He is considered one of the fathers of functional psychology

One of the interesting facts about John Dewey is that he is considered one of the fathers of functional psychology. Dewey's first two books, Psychology (1887) and Leibniz's New Essays Concerning the Human Understanding (1888), were both published at the University of Michigan, and both expressed Dewey's early dedication to British neo-Hegelianism. Dewey attempted a synthesis of idealism and experimental science in Psychology.

While still a professor of philosophy at Michigan, Dewey and his junior colleagues, James Hayden Tufts and George Herbert Mead, as well as his student James Rowland Angell, were all heavily influenced by William James' Principles of Psychology (1890) and began to reformulate psychology, emphasizing the social environment on the activity of mind and behavior rather than the physiological psychology of Wilhelm Wundt and his followers.

Their new approach to psychology, subsequently named functional psychology, emphasized activity and application. Dewey argues against the traditional stimulus-response understanding of the reflex arc in his article "The Reflex Arc Concept in Psychology," which appeared in Psychological Review in 1896, in favor of a "circular" account in which what serves as "stimulus" and what as "response" depends on how one considers the situation and defends the unitary nature of the sensory-motor circuit. While he does not reject the existence of stimulus, sensation, and reaction, he disagrees that they are distinct, juxtaposed events that occur as if they were links in a chain. He proposed that there is coordination in which the stimulation is enhanced by the outcomes of prior encounters.