Watson thinks that the formula of behavior occurrence is stimulus-response. Response can be predicted from stimulus, and stimulus can be inferred from response. In Watson's view, stimulation refers to the changes in the objective environment and internal organization itself, and reaction refers to the movement of the whole body, the activities of the arms, legs and trunk, or the joint movement of all these moving organs.

He equated psychological activities such as thinking, emotion and personality with a series of actions. Because stimulus exists objectively and is not determined by heredity, and behavior response is caused by stimulus, so behavior cannot be determined by heredity.

(B) one-sided exaggeration of the role of environment and education

There is no denying that Watson's environmental determinism is indeed enlightening, which makes people pay attention to the social factors of individual psychological development. At the same time, in real life, we also deeply understand the great role of environment, including family environment, social environment and school education environment in individual development.