Touch is the first of the senses to develop in the human infant, and it remains perhaps the most emotionally central throughout our lives.
When Nicolae Ceaușescu came to power, in the mid-nineteen-sixties, Romania saw the proliferation of leagăne—literally, “cradles,” otherwise known as institutional homes for the very young. Ceaușescu wanted to increase Romania’s industrial output, and he thought that that required a larger population. In 1966, he enacted Decree 770, which restricted contraceptives, banned almost all abortions for women who hadn’t had at least four children, and instituted a thirty-per-cent income tax on childless men and women who were over the age of twenty-five. In the span of a single year, the birth rate rose by thirteen per cent and the infant population nearly doubled. But even that wasn’t enough: in 1985, the dictator raised the minimum number of children to five and the age of the women covered by the decree from forty to forty-five. The result was one of the saddest natural experiments in modern psychology. Thousands of children, from birth to the age of three, grew up neglected in understaffed institutions, often experiencing severe sensory deprivation in their formative months.
Few people outside Romania initially knew about the leagăne. But when Ceaușescu was deposed, in 1989, images of the children reached television screens around the world. In 1994, Mary Carlson and her husband, Felton Earls, travelled to Romania to learn more about the effects of maternal deprivation on these children.* Carlson is a neurobiologist at Harvard Medical School, and Earls is a Harvard psychiatrist. A former student of Harry Harlow, the psychologist who is best known for his studies of socially deprived monkeys, Carlson, as she and Earls later wrote, found familiar “the muteness, blank facial expressions, social withdrawal, and bizarre stereotypic movements of these infants.” These behaviors “bore a strong resemblance” to the types of reactions that Carlson had seen in socially deprived monkeys and chimpanzees. She was also aware of studies of rats that showed how tactile stimulation could affect levels of the stress hormone cortisol during early development.
At a leagăne in the Romanian city of Iași, a child-development specialist named Joseph Sparling had organized a yearlong early-enrichment program for a group of infants, sparing them from the severe neglect and sensory deprivation typical of care in these institutions. The child-to-caregiver ratio for the children in the program was four to one, compared with the institutional standard of twenty to one. Carlson and Earls measured the cortisol levels of the enriched children, as well as of children in a control group. They took saliva samples multiple times a day, tracking how cortisol levels fluctuated over time and in response to stressful events. The levels of the children in the control group, they found, were off kilter, while the levels of the enriched children were more like those of Romanian children who had been home-reared. Cortisol in children who are home-reared tends to peak just before they wake up and then taper off; in the leagăne infants of the control group, cortisol peaked in the afternoon and remained elevated. That pattern, in turn, correlated with lower performance on numerous cognitive and physical assessments. By contrast, the children in Sparling’s enrichment program, who were receiving higher-quality care and more attention, performed better both physically and behaviorally.
In 1997, Carlson and Earls published their results. “The implications for the cognitive and social development of future generations of adults in this society are potentially serious when one considers that most Romanian children spend significant amounts of time in some form of institutional setting,” they wrote. In a subsequent interview, Carlson said of the study, “When the enriched kids returned to the typical conditions that involved little touching, the physical and behavioral advantage they had obtained faded. Although the enriched group showed a better response to stress as long as eighteen months later, they still were socially withdrawn and failed to respond normally to other children and adults.”
Touch is the first of the senses to develop in the human infant, and it remains perhaps the most emotionally central throughout our lives. While many researchers have appreciated its power, others have been more circumspect. Writing in 1928, John B. Watson, one of the originators of the behaviorist school of psychology, urged parents to maintain a physical boundary between themselves and their children: “Never hug and kiss them, never let them sit on your lap. If you must, kiss them once on the forehead when they say goodnight. Shake hands with them in the morning. Give them a pat on the head if they have made an extraordinarily good job on a difficult task.” Watson acknowledged that children must be bathed, clothed, and cared for, but he believed that excessive touching—that is, caressing—would create “mawkish” adults. An untouched child, he argued, “enters manhood so bulwarked with stable work and emotional habits that no adversity can quite overwhelm him.” Now we know that, to attain that result, he should have suggested the opposite: touch, as frequent and as caring as possible.
Like our other senses, touch comes in gradations. It is governed by an exquisite array of receptors that can distinguish minute variations in the external environment. Fast, slow, or in between? Hard, soft, or something else? Hot, cold, warm? Some receptors react only to caresses. Some send pain signals. Some tell us that we have an itch. Each type activates a different part of the brain, making us feel soothed or hurt, comfortable or distressed, angry or calm. In his recent book “Touch: The Science of Hand, Heart, and Mind,” the Johns Hopkins University neuroscientist David Linden cites “the electric touch of romantic love, the unsettling feeling of being watched, the relief of pain from mindful practice, or the essential touch that newborns need to thrive.” All of these diverse sensations, he writes, “flow from the evolved nature of our skin, nerves, and brain.”
The evolutionary psychologist Robin Dunbar has found that, among other primates, the frequency of grooming is a consistent proxy for group size and coherence. Similarly, among humans, touch might seem to serve as little more than a proxy for social bonds: if we often experience friendly or loving caresses, it’s safe to assume that we have a strong social network, which is itself one of the best predictors of happiness, health, and longevity. It’s easy to see how an elderly person who is regularly visited by a massage therapist might be happier and healthier than one who isn’t—even if the massage, as such, does nothing. In the case of the Romanian infants, it’s easy to imagine that a child who has a steady caretaker will be emotionally stronger than a child who languishes, abandoned, for long stretches of time—whether or not that caretaker takes particular pains to cuddle. It could be, in short, that the benefits of touch are really social benefits.
In fact, though, researchers have discovered that touch need not be social to be effective. In her more than thirty years of research on touch, Tiffany Field, the head of the Touch Research Institute at the University of Miami’s Miller School of Medicine, has sought repeatedly to disentangle the two. In one series of studies, one group of elderly participants received regular, conversation-filled social visits while another received social visits that also included massage; the second group saw emotional and cognitive benefits over and above those of the first. Field has found similar gains in both premature and full-term infants, pregnant women, children and adults with chronic pain conditions or emotional problems, and healthy adults. Even short bursts of touch—as little as fifteen minutes in the evening, in one of her studies—not only enhance growth and weight gain in children but also lead to emotional, physical, and cognitive improvements in adults. Touch itself appears to stimulate our bodies to react in very specific ways. The right kind can lower blood pressure, heart rate, and cortisol levels, stimulate the hippocampus (an area of the brain that is central to memory), and drive the release of a host of hormones and neuropeptides that have been linked to positive and uplifting emotions. The physical effects of touch are far-reaching.
And yet touch is rarely purely physical. Field’s more recent work has shown that the brain is very good at distinguishing an emotional touch from a similar, but non-emotional, one. A massage chair is not a masseuse. Certain touch receptors exist solely to convey emotion to the brain, rather than sensory information about the external environment. A recent study shows that we can identify other people’s basic emotions based on how they touch us, even when they are separated from us by a curtain. And the emotions that are communicated by touch can go on to shape our behavior. One recent review found that, even if we have no conscious memory of a touch—a hand on the shoulder, say—we may be more likely to agree to a request, respond more (or less) positively to a person or product, or form closer bonds with someone.
In real-world interactions, of course, we always experience touch in context: it can be hard, if not impossible, to separate its physical and emotional effects. In one set of studies, out this month, touch was shown to boost the immune systems of people who had been exposed to the common cold. For two weeks, researchers monitored a little more than four hundred adults, asking them not just about their social interactions but about how many hugs they’d gotten over the course of each day. Then the subjects were quarantined in rooms on an isolated hotel floor, where the researchers proceeded to expose them to a cold virus. The virus was quite effective: seventy-eight per cent of subjects were infected, and just over thirty-one per cent showed signs of illness. But not everyone was equally susceptible. The people who had experienced more supportive social interactions battled infection more effectively and exhibited fewer signs of illness—and, when you tease apart the effects of social support and hugging, touch, in itself, accounted for thirty-two per cent of the reduction effect.
“Stress is an explicitly biological phenomenon,” David Linden said when I asked him about the work, which came out after his book was complete. “The body talks to the brain, the brain to the body. The notion that someone’s immune status could be modified by activity in touch-sensitive regions of the brain is not at all crazy. One could certainly imagine a cellular-level explanation for how that would happen.” The more we learn about touch, the more we realize just how central it is in all aspects of our lives—cognitive, emotional, developmental, behavioral—from womb into old age. It’s no surprise that a single touch can affect us in multiple, powerful, ways.
The positive implications of this kind of research have yet to make it out of the lab and permeate our thinking. Even as the evidence increases, we continue to undervalue touch. Recently, the Toronto District School Board warned its employees that “there is no safe touch when you work with children.” Many of our kids spend most of the day in a touch-free zone. We don’t mind getting a massage, but we fear embracing touch wholeheartedly, either because we think it’s dangerous, in the case of young children, or “touchy-feely,” in the case of adults. We await what Tiffany Field, in 1998, called “a shift in the social-political attitude toward touch.”
In the meantime, scientists are pushing their research even further. As our understanding of the physiological mechanisms of touch grows, so, too, does the medical potential to treat touch-related conditions more directly. “Right now, we have good drugs to blunt pain, but with terrible side effects. But what if we could just block pain, without the euphoria of things like morphine or the bowel disruption of so many medicines?” Linden said. “If you start to identify the specific molecules involved in pain circuits, it’s a heck of an opportunity.” He pointed to testing on recently identified genes that are central to our touch circuitry, such as SCN9A, which is strongly expressed in pain receptors. Itch is another ailment in need of more effective treatments; one of Linden’s Johns Hopkins colleagues, Xinzhong Dong, a molecular geneticist who studies pain, is now investigating it, with an eye toward future drug therapies. “There’s enormous progress, potential, and excitement here,” Linden said. We are just—as it were—scratching the surface.