a concept expressing the ability of living beings to produce voluntary movements and change under the influence of external or internal stimuli-stimuli; characterization of living beings as the ability to transform the environment or maintain vital ties with the environment. It is a characteristic of the organism’s vital activity – not a balance with the environment, but an active overcoming of the environment, determined by the model of the desired future. Activity is built according to probabilistic forecasting of the development of events in the context of the interaction of the organism with the environment. In psychology, it appears in correlation with activity, being revealed as a dynamic condition for its formation, implementation and modification, as a property of its own movement. Activity reflects the specifics of the subject’s internal states directly at the moment of action (in contrast to reactivity, when actions are conditioned by the previous situation), as well as arbitrariness as the conditionality of activity by the presence of a goal in the subject (in contrast to field behavior, when activity is carried out not as a result of the subject’s own internal needs and motives, but as a result of the features of the external situation that attracted his attention).