Studies of complex forms of behavior in various vertebrates.

In the evolutionary series of vertebrates, a correlation was established between degrees of structural and functional organization of the brain and features of the formation of complex behavioral acts. Gradual evolution of a complex sequence of motor, food-obtaining, conditioned reflexes, and a capacity for visual discrimination in the phylogenetic line of vertebrates (cartilaginous and marine bony fishes, reptiles, and mammals--insectivores, rodents, and primates) was disclosed.