We forget that touch is not only basic to our species, but the key to it."
Wikipedia on Psychogenic Dwarfism