Abstract: | Using the model of feeding motor conditioned reflex, polymorphism for the rate of the formation of this response was found in a population of laboratory animals. Selection for high and low rate of the formation of this reflex resulted in significant differences inthis character between two strains already in the second generation. These differences are maintained in subsequent generations. The existing henerogeneity for the rate of the formation of conditioned rsponse in the population is shown to be genetically determined. |