The most complex unconditioned "reflexes of aim and freedom," discovered by I.P. Pavlov, are compared with the "competence drive" and the "motivation of the resistance to coercion," respectively, described by contemporary ethologists. On the basis of the unconditioned "reflex of purpose," conditioned reflexes were developed in which positive emotions arising in connection with the perfection of a skill, irrespective of its pragmatic significance at a given moment, serve as the reinforcement. The unconditioned "reflex of freedom" is regarded as a phylogenetic precursor of the will, and its acute extinction as the physiological mechanism of hypnosis. It was demonstrated experimentally that the appearance of the state of "animal hypnosis" (immobilization catatonia) in rabbits is accompanied by the predominance of electrical activity and heat production in the right hemisphere, i.e., by symptoms which are found in hypnosis in man.