Touch plays an important role in our ability to form and maintain relationships with others, but touching the wrong person in the wrong place can have awkward and sometimes even aggressive consequences. Thankfully, a team of experts looked into the matter and recently created a chart of “safe” and “taboo” body zones, so you know whether or not to go in for a hug, or just stick with a handshake.

Researchers at Oxford University in the UK and Aalto University in Finland conducted the largest study ever on physical contact in humans and found that culture and gender play a large role in an individual’s concept of personal space. For the study, the researchers polled over 1,300 men and women in five different European countries (Great Britain, Finland, France, Italy, and Russia) on who they felt comfortable being touched by and where. The replies were gathered using an Internet poll, and most of the respondents were described as both relatively young and well educated. The result of this plethora of data is the “touch map” — a diagram which indicates how appropriate it is to touch other people’s body parts based on your personal relationship with them.

When in doubt, just shake hands. PNAS

According to the researchers, the body zones on the touch map are largely related to pleasure. "The greater the pleasure caused by touching a specific area of the body, the more selectively we allow others to touch it," said study researcher Juulia Suvilehto in a statement.

Many of the results coincide with common beliefs. For example, the polls revealed no one liked to be touched in their genitals by anyone other than their romantic partner, and it was generally frowned upon to be touched anywhere other than the hands by someone who was not a close friend or family member. In addition, both sexes revealed that they were more comfortable being touched by their mothers and aunts than they were their fathers and uncles. Also, both sexes revealed that the individual they felt least comfortable being touched by was a male stranger.

The result also revealed other more interesting glimpses into human social interaction. For example, it seemed that, when it comes to touching, blood is not always thicker than water. The majority of respondents felt more comfortable being touched by their friends than they did by family members. In addition, once established, our willingness to be touched by an individual does not fade over time.

“It is the relationship rather than familiarity that matters,” Professor Robin Dunbar, an Oxford researcher who was involved in this study, explained in a statement. “A friend we haven’t seen for some time will still be able to touch areas where an acquaintance we see every day would not.”

The study also revealed cultural differences between respondents' responses to touch. For example, the British proved to be the least comfortable with touching, while the Finnish respondents were the most comfortable with physical close contact. The results are interested, and show that despite the advance of technological interactions, humans still use touch as an extension of the personal bonds between individuals.

“Touch is universal,” Dunbar said. “While culture does modulate how we experience it, generally we all respond to touching in the same ways.”

Source: Suvilehto JT, Glerean, Dunbar RIM, Hari R, Nummenmaa L. Topography of social touching depends on emotional bonds between humans. PNAS. 2015.