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 early nurturing touch he or she will not only suffer emotional and psychiatric difficulties but also physical problems – obesity, type-two diabetes, heart disease, immune and digestive disorders – that will last into adult life? David J Linden, a neurobiologist at Johns Hopkins University in Baltimore, Maryland, answers this question in this engrossing book.
“Touch,” he commandingly asserts, “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 individual development but it 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 early in the season became more successful as the season progressed.)Our skin, we learn, is primed with sensors, some of which detect mechanical stimuli, such as vibration and pressure, while free nerve endings respond to temperature and pain. These sensations are transmitted from the skin to the spinal cord and thence to the brain, in regions known as the primary and secondary somatosensory cortices.
But here is where the story becomes really interesting, as these somatosensory cortices report to the brain’s emotional-processing areas, which is why our tactile experiences come laced with meaning. Context is important. “For most of us, 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.” Shakespeare puts it succinctly when Cleopatra speaks of “a lover’s pinch/ Which hurts and is desired”.
There are the inevitable similarities with primates. Chimpanzees “are more likely to respond to a distress call (thereby putting themselves in danger) when the call was recorded from an animal with which they recently groomed”. And there’s some good stuff on vampire bats whose blood-sucking enterprises benefit from three nasal pits. But the really exciting revelations are about our human behaviours. Waiting staff who gently touch their customers apparently receive larger tips (though I can imagine that going the other way). “Doctors who touch their patients are rated as more caring, and their patients have reduced stress-hormone levels and 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.”
Still more fascinating, the effect of a warm drink can radically alter our assessments of people and situations, which is why the old Jewish panacea of chicken soup is likely to be a genuine pick-me-up. Less comforting is the news that torturers recognise that the anticipation of pain increases its physical impact. Linden discourses entertainingly on the myriad ways in which touch informs our vocabulary. We speak of people or events as “touching”. We “itch” to slap someone. We “ache” with desire.
This book has changed my own life in a small but significant way. My family joke that I’m the woman who put the “sal” into “salad” as I’ve spent my life grazing on uncooked veg. I now gulp down hot soup and feel the better for it. Thank you, David Linden.
Salley Vickers’s new book, The Boy Who Could See Death, is published by Viking next month. Touch is published by Viking. Click here to buy it for £13.59
