When reading this, I couldn’t help but be reminded of the 5 Love Languages by Dr. Gary Chapman, one of which is physical touch. The premise of the book is that we each have varying way to express our emotional lives and best portray love. I believe some people are adamant believers in physical expressing their affection, which often includes having a very small personal space sphere and sometimes intruding on others. Others prefer to show their interest and affection in other ways.
There is research that proves children who are shown affection such as being held, hugged, kissed develop a healthier physical and emotional life. I think there is a lot more than social norms of any one culture that reinforces people’s comfort level.
Therefore, social norms aside, I believe it varies a lot more than we think in our culture.
I have friends, guys & girl friends alike that absolutely need a hug before they depart and I have friends who would rather not have anyone touch them. I think I’m in the middle, If I don’t know someone, I feel really uncomfortable sitting extremely close or giving hugs away, but If I have a strong emotional connection i.e. best friend, family, boyfriend, I find it imperative that we are close and hugs are given. I really dislike the stereotype, "I'm a theatre person, I have no space bubble", which I've heard so many times. Despite the fact we often work in confined spaces and are often more 'open' people, I don't think that disregards our spacial preferences. I am claustrophobic, so despite whether or not I love working intimately with other performers, I always personally have to consider that what makes myself & others comfortable.