In a 1906 address to the American Psychological Association, Mary Whiton Calkins argued that structuralism and functionalism, the two major schools of thought at the time, were "too often opposed to the point of mutual exclusion." This early debate between structuralism and functionalism is just one example of the many differing theoretical outlooks in psychology. Learn more about some of the most influential psychological schools of thought:

• Structuralism vs. Functionalism
• Psychoanalysis
• Behaviorism
• Humanistic Psychology