In America, the comfortable distance or social defined distance can be summarized in four types: intimate distance, personal distance, social distance and public distance. Intimate distance ranges from direct physical contact to a distance of about 45 centimeters. Personal distance is about 45-80 centimeters and is most common when friends, acquaintances and relatives get together. Social distance is about 1.3-3 centimeters and people in social gatherings often keep larger distance. Most people from America will feel uncomfortable when others are too close to them except for expressing affection. And being too far from them will also be strange. However, in China, people often don’t pay much attention to distance between each other.
中美非言语交际中的文化差异(3):http://www.youerw.com/yingyu/lunwen_75516.html