The Power of Touch

You’re in a crowded subway car on a Tuesday morning, or perhaps on a city bus. Still-sleepy commuters, lulled by vibrations, remain hushed, yet silently broadcast their thoughts.

A toddler in his stroller looks warily at his fellow passengers, brows stitched with concern. He turns to Mom for reassurance, reaching out a small hand. She quietly takes it, squeezes, and releases. He relaxes, smiles, turns away—then back to Mom. She takes his hand again: squeeze and release.

A twenty-something in a skirt and blazer sits stiffly, a leather-bound portfolio on her lap. She repeatedly pushes a few blonde wisps off her face, then touches her neck, her subconscious movements both revealing and relieving her anxiety about her 9 a.m. interview.

A couple propped against a pole shares messages of affection; she rubs his arms with her hands, he nuzzles his face in her hair.

A middle-aged woman, squished into a corner, assuredly bumps the young man beside her with some elbow and hip. The message is clear; he instantly adjusts to make room.

Probing our ability to communicate nonverbally is hardly a new psychological tack; researchers have long documented the complex emotions and desires that our posture, motions, and expressions reveal. Yet until recently, the idea that people can impart and interpret emotional content via another nonverbal modality—touch—seemed iffy, even to researchers, such as DePauw University psychologist Matthew Hertenstein, who study it. In 2009, he demonstrated that we have an innate ability to decode emotions via touch alone. In a series of studies, Hertenstein had volunteers attempt to communicate a list of emotions to a blindfolded stranger solely through touch. Many participants were apprehensive about the experiment. “This is a touch-phobic society,” he says. “We’re not used to touching strangers, or even our friends, necessarily.”

But touch they did—it was, after all, for science. The results suggest that for all our caution about touching, we come equipped with an ability to send and receive emotional signals solely by doing so. Participants communicated eight distinct emotions—anger, fear, disgust, love, gratitude, sympathy, happiness, and sadness—with accuracy rates as high as 78 percent. “I was surprised,” Hertenstein admits. “I thought the accuracy would be at chance level,” about 25 percent.

Previous studies by Hertenstein and others have produced similar findings abroad, including in Spain (where people were better at communicating via touch than in America) and the U.K. Research has also been conducted in Pakistan and Turkey. “Everywhere we’ve studied this, people seem able to do it,” he says.

Indeed, we appear to be wired to interpret the touch of our fellow humans. A study providing evidence of this ability was published in 2012 by a team who used fMRI scans to measure brain activation in people being touched. The subjects, all heterosexual males, were shown a video of a man or a woman who was purportedly touching them on the leg. Unsurprisingly, subjects rated the experience of male touch as less pleasant. Brain scans revealed that a part of the brain called the primary somatosensory cortex responded more sharply to a woman’s touch than to a man’s. But here’s the twist: The videos were fake. It was always a woman touching the subjects.

The results were startling, because the primary somatosensory cortex had been thought to encode only basic qualities of touch, such as smoothness or pressure. That its activity varied depending on whom subjects believed was touching them suggests that the emotional and social components of touch are all but inseparable from physical sensations. “When you’re being touched by another person, your brain isn’t set up to give you the objective qualities of that touch,” says study coauthor Michael Spezio, a psychologist at Scripps College. “The entire experience is affected by your social evaluation of the person touching you.”

If touch is a language, it seems we instinctively know how to use it. But apparently it’s a skill we take for granted. When asked about it, the subjects in Hertenstein’s studies consistently underestimated their ability to communicate via touch—even while their actions suggested that touch may in fact be more versatile than voice, facial expression, and other modalities for expressing emotion.

“With the face and voice, in general we can identify just one or two positive signals that are not confused with each other,” says Hertenstein. For example, joy is the only positive emotion that has been reliably decoded in studies of the face. Meanwhile, his research shows that touch can communicate multiple positive emotions: joy, love, gratitude, and sympathy. Scientists used to believe touching was simply a means of enhancing messages signaled through speech or body language, “but it seems instead that touch is a much more nuanced, sophisticated, and precise way to communicate emotions,” Hertenstein says.

It may also increase the speed of communication: “If you’re close enough to touch, it’s often the easiest way to signal something,” says Laura Guerrero, coauthor of Close Encounters: Communication in Relationships, who researches nonverbal and emotional communication at Arizona State University. This immediacy is particularly noteworthy when it comes to bonding. “We feel more connected to someone if they touch us,” Guerrero notes.

There’s no phrase book to translate the language of touch; if anything, experts have barely begun documenting its grammar and vocabulary. “We found that there are many different ways to indicate a given emotion through touch,” Hertenstein notes. What’s more, how a touch gets interpreted is very context dependent. “Whether we’re at the doctor’s office or in a nightclub plays a huge role in how the brain responds to the same type of contact,” Spezio explains. Still, examining some of the notable ways that we communicate and bond through touch (and how we develop the capacity to do so) reveals the versatility of this tool and suggests ways to make better use of it. There’s much to be gained from embracing our tactile sense—in particular, more positive interactions and a deeper sense of connection with others.

Learning the Language of Touch

We begin receiving tactile signals even before birth, as the vibration of our mother’s heartbeat is amplified by amniotic fluid. No wonder then that touch plays a critical role in parent-child relationships from the start: “It’s an essential channel of communication with caregivers for a child,” says San Diego State University School of Communication emeritus professor Peter Andersen, author of Nonverbal Communication: Forms and Functions.

A mother’s touch enhances attachment between mother and child; it can signify security (“You’re safe; I’m here”) and, depending on the type of touch, it can generate positive or negative emotions. (Playing pat-a-cake makes infants happy, while a sudden squeeze from Mom often signals a warning not to interact with a new object). Mom’s touch even seems to mitigate pain when infants are given a blood test. University of Miami School of Medicine’s Tiffany Field, director of the Touch Research Institute, has linked touch, in the form of massage, to a slew of benefits, including better sleep, reduced irritability, and increased sociability among infants—as well as improved growth of preemies.

{Read More: The skin is a rich source of information about what we’re thinking and feeling.}

We’re never touched as much as when we’re children, which is when our comfort level with physical contact, and with physical closeness in general (what scientists call proxemics), develops. “The fact that there’s a lot of cultural variation in comfort with touch suggests it’s predominantly learned,” Andersen says.

Warm climates tend to produce cultures that are more liberal about touching than colder regions (think Greeks versus Germans, or Southern hospitality versus New England stoicism). There are a number of hypotheses as to why, including the fact that a higher ambient temperature increases the availability of skin (“It pays to touch somebody if there’s skin showing or they’re wearing light clothing through which they can feel the touch,” Andersen says); the effect of sunlight on mood (“It increases affiliativeness and libidinousness—lack of sunlight can make us depressed, with fewer interactions”); and migratory patterns (“Our ancestors tended to migrate to the same climate zone they came from. The upper Midwest is heavily German and Scandinavian, while Spaniards and Italians went to Mexico and Brazil. That influences the brand of touch”).

What goes on in your home also plays a role. Andersen notes that atheists and agnostics touch more than religious types, “probably because religions often teach that some kinds of touch are inappropriate or sinful.” Tolerance for touch isn’t set in stone, however. Spend time in a different culture, or even with touchy-feely friends, and your attitude toward touch can change.

By the time we’re adults, most of us have learned that touching tends to raise the stakes, particularly when it comes to a sense of connectivity. Even fleeting contact with a stranger can have a measurable effect, both fostering and enhancing cooperation. In research done back in 1976, clerks at a university library returned library cards to students either with or without briefly touching the student’s hand. Student interviews revealed that those who’d been touched evaluated the clerk and the library more favorably. The effect held even when students hadn’t noticed the touch.

More recent studies have found that seemingly insignificant touches yield bigger tips for waitresses, that people shop and buy more if they’re touched by a store greeter, and that strangers are more likely to help someone if a touch accompanies the request. Call it the human touch, a brief reminder that we are, at our core, social animals. “Lots of times in these studies people don’t even remember being touched. They just feel there’s a connection, they feel that they like that person more,” Guerrero says.

Just how strong is touch’s bonding benefit? To find out, a team led by University of Illinois at Urbana-Champaign psychologist Michael Kraus tracked physical contact between teammates during NBA games (consider all those chest bumps, high fives, and backslaps). The study revealed that the more on-court touching there was early in the season, the more successful teams and individuals were by season’s end. The effect of touch was independent of salary or performance, eliminating the possibility that players touch more if they’re more skilled or better compensated.

“We were very surprised. Touch predicted performance across all the NBA teams,” says Kraus. “Basketball players sometimes don’t have time to say an encouraging word to a teammate; instead, they developed this incredible repertoire of touch to communicate quickly and accurately,” he explains, adding that touch can likely improve performance across any cooperative context. As with our primate relatives, who strengthen social bonds by grooming each other, in humans, “touch strengthens relationships and is a marker of closeness,” he says. “It increases cooperation but is also an indicator of how strong bonds are between people.”

If a post-rebound slap on the back or the brush of a hand while delivering a bill can help us all get along a bit better, it may be because “when you stimulate the pressure receptors in the skin, you lower stress hormones,” says the Touch Research Institute’s Field. At the same time, warm touch stimulates release of the “cuddle hormone,” oxytocin, which enhances a sense of trust and attachment.

The release also helps explain our propensity for self-caressing, which we do hundreds of times each day as a calming mechanism. “We do a lot of self-touching: flipping our hair, hugging ourselves,” Field notes. Other common behaviors include massaging our foreheads, rubbing our hands, or stroking our necks. Evidence supports the idea that it’s effective: Self-massage has been shown to slow the heart rate and lower the level of the stress hormone cortisol.

A Touch of Love

Every evening at bedtime, DePauw’s Hertenstein gives his young son a back rub. “It’s a bonding opportunity for the two of us. Oxytocin levels go up, heart rates go down, all these wonderful things that you can’t see.” Moments like these also reveal the reciprocal nature of touch, he says: “You can’t touch without being touched. A lot of those same beneficial physiological consequences happen to me, the person doing the touching.”

In fact, when we’re the ones initiating contact, we may reap all the same benefits as those we’re touching. For example, Field’s research has revealed that a person giving a massage experiences as great a reduction in stress hormones as the person on the receiving end. “Studies have shown that a person giving a hug gets just as much benefit as a person being hugged,” she adds.

Moreover, touching another person isn’t just a one-way street when it comes to signaling; aside from sending them a message, it reveals a great of deal information about their state of mind, Hertenstein notes. Are they open to touch or do they pull away? Are they relaxed or tense? Are they warm—or perhaps cold and clammy? “Sometimes I’ll touch my wife and can tell instantly—even if my eyes are closed—that she’s stressed,” he says. “You can sense that through muscle tightness and contraction, and this kind of information can guide our behavior with that person—it influences what we think, how we perceive what they say.”

{Read More: How the physical sensations of objects we touch influence our more abstract feelings.}

Perhaps because touch affects both the person being touched and the one doing the touching, it is one of the most fundamental ways of fostering and communicating intimacy in a romantic relationship. One paper proposed a sequence of 12 behaviors of increasing intimacy that couples generally follow:

After the first three (eye-to-body contact, eye-to-eye contact, and speaking), the remaining nine involve touching (starting with holding hands, then kissing, and eventually sexual intimacy). “Touch functions a bit differently depending on the stage of the relationship,” says Guerrero. “In the beginning, it’s kind of exploratory. Will the other person reciprocate if I touch?” As the relationship progresses, touching begins to spike. “You see lots of public touch,” she notes, “people holding hands the whole time they’re together or with their arms around each other’s shoulders. It signals they’re intensifying the relationship.”

But it would be a mistake to think that the amount of touching couples do continues to follow an escalating trajectory. Research involving observation of couples in public and analysis of their self-reports shows that the amount of touching rises at the beginning of a relationship, peaks somewhere early in a marriage, and then tapers off. Over time romantic partners adjust the amount of touching they do, up- or downshifting their behavior to move closer to their significant other’s habits. Inability to converge on a common comfort zone tends to derail a relationship early on, while among couples in long-term marriages, touching reaches an almost one-to-one ratio.

While couples who are satisfied with each other do tend to touch more, the true indicator of a healthy long-term bond is not how often your partner touches you but how often he or she touches you in response to your touch. “The stronger the reciprocity, the more likely someone is to report emotional intimacy and satisfaction with the relationship,” Guerrero says. As with many things in relationships, satisfaction is as much about what we do for our partner as about what we’re getting.

The Laws of Social Contact

The most important things we reveal through touch: “probably our degree of dominance and our degree of intimacy,” Andersen says. Take, for example, the handshake, one of the few situations in which it’s OK to make prolonged contact with a stranger. As such, it’s an important opportunity for sending a message about yourself. “A limp handshake signifies uncertainty, low enthusiasm, introversion,” Andersen says, while a viselike grip can be taken as a sign that you’re trying to dominate. “You want to have a firm but not bone-crushing handshake,” he advises, since it’s better to be perceived as overly warm than as a cold fish. “We like people to have a kind of medium-high level of warmth,” Andersen says. “A person who touches a lot says, ‘I’m a friendly, intimate person.’ More touch-oriented doctors, teachers, and managers get higher ratings.”

Still, outside of close relationships, the consequences of sending the wrong message also increase. “Touchy people are taking some risk that they might be perceived as being over-the-top or harassing,” says Andersen. “Physical contact can be creepy; it can be threatening.” Context matters, which is why we have rules about whom we can touch, where, and when. “Generally, from the shoulder down to the hand are the only acceptable areas for touch,” at least between casual acquaintances, according to Andersen. “The back is very low in nerve endings, so that’s OK too.”

Of course, there are other contextual considerations as well. Different cultures and individuals have different tolerance levels for touch. Same-sex and opposite-sex touches have different implications. Then there’s the quality of the touch, the duration, the intensity, the circumstances. “It’s a complex matrix,” Andersen says. A quick touch and release—like a tap on a cubicle mate’s shoulder to get her attention—no problem. But a stroke on the shoulder could be easily misinterpreted. (“Most cases of sexual harassment involve stroking touches,” notes Andersen.)

A touch will naturally seem more intimate if it is accompanied by other signals, such as a prolonged gaze, or if it is held an instant too long. Meanwhile, a squeeze on the arm could be a sign of sympathy or support, but if it doesn’t end quickly and is accompanied by intense eye contact, it can come across as a squeeze of aggression. Environment changes things too: On the playing field, a man might feel comfortable giving his teammate a pat on the butt for a job well done, but that congratulatory gesture wouldn’t do too well in the office.

Really, the only rule that ensures communicating by touch won’t get you into trouble is this: Don’t do it. Which is likely what it says in the employee handbook for your workplace. Still, leaving your humanity behind every time you leave home isn’t very appealing. Andersen’s slightly less stringent guidelines for touch: Outside of your closest relationships, stick to the safe zones of shoulders and arms (handshakes, high fives, backslaps), and in the office, it’s always better for a subordinate, rather than a superior or manager, to initiate.

If there’s a most appropriate time to communicate via touch, it’s probably when someone needs consoling. “Research shows that touch is the best way to comfort,” says Guerrero. “If you ask people how they’d comfort someone in a given situation, they tend to list pats, hugs, and different kinds of touch behaviors more than anything else. Even opposite-sex friends, for example, who usually don’t touch a lot so they won’t send the wrong signals, won’t worry about being misinterpreted,” she says.

Maybe that’s because there are times—during intense grief or fear, but also in ecstatic moments of joy or love—when only the language of touch can fully express what we feel.

Further Reading:

Surface Impact: How the physical sensations of objects we touch influence our more abstract feelings.

What Your Skin Reveals: The skin is a rich source of information about what we’re thinking and feeling—no touch required.

Photos by Henry Leutwyler

Facebook photo: Yeko Photo Studio/

The simplistic message that personal boundaries are being redrawn is a missed opportunity to think about how touch is supposed to work. This doesn’t need to draw on some idea of political correctness; it’s right there in the studies. None of the touch studies involved unwanted, unexpected, or unpredictable touch. For example, Field did a study to see whether the effects of massage therapy were different in people who had and had not experienced past sexual abuse, and there was no apparent difference—both groups saw similar benefits. But this should not be expected to apply to the way both groups would react if a man on the subway initiated a shoulder massage.

The unwanted hug is an act on a spectrum of submission that produces neurochemical responses similar to any other violation of autonomy, from having a credit-card number stolen to feeling your car lose traction on the highway. A perceived absence of control becomes a spilling of neurotransmitters from the brain into the blood. If a boundary is being redrawn, it’s around people’s ability to continue to make others feel that. The benefits of a hug evaporate when a person perceives it as aggression. The trove of pro-touch research involves consenting volunteers and professional researchers in controlled scenarios where the interaction isn’t loaded with potential for escalation, or imbued with subtext or meaning based on prior interactions. In the real world, the exact same touch might cause blood pressure and heart rate to increase, and stress hormones to surge.

If it can be said that touch has medicinal properties, then, like any medicine, touch is not good for everyone in every situation. To play the metaphor out: Appropriate dosages vary, and any particular responses are dependent on what’s already going on with that person. This is why many doctors start a medication at a low dose and monitor the patient’s response closely. If it’s well received, the doctor can titrate dosing up and, over time, be less vigilant about monitoring for adverse reactions.

The analogy, of course, isn’t perfect, but experts in platonic touch advise the same: Start with small gestures. Some people might recoil at a touch on the shoulder; others will reach back and touch yours. It is not some mysterious code that should scare people into simply never trying to touch anyone—but it is a code predicated entirely on power dynamics. Just because a person is not actively pushing someone else away does not mean that touch is well received. Active reciprocity may be the surest sign, though even that is imperfect.

If the current lexicon of physical touch feels too loaded with meaning, there is also room for innovation. Americans largely practice one of two types of hug: the full-body press that’s generally reserved for close relationships, or the “A frame” type: bending at the back, partially twisting, and barely even touching. There are many ways to deviate from the hug canon in less awkward and potentially even fun ways, Field noted, citing a book of hugs numbering more than 300 in type—written by someone named “Dr. Hug,” whose credentials I can’t verify. “We’re getting a lot of calls about cuddling groups,” Field said with some degree of marvel, “which I think is related to a decline in touch not just among strangers, but even among intimate couples.”

Touch can communicate 12 different emotions, from gratitude, to sympathy and love


“What is the good life?” is one of life’s most vexing questions. Knowing what makes us happy, and how to bring happiness to others, has been the bread and butter of philosophers since Lao Tzu and Aristotle. But the answer to this is not as complex as one might imagine. In fact, we need look no further than our own hands. The roots of human goodness are to be found in the nascent science of human touch.
Tactile communication involves a complex communicative system that has been shaped by millions of years of mammalian evolution. It includes the human hand, a five-digit dexterous wonder, which evolved to gesture, clasp, hold, use tools and touch. Touch is first processed by the skin, an organ made up of billions of cells, which sends neurochemical signals to a large region of the cortex – the somatosensory cortex – which brings to consciousness the precise nature of each tactile contact with the outer world, whether it is friend or foe, potential lover or letch, toxin or harmless element.
Early clues to how tactile contact is a foundation of the good life were found in studies of nonhuman primates, which spend upwards of 15 per cent of their waking hours grooming one another. They do so not to find nits or nats or curb the spread of disease, but instead to form alliances, in particular in trades of grooming for food. Primatologist Frans de Waal first made this point, noting that chimps systematically share food with those that groomed them earlier in the day. Touch is the basis of that primordial act of kindness – sharing food with non-kin.
As humans evolved into the most social of primates, touch became an even richer language enabling moral ties with others. Touch is a powerful, direct means by which we give to others. Empirical studies find that the right kind of touch, the reassuring pat on the back or warm embrace, elicits in the recipient the release of oxytocin, a neurochemical that promotes trust and co-operation. A soft touch to the arm elicits activation in the orbitofrontal cortex, a region of your frontal lobes that signals expected rewards of an action. Warm, friendly touches of appreciation make others feel esteemed, valued and good.
Warm, friendly patterns of touch also calm down the recipient’s neurophysiology of stress. In one study, simply holding the hand of a loved one deactivated stress-related regions of the brain when anticipating going through a stressful experience.
Researchers at Berkeley have sought to pinpoint how touch may be a language of moral connection. In a study led by Matthew Hertenstein, two strangers came to the lab and were separated by a barrier, preventing all forms of communication except touch through a small hole. One participant stuck their arm through a hole in the barrier, at which time the individual on the other side attempted to communicate 12 different emotions, one at a time, with brief touches to the other person’s forearm.

The emotions included gratitude, sympathy, and love – quintessential moral sentiments. After each touch, the recipient guessed what emotion was just communicated. In this study, subjects could detect gratitude, sympathy and love about 55 to 60 per cent of the time. This shows that as the day unfolds we can rely on touch to convey gratitude, sympathy and love with brief touches.
Given the rewarding and calming effects of touch, Michael Kraus and I sought to document whether touch enables teams to collaborate better. Sports teams are known for their ritualised touch – think of the celebratory piles of bodies of football players after a goal is scored. For seven months our research team coded all of the observed touches in games played by each team in the US National Basketball Association at the start of the 2008 season. More than 25 kinds of touch were coded, including high fives and fist bumps, bear hugs and embraces, flying hip bumps and chest bumps and raps to the head expressing approval. On average, each player touched his teammates for about two seconds during the game. Just two seconds.
But those brief touches mattered. The more a team’s players touched each other at the beginning of the season, the better the team played at the season’s end: they were more efficient with each possession on offence, helped each other out more on defence and hustled for loose balls. In the end, the high-touch teams won a couple more games during the season.

Still further analyses found that touch improved team performance even when controlling for whether or not the team was winning in the game that we coded, how well the team was expected to do in the preseason, and how much money the players were making. And remember: each player was only touching teammates on average for two seconds during the game.
There is an old philosophical tradition that holds that the keys to the good life are to be found in moral sentiments such as gratitude, compassion and awe. Champions of this perspective include Adam Smith, David Hume and Charles Darwin. Even these prescient thinkers would likely be surprised by the extent to which the good life rests in the simplest of actions: human touch.

Dacher Keltner is a professor of psychology at the University of California, Berkeley. He has served as a consultant to Google and Facebook and was psychology adviser on Inside Out.

Greater Good‘s latest video features our executive editor, Dacher Keltner, on the science of touch. Here, he elaborates on cutting-edge research into the ways everyday forms of touch can bring us emotional balance and better health.

A pat on the back, a caress of the arm—these are everyday, incidental gestures that we usually take for granted, thanks to our amazingly dexterous hands.

© Brian Jackson

But after years spent immersed in the science of touch, I can tell you that they are far more profound than we usually realize: They are our primary language of compassion, and a primary means for spreading compassion.

In recent years, a wave of studies has documented some incredible emotional and physical health benefits that come from touch. This research is suggesting that touch is truly fundamental to human communication, bonding, and health.

In my own lab, in a study led by my former student Matt Hertenstein (now a professor at DePauw University), we asked whether humans can clearly communicate compassion through touch.

Here’s what we did: We built a barrier in our lab that separated two strangers from each other. One person stuck his or her arm through the barrier and waited. The other person was given a list of emotions, and he or she had to try to convey each emotion through a one-second touch to the stranger’s forearm. The person whose arm was being touched had to guess the emotion.

Given the number of emotions being considered, the odds of guessing the right emotion by chance were about eight percent. But remarkably, participants guessed compassion correctly nearly 60 percent of the time. Gratitude, anger, love, fear—they got those right more than 50 percent of the time as well.

We had various gender combinations in the study, and I feel obligated to disclose two gender differences we found: When a woman tried to communicate anger to a man, he got zero right—he had no idea what she was doing. And when a man tried to communicate compassion to a woman, she didn’t know what was going on!

But obviously, there’s a bigger message here than “men are from Mars and women are from Venus.” Touch provides its own language of compassion, a language that is essential to what it means to be human.

In fact, in other research I’ve found that people can not only identify love, gratitude, and compassion from touches but can differentiate between those kinds of touch, something people haven’t done as well in studies of facial and vocal communication.

“To touch is to give life”
Regrettably, though, some Western cultures are pretty touch-deprived, and this is especially true of the United States.

Ethologists who live in different parts world quickly recognize this. Nonhuman primates spend about 10 to 20 percent of their waking day grooming each other. If you go to various other countries, people spend a lot of time in direct physical contact with one another—much more than we do.

This has been well-documented. One of my favorite examples is a study from the 1960s by pioneering psychologist Sidney Jourard, who studied the conversations of friends in different parts of the world as they sat in a café together. He observed these conversations for the same amount of time in each of the different countries.

What did he find? In England, the two friends touched each other zero times. In the United States, in bursts of enthusiasm, we touched each other twice.

  • More on Touch

    Check out this research on the positive effect of touch in schools, and learn how important touch is in communicating positive emotions.

But in France, the number shot up to 110 times per hour. And in Puerto Rico, those friends touched each other 180 times!

Of course, there are plenty of good reasons why people are inclined to keep their hands to themselves, especially in a society as litigious as ours. But other research has revealed what we lose when we hold back too much.

The benefits start from the moment we’re born. A review of research, conducted by Tiffany Field, a leader in the field of touch, found that preterm newborns who received just three 15-minute sessions of touch therapy each day for 5-10 days gained 47 percent more weight than premature infants who’d received standard medical treatment.

Similarly, research by Darlene Francis and Michael Meaney has found that rats whose mothers licked and groomed them a lot when they were infants grow up to be calmer and more resilient to stress, with a stronger immune system. This research sheds light on why, historically, an overwhelming percentage of humans babies in orphanages where caretakers starved them of touch have failed to grow to their expected height or weight, and have shown behavioral problems.

“To touch can be to give life,” said Michelangelo, and he was absolutely right.

From this frontier of touch research, we know thanks to neuroscientist Edmund Rolls that touch activates the brain’s orbitofrontal cortex, which is linked to feelings of reward and compassion.

We also know that touch builds up cooperative relationships—it reinforces reciprocity between our primate relatives, who use grooming to build up cooperative alliances.

There are studies showing that touch signals safety and trust, it soothes. Basic warm touch calms cardiovascular stress. It activates the body’s vagus nerve, which is intimately involved with our compassionate response, and a simple touch can trigger release of oxytocin, aka “the love hormone.”

In a study by Jim Coan and Richard Davidson, participants laying in an fMRI brain scanner, anticipating a painful blast of white noise, showed heightened brain activity in regions associated with threat and stress. But participants whose romantic partner stroked their arm while they waited didn’t show this reaction at all. Touch had turned off the threat switch.

Touch can even have economic effects, promoting trust and generosity. When psychologist Robert Kurzban had participants play the “prisoner’s dilemma” game, in which they could choose either to cooperate or compete with a partner for a limited amount of money, an experimenter gently touched some of the participants as they were starting to play the game—just a quick pat on the back. But it made a big difference: Those who were touched were much more likely to cooperate and share with their partner.

These kinds of benefits can pop up in unexpected places: In a recent study out of my lab, published in the journal Emotion we found that, in general, NBA basketball teams whose players touch each other more win more games.

Touch therapies
Given all these findings, it only makes sense to think up ways to incorporate touch into different form of therapy.

“Touch therapy” or “massage therapy” may sound like some weird Berkeley idea, but it’s got hard science on its side. It’s not just good for our muscles; it’s good for our entire physical and mental health.

Proper uses of touch truly have the potential to transform the practice of medicine—and they’re cost effective to boot. For example, studies show that touching patients with Alzheimer’s disease can have huge effects on getting them to relax, make emotional connections with others, and reduce their symptoms of depression.

Tiffany Field has found that massage therapy reduces pain in pregnant women and alleviates prenatal depression—in the women and their spouses alike. Research here at UC Berkeley’s School of Public Health has found that getting eye contact and a pat on the back from a doctor may boost survival rates of patients with complex diseases.

And educators, take note: A study by French psychologist Nicolas Gueguen has found that when teachers pat students in a friendly way, those students are three times as likely to speak up in class. Another recent study has found that when librarians pat the hand of a student checking out a book, that student says he or she likes the library more—and is more likely to come back.

Touch can even be a therapeutic way to reach some of the most challenging children: Some research by Tiffany Field suggests that children with autism, widely believed to hate being touched, actually love being massaged by a parent or therapist.

This doesn’t mean you should turn around and grope your neighbor or invade the personal space of everyone around you.

But to me, the science of touch convincingly suggests that we’re wired to—we need to—connect with other people on a basic physical level. To deny that is to deprive ourselves of some of life’s greatest joys and deepest comforts.

The Surprising Psychological Value of Human Touch

Whenever I’m overwhelmed or feeling down, I tend to crave touch. A hug, a hand to hold; a connection that can manifest into something that’s tangible. And even on stress-free days, I may seek out the healing components that touch has to offer.

Is the act of human touch an innate need, ingrained within? Not necessarily (in my opinion), but on a superficial level, it very well could be. Research demonstrates that touch contains several health benefits for our physiological and psychological well being.

A 2011 article on discusses the numerous positive effects associated with physical contact and affection.

Hugging induces oxytocin, the “bonding hormone,” that’s renowned for reducing stress, lowering cortisol levels and increasing a sense of trust and security. According to research conducted at the University of North Carolina, women who receive more hugs from their partners have lower heart rates and blood pressure and higher levels of oxytocin.

“Hugs strengthen the immune system,” according to a post on “The gentle pressure on the sternum and the emotional charge this creates activates the Solar Plexus Chakra. This stimulates the thymus gland, which regulates and balances the body’s production of white blood cells, which keeps you healthy and disease free.”

The CNN post notes that holding hands produces a calming response. James Coan, PhD, assistant professor of psychology at the University of Virginia, administered MRIs to 16 married women, relaying that they may experience a mild shock. The anxiety illustrated various brain activity, but when the women held hands with one of the experimenters, their stress dissipated — when they held hands with their husbands, stress decreased even further.

Coan observed that there was a “qualitative shift in the number of regions in the brain that just weren’t reacting anymore to the threat cue.” The article continues to state that, interestingly enough, hand clasping in happy relationships reduces stress-related activity in the hypothalamus region of the brain, which lowers cortisol levels throughout the system, as well as the area in the brain that registers pain.

Snuggling has the potential ability to bolster communication.

“Most people want to feel understood and communication is the vehicle by which they transmit understanding and empathy,” David Klow, a marriage and family therapist, said. “Non-verbal communication can be a very powerful way to say to your partner, ‘I get you.’ Cuddling is a way of saying, ‘I know how you feel.’ It allows us to feel known by your partner in ways that words can’t convey.”

Human touch — hugging, hand holding, cuddling, and other outlets of contact — can be beneficial, health-wise, physically and emotionally. (Oxytocin for the win!) And as I’m typing this, sifting through cold-recovery mode with a bit of laryngitis, I can’t help but think that a hug would be a great immunity booster at the moment. Hmmm…

The Surprising Psychological Value of Human Touch

The 3 Biggest Advantages of Human Touch May Surprise You

Table of Contents

These 3 Advantages of Hugs, Pats, or Intimacy May Surprise You

Have you ever wondered why holding hands, a hug, or cuddles can feel so good? From social reasons to health-boosting benefits, read on to find out how touch can be so soothing and increase your longevity.

Why Is Touch Important?

One of the most important parts of human heritage is the need for physical contact. This is especially important at birth when babies need to cry, suckle, and cling to their caregivers to help them survive and create bonding. Once kids are older, touch has been known to help with learning engagement. One study found that students are three times as likely to speak up in class after their teacher pats them in a friendly way.

It’s not only humans that need touch. Primates also often pick at each other’s fur throughout the day. For instance, it has been observed that the gelada baboon grooms for about 17 percent of its waking hours. Among the various reasons why primates do touch each other is to ease tensions among the group in social situations.

The hormone Oxytocin is another benefit of physical touch or acts of cuddling. Oxytocin helps humans connect to others and promotes feel-good sensations that foster a sense of well-being and happiness. Even if we aren’t bonding with babies, adults can still benefit from the various rewards of an oxytocin release with friends, partners, or even animals.

3 Positive Health Manifestations from Touch

The benefits of physical touch, and the biological releases that come with it, go beyond social bonding and can manifest positively in your mental and physical health. Here are some major ways being open to more hugs and hand holding can increase your happiness and longevity.

Inspire positive thinking and expand trust

Known as the “feel good” hormone, oxytocin helps inspire positive thinking and maintaining an optimistic outlook on the world. The role of oxytocin for bonding also extends to helping generate feelings of compassion during interactions. This can contribute to an expansion of trust among individuals during social situations.

Reduce social anxiety and stress

Physical touch increases levels of dopamine and serotonin, two neurotransmitters that help regulate your mood as well as help your body relieve stress and anxiety. Dopamine is also known to regulate the pleasure center in your brain that is a good counter to feelings of anxiety. One study on breast cancer patients found that massage therapy in the form of stroking, stretching, and squeezing helped relax participants and increase dopamine and seratonin levels.

Boost immune system and lower blood pressure

Physical touch is known to improve the function of your immune system as well as reduce diseases such as those associated with the heart and blood. One study on women found that receiving more hugs from their partners led to lower heart rates and blood pressure.

Ways to Get Your Physical Touch Boost

You don’t have to get hugs and cuddles exclusively from a significant other. Heart-to-heart hugs can feel satisfying and invoke the release of oxytocin even when you hug a friend, family member, or pet. Be aware of how much hugs and cuddles the other person is comfortable with. Like humans, pets may also have their preference of touch, so be mindful!

Depression Test

Before you go, check in on your mental health with our depression test below.

How Touching Your Partner Can Make Both of You Healthier

Whether it’s a few moments spent holding hands, a hug hello, or cuddling on the couch, simple touches from those we care about can bring a smile to our face — even on our most difficult days.

However, being touched by those we love doesn’t merely feel good. Studies show simple touch is also good for our mental and physical health.

“If someone holds your hand or hugs you or gives you a back massage before you have a stressful task like giving a speech, your heart rate slows, blood pressure lowers, and your stress hormones will decrease,” Tiffany Field, PhD, director of the Touch Research Institute at the Leonard M. Miller School of Medicine at the University of Miami, told Healthline. “There’s also an increase in oxytocin, which is the love hormone that contributes to relaxation in couples.”

As a result of de-stressing, research has shown soothing touch can also help build your immune system.

“There’s this whole body of literature around the stress response and how chronic stress literally impairs everything from brain functioning to your immune system. When you’re under a lot of stress, cortisol is released and your immune system tanks, allowing you to get sicker,” said Dr. Amy Banks, a psychiatrist based in Lexington, Massachusetts, and author of “Wired to Connect: The Surprising Link Between Brain Science and Strong, Healthy Relationships.”

To better understand the connection, Banks pointed to the evolution of humankind.

It begins with evolution

At one time, creatures gave birth to many eggs. When born, the creatures had to fend for themselves for survival, yet only few of the many would live on.

“Once we became mammals, we kept the babies inside of us and so we had fewer of them. Their chances of survival were dependent on us being in a social context — a parent taking care of their offspring,” Banks said. “Biologically, our whole nervous system and immune system functioning became dependent on being in a relationship, a society, a community, where the younger, smaller, weaker could be protected until they grew up.”

Around this time, she says the smart vagus nerve evolved. This is part of the autonomic nervous system and modulates the entire stress response system, called the sympathetic nervous system.

“The smart vagus nerve tells our sympathetic nervous system to stand down, you’re not needed,” explained Banks.

For instance, when a person feels safe and connected to another person, their facial expressions may create a smile, and the muscles in their inner ears open up, so that they listen more attentively. Both of these reactions are stimulated by the smart vagus nerve.

Touch and comfort are innate

From birth, babies have a desire for social connection. Banks pointed to the mother-infant gaze, which refers to the interactions between a mother and her baby in a healthy relationship.

“Literally the mother and infant become synchronized when they interact with each other,” said Banks. “As they engage, the baby gets stimulated and then looks away as a way to modulate the stimulation. In response, an in-tune mother will do the same thing. Then they’ll re-engage.”

She says this connection over the first few years of life helps to build the capacity for future safe relationships by building pathways for serotonin — the body’s anti-pain and antidepressant chemical — dopamine, oxytocin, and even opioids, which help the body regulate mood, affects, and even pain.

“The touch, the holding, and cuddling are all shown to stimulate these pathways needed for connection,” Banks said.

Consider the Harlow’s Monkey Experiment conducted by American psychologist Harry Harlow, which observed rhesus monkeys and how isolation and separation can affect them later in life. The experiment proved that creating a bond between a monkey and its mother required both physiological needs, such as warmth, safety, and food, as well as emotional needs including acceptance, love, and affection.

During the experiment, monkeys were taken from their mothers within 12 hours of being born and put into a room with inanimate mothers. One mother was made of wire mesh and one was made of wood covered in terry cloth. The monkeys could get milk from both.

In the first experiment, the monkeys were free to go to either of the moms, but spent more time cuddling with the terry cloth mother. In the second experiment, the monkeys were placed with one of the moms. When put into stressful situations, the monkeys with the terry cloth mom would cuddle with the mom until they calmed down. However, the monkeys placed with the wire mesh moms didn’t go to it for comfort, and instead rocked themselves on the ground.

Harlow suggested that these results also apply to humans.

“This shows how we are built. Touch does all this great stuff in terms of releasing chemicals and giving us comfort,” Banks said.

Christine Proulx, PhD, associate professor in the department of Human Development and Family Science at the University of Missouri, agreed, stating that from birth, we have a physiological response to touch.

“There’s a reason why there’s a big push to immediately put a baby on a mother’s chest and why people volunteer to hold babies in the neonatal intensive care unit. We’re hardwired for that skin-to-skin contact, and this carries over into adulthood,” Proulx said.

As adults, she said romantic relationships are one of the primary relationships that provide us with the touch we crave. “We ask for hugs because they benefit and soothe us, and so they have a health-promoting benefit in that sense,” she said.

Feeling connected also fends off loneliness, added Proulx. “There are lots of studies on how isolation and loneliness are detrimental to our health. Most human beings want to feel that someone loves and cares for them. Our close relationships can fill that desire,” she said.

For couples who are particularly close, Fields adds that touching can sync their physiological rhythms. “When they hold hands, their heart rates are in sync and their brain waves get in sync. It’s a phenomenon that happens,” Field said.

Emotional benefits are also intertwined.

“There are a lot of feelings that go along with receiving touch from your partner and most are positive feelings reflected in brain waves,” Fields said.

While the right front lobe is activated during negative or withdrawal-type emotions, the left side of the frontal lobe usually causes positive emotions.

“It’s been documented that the pleasure part of the brain is activated during touch,” said Fields.

In addition to the physiological and emotional benefits, Proulx says there’s also a practical component to feeling cared for and connected.

“If something happens, who can you call? If you fall and have no one to reach out to, your health is at risk. Feeling cared for certainly has an instrumental side to it too,” she said.

What about sexual contact?

When sexual interactions are safe and consensual, Banks said people get all the benefits of touch too.

“There’s very good research that shows being in that kind of sexual encounter has tons of benefits. For example, you get big releases of oxytocin when you have an orgasm,” she said.

However, the same hormones are at play with nonsexual touching, such as cuddling, back rubs, back scratches, foot rubs, and holding hands. “All of these stimulate the same chemicals, maybe not at the same intensity , but clearly they’re released,” Banks said.

Hands-on health

So, the next time you reach for your partner’s hand, embrace them after a long day, or snuggle during a movie, remember, you’re not just showing them you care — you’re both getting a health boost too.

The Scientific Benefits of Human Touch

Sharp. Painful. Orgasmic. Comforting. Touch can be any of these things. But, it’s much more than one of the classic five senses; it’s fundamental to everything we think and feel, how we communicate and bond, and whether or not we catch a cold.

It all starts in the bottom layer of our skin. There, a series of informational conveyor belts, called Merkel cells, feed data from the skin to the body’s central nervous system. The body then responds with a surge of hormones. And, if you’re receiving the right kind of touch-as opposed to a creepy one or a punch in the nose-you’ll get a dose of oxytocin, the aptly named “cuddle hormone.”

The results are palpable. Spearheaded by labs throughout the country that are dedicated to the science of touch, a slew of new studies are proving that touch-gentle, empathetic, and supportive-comes with incredible emotional and physical health benefits. “Touch is our body’s largest and the oldest sense,” says Jeanne AbateMarco, M.S., R.N., C.N.S., clinical nurse coordinator of the Department of Integrative Health Programs at NYU Langone Medical Center. “It’s a channel of communication. It’s integral to the human experience.”

But no two touches are the same. Head to Refinery29 to learn how touch-from your partner, best friend, personal trainer, M.D., massage therapist, Fido, or robot (if you’re into that)-affects your health.

  • By Refinery29


How does human touch work?

‘There are various chemicals that are stimulated by physical touch, both in the giver and receiver – the feel-good chemical oxytocin is one of those chemicals,’ Gordon explains. ‘We have receptors in our skin that go to the brain.’

When touch is given appropriately, the benefits affect everyone from newborns and new mums to the elderly and isolated.

Newborn development: Skin-to-skin contact

We know for babies, skin-to-skin contact is essential for physical and psychological development. Research published in the journal Biological Psychiatry shows the benefits of human touch as a newborn are measurable even 10 years after birth.

In this study, 73 premature babies were given maternal skin-to-skin contact and were compared to 73 babies who received incubator care. After repeated testing, from aged 6 months to 10 years, those in the skin-to-skin group were found to have greater cognitive skills. At 10 years of age, these children also had better sleep patterns, physical responses to stress, more advanced autonomic nervous systems and better cognitive control.

Gordon says the release of oxytocin triggered by touch is an important chemical for mums as well as newborns. It has been shown that parent/child infant massages lifted low moods in new mums with postnatal depression and helped them connect with their babies.

Healing hugs for health and wellbeing

Regular hugs can also have a big impact on our health and wellbeing. One study showed frequent hugs between partners were associated with lower blood pressure and heart rates, and higher oxytocin levels in premenopausal women. The study also found those who hugged more often enjoyed better physical and psychological health, improved relationships and were better able to handle conflict.

Bonding through human touch

The benefits of human touch extend to making us feel more connected and socially accepted too. In one study, a group of NBA basketball players actually did better when they performed bonding gestures, such as back-slapping, bumping chests and exchanging high-fives on court. Researchers say this demonstrates the power of touch in communicating cooperation and trust.

Soothing and lowering stress

Experts know that touch can soothe and lower stress in babies, a rub on the back can lull children to sleep, hugs can make kids feel safe and accepted, and hand-holding can help in times of distress. This soothing effect has also been shown to help in aged-care settings.

Gordon points to one study in which people with dementia were given dolls to hold and stroke, to help soothe their agitation.

‘I would assume touch is playing that role, because there are receptors in the skin of our hands for who give as well as receive,’ she says.

‘Older people who are isolated, have been widowed or lost their partner, run the risk of being deprived of touch, and I’m sure that’s connected with a level of depression and anxiety.’

Gordon also reminds us of the benefits of touch when someone is at the end of life. ‘We are drawn to taking their hand and holding it, stroking it, and we know that, even though they may not appear receptive, it is likely to give some good to the receiver as well as the give.’

How to get your dose of human touch

If you don’t have access to regular hugs, there are other ways to get its feel-good benefits:

  • patting a furry friend has been found to release “happy hormones” oxytocin and serotonin
  • make the most of small gestures of connectedness with friends, teammates and people you come across in daily life
  • massage therapy is a great way to unwind.

If you feel disconnected and are lacking human touch, reach out to a professional, such as a GP you can refer you to a psychologist, to talk through your feelings. If you require urgent mental health support and emotional assistance, call Lifeline on 13 11 14.

9 surprising facts about the sense of touch

Touch is perhaps the most overlooked sense.

Every one of us receives tactile information about the world around us every second of the day. Right now, if you’re sitting, your butt is being squished into your chair. Your fingertips are probably touching a mouse, or swiping the glass of your phone. All this information is so omnipresent, in fact, that the only way to make sense of it is to tune most of it out — you probably weren’t paying attention to these sensations until you read those words.

“You can’t turn off touch. It never goes away,” says David Linden, a neurobiologist at Johns Hopkins and author of the new book Touch: The Science of Hand, Heart, and Mind. “You can close your eyes and imagine what it’s like to be blind, and you can stop up your ears and imagine what it’s like to be deaf. But touch is so central and ever-present in our lives that we can’t imagine losing it.”

In the book, Linden explores all sorts of fascinating aspects about this enigmatic sense. He recently spoke with me about some of what he’s learned.

1) Your brain pays wildly disproportionate attention to touch on different parts of your body

The cortical homunculus — a human figure scaled to match the proportions of how touch sensors are represented in the brain. (OpenStax College)

“The part of your brain that processes touch information has a map of your body surface. But this map is very highly distorted,” Linden says.

“It over-represents areas that have lots of fine touch receptors (like the face, the lips, the tongue, and the fingers) and under-represents areas that don’t have many receptors (like the small of your back, your chest, and your thighs).”

These receptors, he says, come in four varieties. “There’s one receptor for sensing vibration, one for tiny amounts of slippage, one for stretching of the skin, and one that senses the finest kinds of textures. The last one, called a Merkel ending, is only in the parts of your body you use to feel something really finely — like your fingertips and lips.”

2) Your sense of touch gets worse as you age


“From work in both humans and lab animals, we’ve found that areas of the touch-sensing parts of your brain that you use a lot tend to expand and take over neighboring territory,” Linden says. “So a violin player who uses her left hand more than her bowing hand will have the area of her brain that processes information from her left hand expand.”

“we all lose touch receptors over the course of our lives”

“But another interesting thing has to do with the effects of aging. It seems as though we all lose touch receptors over the course of our lives. It’s not like we have them until a certain age, then they suddenly disappear — we lose them very, very slowly. They peak around age 16 or 18, then disappear slowly.”

“You also lose pain and temperature receptors — which might actually be a good thing. It may be that when you’re older, you might not feel as much surface pain in your skin. But there are other interesting implications of this: it may be that part of the reason it becomes harder to achieve orgasm as you grow older is that touch receptors in the skin of the genitals become less dense.”

“This might also be one of the factors that lead the elderly to take falls. We stay upright in part because of sensations on the bottom of our feet, and we get less of that information the older we get.”

3) People can be “touch-blind”

“It’s amazing, because we don’t even have a word for lacking touch,” Linden says. “But touch-blindness is very real. I wrote about a woman named ‘G.L.’ who has a very rare disorder called primary sensory neuropathy. That means she’s lost all her sensors for mechanical touch.”

“She claims she can’t feel anything at all. She can’t read braille. If she puts her hands in her pockets, she can’t tell a penny from a quarter. But remarkably, if you get her in the lab, you find that she has one form of sensation left: if you caress her forearm, or her leg, or another area of skin, she can tell roughly where it is, and she knows it’s pleasant. That’s because she has retained a different, emotional touch system.”

4) You have a special system for feeling emotional, social touch


“There are two touch systems,” Linden says. “One that gives the ‘facts’ — the location, movement, and strength of a touch — and we call that discriminative touch.”

“But then there’s the emotional touch system. It’s mediated by special sensors called C tactile fibers, and it conveys information much more slowly. It’s vague — in terms of where the touch is happening — but it sends information to a part of the brain called the posterior insula that is crucial for socially-bonding touch. This includes things like a hug from a friend, to the touch you got as a child from your mother, to sexual touch.”

“It’s not just a different kind of information that’s conveyed by the same sensors in the skin that allow you to feel a quarter in your pocket. It’s a completely different set of sensors and nerve fibers that wind up in a different part of your brain.”

5) You also have a special system that makes pain hurt


“In the pain circuitry, there’s also one set of sensors that tells you exactly where the pain is, how strong it is, etc. And then, again, there’s another system that just conveys the negative emotional aspect of the pain,” Linden says.

“It’s the second system that can be modified by drugs, like morphine, or by meditative practice. And there are also some rare cases — people called ‘pain asymbolics’ — who lack the emotional pain system. So they have the ‘facts’ of pain, they’re aware of it, but it doesn’t bother them. If you stick their hand in a bucket of ice water (a standard way of inflicting pain in a lab), they know it hurts, but they don’t actually mind it.”

6) Touch is mysteriously crucial for a baby’s development


“The best examples of this come from Romanian orphanages after Ceaușescu’s fall, when there just weren’t enough people around to take care of babies. They were barely touched during the day,” Linden says.

“These kids didn’t just have a host of emotional problems — though they were depressed and had high instances of schizophrenia, bipolar disorder, and other issues — but they also had a whole raft of physical ailments. They had weakened immune systems, and skin ailments.”

“they had weakened immune systems and skin ailments”

“Other research has confirmed this phenomenon. We’re not entirely sure why it happens, but it seems that early touch experience is extraordinarily important for development both cognitive function and a healthy body.”

“This is why, nowadays, when premature infants are born and put in isolators, they’re taken out for a few hours a day, and pressed against a parent’s skin. Initially, when isolators were first invented, people thought you should just leave them in there alone, so they don’t get infected. But then they might not get touched for the first two months of life, which turns out to be disastrous.”

7) Touch shapes first impressions of people in weird ways


“Incidental touch can help form our impressions of people’s character,” Linden says. “In one of the classic experiments, people were holding either a cold iced drink or a hot drink when meeting someone, and those with a hot drink literally rated the people they met as warmer — as in, having a more pro-social personality. They didn’t rate them better overall — say, as smarter, or more competent — they just rated them as warmer.”

“There was another famous study in which people evaluated others’ resumes on a clipboard, and if they were on a heavy clipboard — rather than a really light one — they were rated as having more gravitas, more authority. Once again, people didn’t think they were smarter, or better team players, or things like that. The weight made them seem weighty.”

“those with a hot drink literally rated the people they met as warmer”

“When these studies first came out, no one really believed them — but they’ve since been well reproduced. It’s also not a quirk of English, it happens across cultures. It’s been done in Papua New Guinea.”

“It points to an idea that’s come up in social psychology again and again: if you’re evaluating someone for the first time, the first decision you make is friend or foe. Is this person warm, or are they a threat? Then the second thing you evaluate is whether they’re competent — which means that it matters if they’re a threat or not. And it seems that touch information helps us make these distinctions, even when it’s irrelevant.”

8) We still don’t really understand how sexual touch works

“We know embarrassingly little about it,” Linden says. “Here’s a very basic question that we can’t fully answer: what makes the genitals different from the rest of the body? Obviously other parts of the body can lead to sexual stimulation, but there’s something special about the genitals. And we just don’t know what it is.”

“If you look at the skin in the genitals, there are some structures — including one called a mucocutaneous end organ — that are present there at higher densities, especially in places like the head of the penis and the clitoris. So it seems likely that it’s involved in sexual sensation. But in truth, we don’t have a way of activating those nerve endings on their own, so we just don’t know.”

“Sexual sensation affects so much in our lives, our social organization, and what makes us human — and we don’t know the biology of it.”

9) Your emotions can warp how you experience pleasure and pain


“The fact that our cognitive state — what we’re thinking about and paying attention to — can modulate our perception of touch is both a blessing and a curse,” Linden says.

“It’s a blessing because it means modulate negative touch through positive experiences, like meditation, exercise, and mindfulness training. But it’s a negative in that if we obsess over pain, we can get into a spiral where we make it worse: you attend to it more, and it feels more painful, and you attend to it more. It also means that if you want to maximize pain to torture someone, you can manipulate their emotional state to make it feel worse. If they feel threatened, or are sleep deprived, or don’t know when pain will arrive, it’s perceived as being worse.”

“This isn’t just true of pain, but of pleasant sensations too. Imagine you’re with your significant other, and he or she caresses your arm — it feels nice. Now imagine you’re in the middle of a heated argument, and you get that exact same caress. The very same nerves will be activated, but it will actually feel different to you — annoying, and unwelcome. That’s because the parts of the brain that are processing emotional touch are affected by the other parts of your brain as well.”

Luke Miller, a cognitive neuroscientist, was toying with a curtain rod in his apartment when he was struck by a strange realization. When he hit an object with the rod, even without looking, he could tell where it was making contact like it was a sensory extension of his body. “That’s kind of weird,” Miller recalls thinking to himself. “So I went , and we played around with it in the lab.”

Sensing touch through tools is not a new concept, though it has not been extensively investigated. In the 17th century, philosopher René Descartes discussed the ability of blind people to sense their surroundings through their walking cane. While scientists have researched tool use extensively, they typically focused on how people move the tools. “They, for the most part, neglected the sensory aspect of tool use,” Miller says.

In a 2018 Nature study, Miller and his colleagues at Claude Bernard Lyon 1 University in France reported that humans are actually quite good at pinpointing where an object comes into contact with a handheld tool using touch alone, as if the object were touching their own skin. A tool is not innervated like our skin, so how does our brain know when and where it is touched? Results in a follow-up study, published in December in Current Biology, reveal that the brain regions involved with sensing touch on the body similarly processes it on the tool. “The tool is being treated like a sensory extension of your body,” Miller says.

In the initial experiment, the researchers asked 16 right-handed subjects to determine where they felt touches on a one-meter-long wooden rod. In a total of 400 trials, each subject compared the locations of two touches made on the rod: If they were felt in different locations, participants did not respond. If they were in the same location, the people in the study tapped a foot pedal to indicate whether the touches were close or far from their hand. Even without any experience with the rod or feedback on their performance, the participants were, on average, 96 percent accurate.

During the experiment, researchers recorded subjects’ cortical brain activity using scalp electrodes and found that the cortex rapidly processed where the tool was touched. In trials in which the rod was touched in the same location twice in a row, there was a marked suppression of neural responses in brain areas previously shown to identify touch on the body, including the primary somatosensory (touch) cortex and the posterior parietal cortex.

There is evidence that when the sensory brain regions are presented with the same stimulus repeatedly, the responses of the underlying neural population gets suppressed. This repetition suppression can be measured and used as a “time stamp” to signify when a stimulus is extracted in the brain.

When the team tested some of the same subjects with touches on their arm instead of the rod, it observed similar repetition suppression in the same brain regions on similar time scales. The somatosensory cortex was suppressed in 52 milliseconds (about one twentieth of a second) after contact on both the rod and the arm. At 80 milliseconds, that activity suppression spread throughout the posterior parietal cortex. These results indicate the neural mechanisms for detecting touch location on tools “are remarkably similar to what happens to localize touch on your own body,” says Alessandro Farnè, a neuroscientist at the Lyon Neuroscience Research Center in France and senior author of both studies.

Interestingly, after each contact, the rod vibrates for about 100 milliseconds, Miller says. “So by the time the rod is done vibrating in the hand, you’ve already extracted the location dozens of milliseconds before that,” he adds. The vibrations on the rod are detected by touch sensors embedded in our skin called Pacinian receptors, which then relays neural signals up to the somatosensory cortex. Computer simulations of Pacinian activity in the hand showed that information about rod contact location could be extracted efficiently within 20 milliseconds.

The vibrations on the rod may provide the key information needed for touch localization. Repeating the same rod experiment, the researchers tested a patient who lost proprioception in her right arm, meaning she could not sense the limb’s location in space. She could still sense superficial touch, however, and she was able to localize where the rod was touched when held in both hands and had similar brain activity as the healthy patients during the task. That finding “suggests quite convincingly that vibration conveyed through the touch, which is spared in the patient, is sufficient for the brain to locate touches on the rod,” Farnè says.

Taken together, these results indicate that people could locate touches on a tool quickly and efficiently using the same neural processes for detecting touch on the body. While Farnè emphasizes that no one in the studies thought the tool had “become part of their own body,” he says the work indicates the subjects experienced sensory embodiment, “in which the brain repurposes strategies for dealing with objects by reusing what it knows about the body.”

“This is really beautiful, comprehensive and thoughtful work,” says Scott Frey, a cognitive neuroscientist researching neuroprosthetics at the University of Missouri. Frey, who was not involved with the studies, believes that the results could help inform the design of better prostheses because it suggests that “insensate objects can become, potentially, ways of detecting information from the world and relaying it toward the somatosensory systems,” he says. “And that’s not something that I think people in the world of prosthetics design really thought about. But maybe this suggests that they should. And that’s kind of a neat, novel idea that could come out of it.”

Benefits of human touch

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