Why do the same gestures mean different things in different cultures?

The answer

Gestures are among the most culturally variable forms of human communication. The thumbs-up, positive in most Western cultures, is offensive in parts of the Middle East, West Africa, and South America, roughly equivalent to the middle finger. The 'OK' hand sign means 'zero' or 'worthless' in France, money in Japan, and is an insult in Brazil and Turkey. Beckoning with the index finger is considered rude across much of Asia, where an open hand with fingers waving downward is preferred. In Bulgaria and parts of India, nodding the head means 'no' and shaking it means 'yes,' the opposite of most other cultures. Even pointing varies: many Indigenous cultures point with their lips rather than their fingers. These differences are a common source of international misunderstandings.