The science of touch and emotion.

If you were told you it was possible to communicate gratitude to someone with a two-second touch, would you believe them?


Get touched.
It’s not ok that this is all that’s available for far too many people right now.

Although the power of speech allows us to add great subtlety and complexity in our messages, psychological researchers have demonstrated that something as complex as gratitude or sympathy can be communicated with a simple touch.

In social species, prosocial emotions are those that promote the well-being of the group. By engaging in acts of trust and cooperation, social groups survive.

A growing number of studies on touch and emotion reveal our deep-seated need for human contact and warmth.

Touch may be the key for communicating prosocial emotions, and for promoting group cohesion and survival.

Dr. Dacher Keltner from the UC Berkeley Department of Psychology and Dr. Matthew Hertenstein (now at DePauw University) have conducted extensive research on how touch communicates emotions.

In their 2006 paper Touch Communicates Distinct Emotion, Keltner and Hertenstein investigated the ability of touch to convey various emotions. Given the importance of cooperation and altruism in social groups, Keltner and his colleagues hypothesized that it should be possible to communicate prosocial emotions through touch alone.

For their study, 212 volunteers between the ages of 18-40 were sorted into pairs called dyads. In each dyad, one person did the touching (the “encoder”) and the other received the touch (the “decoder”).

Research assistants used a survey of coding systems that is routinely used by researchers investigating touch. The types of tactile displays, including tapping, stroking, squeezing, poking, pushing, and tickling, among others, were noted and quantified in terms of frequency, duration, and intensity.

Although 106 different encoders participated in the experiment, they tended to use similar tactile displays to convey emotion.  For example, sympathy was most likely to be communicated with patting or stroking, while anger was most likely communicated with pushing.

One of the more humorous findings of the study was how helpless men and women were at communicating specific emotions to one another. As Dr. Keltner explained in a public lecture, “When women tried to communicate anger to the man he had no idea what she was doing and he got nothing right. And when the man tried to communicate compassion to the woman she got zero right. She had no idea what he was doing.”

The Biology of Touch

Dr. Keltner’s studies on touch and emotion exist within the context of evolutionary theory. Altruism, the selflessness and concern for the well-being of others, was even perceived by Charles Darwin as an adaptive trait and is completely in line with the theory of natural selection he so famously elaborated.

Receptors sensitive to pressure, warmth, and other triggers, cause our bodies to release a rush of oxytocin.

Oxytocin has been studied in monogamous prairie volesin nursing mothersand in human couples where it is thought to be involved with the promotion of associative behaviors such as compassion, and which builds trust between individuals.

A more contemporary context for prosocial behaviors is in competitive sports.  In a 2010 paper published in the journal Emotion, Dr. Keltner’s group correctly predicted better outcomes in the 2008-2009 season for those NBA teams whose athletes touched one another most frequently and in a positive manner (e.g. chest bumping, high-fives, hugs, huddles, etc) early in the season.

Not only does touch foster cooperation within groups, it’s necessary for proper physical and psychological development in infant mammals.

From birth, regular, nurturing touch has been shown to have growth promoting effects in infants. Pups that are separated from their mothers for prolonged periods have stunted growth compared to rats who are not separated from their mothers even though they may be fed the same amount.

In a 2003 paper, Dr. Saul Schanberg and colleagues describe how the “mothering behavior” of female rats (in this case grooming) stimulates the release of prolactin and growth hormone in her pups, both necessary for proper growth.

In addition to having a well-known calming effect on infants, a nurturing touch is critical for proper cognitive development. Studies have shown that babies who are held and touched in a positive way more often also demonstrate lifelong resilience to stress and improved cognition. Elderly patients in nursing homes, particularly widows, may also be missing the warm touch of a loved one.

One study observed that “therapeutic touch” (described as a healing process facilitated by hands) decreased stress-associated cortisol levels, and the frequency of agitated behaviors (such as pacing and vocalizations) in individuals suffering from Alzheimer’s Disease.

Given that many western cultures tend to be more touch averse than other cultures in which a kiss is considered a standard greeting, and given what we now know about the importance of touch to our physical and emotional well-being, perhaps we could apply this knowledge to our lives more often.

Maybe the next time you see a good friend, consider giving them a pat on the back, a friendly handshake, or when in Rome, a kiss on each cheek.


Edited (by Seated Massage) article from The Berkeley Science Review, UC Berkeley.