that require a direct, emotional reaction, then human signals are
symbols that require an indirect, abstract reaction. Although a signal shows that something has happened and what the response might be, it does not require modeling of a situation (event) or programming of an action. In contrast to a simple signal, a symbol presupposes an event model and a response model appropriate for a particular event (cf. Friedman 2019, part 1, p. 24).
As is known, apes are able to learn symbolic language, for example, Amslen or Yerkish (Zorina and Smirnova 2006, pp. 137 ff.). But they cannot learn human language—not only because of the peculiarities of anatomy, but also because their vocal responses are involuntary and purely emotional (Zorina and Smirnova 2006, pp. 103-4). Human symbols, and especially language, evolved from gestures, sounds and other signals exchanged between animals. According to George Mead, vocal gestures were of utmost importance for the emergence of symbols, since they modeled not only the behavior of the addressees, but also that of the authors of stimuli (Mead 1972, pp. 61 ff.). According to Vladimir Friedman’s hypothesis, the stimuli shifted toward symbols when proto-symbols (“demonstrations”) differed both from animals’ immediate actions towards each other and from their emotional reactions that expressed their internal states (Friedman 2019, part 1, p. 59).
Ivan Pavlov called sensations, perceptions and mental representations of the environment the first signaling system that humans have in common with animals, and the word the second system that distinguishes humans. “But words have built up a second system of signaling reality, which is only peculiar to us, being a signal of the primary signals. The numerous stimulations by word have, on the one hand, removed us from reality, a fact we should constantly remember so as not to misinterpret our attitude towards reality. On the other hand, it was nothing other than words which has made us human” (Pavlov 1941, vol. 2, p. 179). Nevertheless, not only a word is a signal of primary signals, but every abstract, symbolic action. Both a word and, for example, a human gesture or instrumental action are types of abstract social action.
(3) The evolution of the material side of activity enlarges the niche that man occupies. From generation to generation, humans expand their