My mother always told me that there are things that you just don't do. For example, horsing around in Church, being loud and yelling at the table or in public, picking your nose, etc. While your mother may have simply called this "behaving," sociologists call these things social norms. Social norms are defined as "the implicit or explicit rules a group has for the acceptable behaviors, values, and beliefs of its members." In layman's terms, social norms are like an everyday code of conduct that determines how you behave in certain situations.
Social norms are often very strictly enforced and offenders are often ostracized or outright rebuked for their conduct. Also, such norms are more rigorously held to in certain situations than in others. For example, it is a social norm that people should be decently covered in public, but a woman wearing a swimsuit and shorts into McDonald's is less likely to be ostracized than a woman wearing the same outfit in a Church service or at a funeral. Since, depending upon your personality, violating minor social norms can be fun, and since I was required to do it, I decided to violate the norm of personal space and see what came of it.
America is an individualistic culture and as a result, personal space is so revered, it is almost a religion in itself. All of this means that Americans take violations of that space quite seriously. I set out to test this hypothesis by experimenting with interpersonal space violations in different situations. I engaged in several abnormal behaviors such as sitting next to someone on a nearly empty bus, coming into a public restroom and standing next to another person, rather than a few stalls down, and finally, talking to people face to face from very short distance.
The reactions I received varied in their nature and in their strength, but in all cases there was at least some response. The mildest response came from those incidents where I stood very close to someone while talking to them.