Touch: The Science of Hand, Heart and Mind by David Linden - touching behaviour

by David Linden
Viking

How is it that a child can be born deaf or blind and yet grow up to be emotionally and physically healthy; but if a child is deprived of an early nurturing touch, he or she will suffer emotional, psychiatric and physical problems - obesity, type 2 diabetes, heart disease, immune and digestive disorders - that will last into adult life? Author David Linden has the answer in this engrossing book.

"Touch," says the neurobiologist at Johns Hopkins University in Baltimore, Maryland, "is not optional for human development … From consumer choice to sexual intercourse, from tool use to chronic pain to the process of healing, the genes, cells and neural circuits involved in the sense of touch have been crucial to creating our unique human experience."

It is apparently the first sense we develop in the womb. And not only does touch radically affect development, but it also creates and reinforces social bonds, inspires loyalty, encourages co-operation and enthuses sports teams. (A 2010 study found that basketball teams that celebrated successful play with hugs and high-fives became more successful as the season progressed.) Our skin is primed with sensors, some of which detect mechanical stimuli, such as vibration and pressure, while free nerve endings respond to pain and temperature. These sensations are transmitted from the skin to the spinal cord and then to the brain, in regions known as the primary and secondary somatosensory cortices.

But here is where the story becomes really interesting. These somatosensory cortices report to the brain's emotional-processing areas, which is why our tactile experiences come laced with meaning. Context is important. "… The feeling of a finger tracing our lips is delightful and arousing in a romantic setting with a lover but decidedly unerotic when it takes place in the doctor's office," Linden writes. Shakespeare puts it succinctly when Cleopatra speaks of "a lover's pinch/ Which hurts and is desired".

The really exciting revelations are about human behaviour. Waiting staff who gently touch their customers apparently receive larger tips. Doctors who touch their patients are rated as more caring, and their patients have better medical outcomes. Even people with clipboards at the mall are more likely to get you to sign their petitions or take their surveys if they touch your arm lightly.