The results obtained in the framework of six informational models of perception prove the preference of encoding of input information by three-graded features, the preference of using of three-parameter mechanisms and reliable fixation of periodic events which are repeated three times. In the latter case the excess of chance threshold and fixation of regularity by means of positive emotions play an important role. Deduced ternarity dominates in the unconscious, it is revealed primarily in phenomena of culture (colour triads in national schools of painting, three stage structure of literature texts, religious, philosophical, language and other systems) as well as in three-factorial structure of semantic space and three-dimensionality of the perceived world.