Born to Be Good: The Science of a Meaningful Life

The scientific study of touch reveals the tactile modality to be an ideal medium in which individuals spread goodness to others. We can readily put touch to use in the close encounters of group living—when negotiating close spaces, working together, flirting amid rivals, playing around, or allocating scarce resources. Touch triggers biochemical reactions in the recipient—activation of the orbitofrontal cortex and deactivation of the amygdala, reduced stress-related cardiovascular response, and increased neurochemicals like oxytocin—all of which promote trust and goodwill between individuals. Touch, my studies show, is the primary language of compassion, love, and gratitude—emotions at the heart of trust and cooperation. To understand why touch can make jen viral, we must first look to evolution of the largest organ of the body—the epidermis—and that five-digit wonder, our hand.

SKIN AND HAND

 

In humans, shifts in the morphology of our organs of communication have emerged with developments in our ultrasociality. So it is with touch: Evolutionary shifts in our skin and hands have led to a central role of touch in our ultrasocial relationships. A first big shift was the loss of most of our body hair—we became, in Desmond Morris’s famous phrasing, naked apes. Why? You may be tempted by the aquatic ape hypothesis—that for a period of our evolution we actually lived largely in the water, thus losing our hair, as other water-bound mammals such as dolphins and whales did. As readily as this hypothesis appeals to our love of lolling about in the water on hot summer days and our sense of communion with whales and dolphins, it makes little evolutionary sense. As Nina Jablonski has argued in her book Skin, water holes on the African savannah were highly dangerous places, brimming with quick-striking predators, all the more so to a species not terribly adroit in the water, as in the case of our hominid predecessors. Had we been aquatic apes, we wouldn’t have done very well in the game of survival.

The actual explanation for our hair loss is less flamboyant but eminently more sensible—we lost our hair in hominid evolution for purposes of thermoregulation. A thick carpet of body hair would have been dangerously hot on the savannah—the locale of our early evolution. In this hot, arid environment, we increasingly relied on the rich network of sweat glands distributed throughout the skin to keep ourselves cool. These glands function more effectively in the absence of hair.

One by-product of this shift toward hairlessness is that our skin evolved into a most remarkable interface between our inner and outer worlds. Human skin is the largest of our organs, weighing six pounds and covering eighteen square feet. Its distinct layers house a veritable industrial zone of biological factories accomplishing several functions essential to human survival. A rich network of blood vessels, sweat glands, and hair follicles and surrounding muscles lie under the skin. There are cells producing proteins called keratins, which account for the strength and resilience of the skin. Cells known as immigrant cells move into the skin during development from other parts of the body and accomplish three tasks. Melanocytes produce the skin’s pigment, melanin, which protects our bodies from the dangers of ultraviolet rays. Langerhans cells are part of our immune system, and represent our body’s first response to viruses and bacteria. Finally, Merkel cells reside at the ends of sensory nerves in the skin and respond to touch. Some of these cells, in particular in the arm, face, and leg, appear to respond to slow, light touch, and may be involved in the release of opioids trigged by contact from others. The skin is our protection against harmful physical agents—sharp branches, ultraviolet rays, bacteria and viruses—in the external world. As important as the skin is to keeping the bad stuff out, it is vital to bringing the good stuff in.