Generally the closer the relationship, the fewer areas of the body were deemed taboo. Photo / iStock
If you struggle to know when it is appropriate to give someone a hug or even simply pat them on the arm, help is at hand.
Oxford University scientists have created a series of body maps that show just where we are comfortable to be touched.
The "touchability index" provides colour-coded information for everyone from our nearest and dearest to extended family, casual acquaintances and complete strangers.
It also showed - again, unsurprisingly - that the less we know someone, the less comfortable we are to be touched by them. However, there was one noticeable exception.
Men, it seems, have no areas which would be completely off limits to a touch from a total stranger - as long as the stranger is a woman.
Working with Finnish scientists, Oxford University psychologist Professor Robin Dunbar set out to investigate where we are comfortable to be touched and just how much the answer depends on who is doing the touching.
Almost 1500 men and women from Britain, Finland, France, Italy and Russia were given a series of outlines of the human body and asked to colour in which parts they would allow someone to touch, front and back. Each person created touchability maps for 13 members of their social network, including their partner, their parents, their siblings, aunts, uncles, cousins and acquaintances.
They also coloured in two more shapes, one for a stranger of each sex.
In general the closer the relationship, the fewer areas of the body that were taboo, although people tended to be uncomfortable about letting anyone except their nearest and dearest touch their erogenous zones.
This meant that while a woman might be happy for her uncle to stroke her back, her front would be off limits. And male strangers should note that almost all parts of the female body are to be avoided, other than the hands.
Interestingly, the men studied had a different viewpoint.
They didn't want another man touching them, with even the head and the feet no-go zones.
However, almost the entire male body was up for grabs to a female stranger or acquaintance, with no part considered taboo.
In fact, for men, a woman they barely know has similar "touching rights" to a parent and more than a brother or sister, the journal Proceedings of the Royal Academy of Sciences reports. Although the reason for this is not clear, the study did find that the more pleasurable a touch was believed to be, the larger the body area that person was allowed access to.
Despite their tactile reputation, the Italians were only slightly more comfortable with touching than the British. The Finns were the most relaxed about being touched.
However, the differences were small and the results were broadly similar across all the countries studied.
Professor Dunbar, a leading evolutionary psychologist, said touch helps maintain relationships by triggering the release of endorphins, the feel-good brain chemicals usually associated with exercise.
He said: "Touch is universal. While culture does modulate how we experience it, generally we all respond to touching in the same way.