John B. Watson presents the basis of behavioral psychology.
John B. Watson, "Psychology as the behaviorist views it," Psychological Review 20, no. 2 (1913): 158–177
PSYCHOLOGY AS THE BEHAVIORIST VIEWS IT
BY JOHN B. WATSON
The John Hopkins University
Psychology as the behaviorist views it is a purely objective experimental branch of natural science. Its theoretical goal is the prediction and control of behavior. Introspection forms no essential part of its methods, nor is the scientific value of its data dependent upon the readiness with which they lend themselves to interpretation in terms of consciousness. The behaviorist, in his efforts to get a unitary scheme of animal response, recognizes no dividing line between man and brute. The behavior of man, with all of its refinement and complexity, forms only a part of the behaviorist's total scheme of investigation.