Head

People nod in order to indicate that they agree. It is a common sign all over the world. Sometimes, when you are speaking to your professor, you are nodding in order to show that you understand every word of his. Some scientists stepped forward in distinguishing nodding as the mass event. For example, if all the auditory start nodding, your mirror neurons accept these movements as your own and you start nodding with them. Nevertheless, this sign does not bring any context. It is just general way of repetition.

In the routine life of yours nodding at somebody means that it is his turn to do something or talk. If you are speaking to somebody and nod towards another person, you indicate that you are speaking about him exactly. For example, in some societies it is considered impolite to point with your finger. Nodding is a little bit neutral signs in this case.

Shaking head from side to side means "no". However, in Bulgaria this movement means the opposite. In Greece if you nod slightly and lift your eyebrows, it means "no" too. In many countries nodding is accepted as an everyday greeting.

If you shake your head and make your eyes wide open, it means that you do not believe in what you hear. Along with slight smile it means that a person is amused. If somebody shakes his head and keeps his mouth closed it suggests that he is annoyed.