Laughter, as a physiological feature given to every person, is an indicator of positive emotions and good mood. A person laughs at a joke he hears or the realization that the situation is comical, just as a laugh a person shows a benevolent disposition towards the interlocutor or a desire to get closer to the person. Laughter is one of the means of communication that is understandable to all people and has no speech barrier. Laughter is a complex motor act, consisting of contraction of the muscles of the diaphragm and accompanied by the work of the vocal apparatus. The center of laughter is localized in the brain stem, and the cerebellum, midbrain and hypothalamus are involved in the organization of laughter.

By the time of birth, the child does not know how to laugh, and the only means of communication with the world is for him to cry. He shows his needs to them and satisfies the emerging needs until a certain age.
A newborn baby can smile, but this happens involuntarily. The smile of a newborn is not a positive emotion, but a spontaneous contraction of the facial nerves, as a result of the formation and development of the nervous system. Only a peaceful environment, a sense of comfort and security can contribute to the further development of pleasant sensations. Consciously, the child begins to smile by the age of two months, he copies his mother’s smile and thus expresses his pleasure.