1878 - 1958
John Watson is considered the father of behaviorism due to his opposition to the mainstream psychological view of the unconscious and psychoanalytic thought. To the behaviorist, the outward expression of the self is all that can be measured and therefore the only variable worthy of exploration.
His lecture at Columbia University entitled 'Psychology as the Behaviorist Views It' has become the manifesto for behavioral psychologists such as B.F. Skinner. His opposition to psychoanalytic theory split the field of psychology into two distinct and almost always oppositional schools of thought.