Some basics

Most of the main communication signals are the same all over the world. When people are happy, they smile; when sad - scowling or scowling. A nod almost everywhere means "yes", that is, confirmation. A nod is actually a head tilt. Apparently, this is a congenital gesture, because those who were born blind behave in the same way. Shaking your head from side to side most often means denial, that is, "no." The child learns this gesture in infancy. When the baby has already received enough milk, he begins to shake his head from side to side, pushing the mother's breast. When a small child is fed, he also shakes his head, rejecting any attempt to feed him with a spoon. Thus, he quickly learns the gesture of denial and disagreement and continues to use it in adult life.

Shaking your head is a signal of denial. Its roots are in its infancy and are associated with the repulsion of the maternal breast.

The evolutionary origin of some gestures can be found out if one delves into the primitive animal past of man. A smile in most carnivores is a threat signal, but primates accompany a smile with non-threatening gestures that demonstrate subordination.
Exposure of teeth and nasal congestion originate from threatening gestures used by other primates. Nasal congestion is used by animals as a warning signal. Thus, the beast informs the enemy that, if necessary, he will not fail to use his teeth and claws for attack or defense. This gesture has been preserved in humans, although, of course, hardly anyone today decides to attack the enemy with his teeth.

See how much the same facial expression! You hardly want to go on a date with such gentlemen.

The swelling of the nostrils increases the flow of oxygen, which allows the body to prepare for a response attack or flight. In the primate world, such a gesture suggests that the beast is preparing to react to an obvious threat. In the world of people, swelling of the nostrils is a signal of anger, irritation, sensation of physical or emotional threat, as well as incorrectness of what is happening.