Did you know that all human beings have a 'comfort zone' regulating the distance they stand from someone when they talk? This distance varies in interesting ways among people of different cultures. Greeks, others of the Eastern Mediterranean, and many of those from South America normally stand quite close together when they talk, often moving their faces even closer as they warm up in a conversation. North Americans find this awkward and often back away a few inches. Studies have found that they tend to feel most comfortable at about 21 inches apart. In much of Asia and Africa, there is even more space between two speakers in conversation. This greater space subtly lends an air of dignity and respect. This matter of space is nearly always unconscious, but it is interesting to observe. This difference applies also to the closeness with which people sit together, the extent to which they lean over one another in conversation, how they move as they argue or make an emphatic(强调的)point. In the United States, for example, people try to keep their bodies apart even in a crowed elevator in Pads they take it as it comes! Although North Americans have a relatively wide 'comfort zone' for talking, they communicate a great deal with their hands—not only with gesture but also with touch. They put a sympathetic hand on a person's shoulder to demonstrate warmth of feeling or an arm around him in sympathy they nudge (用肘轻碰)a man in the ribs to emphasize a funny story they pat an arm in reassurance or stroke a child's head in affection they readily take someone's arm to help him across a street or direct him along an unfamiliar route. To many people— especially those from Asia or the Moslem countries—such bodily contact is unwelcome, especially if inadvertently(不经意地)done with the left hand. A suitable title for this passage would be ______.