What Personality Theories in Psychology May Tell You About Yours

• Structuralism was the first school of thought and focused on breaking down mental processes into their most basic elements using techniques such as introspection. Major thinkers are Wilhelm Wundt and Edward Titchener.
• Functionalism formed as a reaction to the theories of structuralism and focused on the role that the mental processes play instead of the mental processes themselves. Thinkers associated with this outlook include John Dewey, James Rowland Angell, and Harvey Carr.

• This school of psychology is based on the idea that we experience things as unified wholes.
• The approach started in the late 19th century in response to the molecular approach of structuralism.
• Instead of breaking down thoughts and behaviour to their smallest parts, the gestalt psychologists believed you should view the whole of experience.

Psychology was not separate from philosophy until the late 1800s.

• During the 17th century, philosopher Rene Descartes introduced the idea of dualism - that the mind and body were two entities that interact to complete the human experience.
• While early philosophers relied on methods such as observation and logic, today's psychologists use scientific methodologies to draw conclusions about human thought and behavior.
• Physiological research on the brain and behavior also contributes to psychology.

• During the mid-1800s, a German physiologist Wilhelm Wundt outlined many of the major connections between the science of physiology and the study of human thought and behavior.
• He viewed psychology as the study of human consciousness and tried to apply experimental methods to study internal mental processes.
• His processes are known as introspection and seen as unreliable and unscientific today, but it helped to set the stage for future experimental methods.
• The opening of his psychology lab In 1879 is considered to be the official start of psychology as a separate scientific discipline.

When Ivan Pavlov and his dogs led to the discovery of learned behaviour through repeated exposure, and Edward Thorndike discovered the Law of Effect that stated that rewarded behaviours tended to increase, many psychologists were impelled to separate psychology from armchair introspection and formulated their theories as mathematical formulas.

• The Drive x Habit Theory. Clark Hull's formula was sEr = D x sHr, which states that excitatory tendency (E) is the result of the drive (D) combined with the habit (H). The drive is nonspecific, such as hunger or thirst. The habit, however, depends on the stimulus (s) and response (r). But the theory turned out to be wrong and even opposite in many cases. 
• Expectation x Value Theory. Drawing on ideas in economics and game theory, Edward Tolman and Kurt Lewis formulated an alternative account by evaluating motivation based on expectations. Tolman expressed the ideas as the mathematical formula: Subjective Expected Utility = Probability1 * Utility1 + P2U2 + P3U3 + … where subjective expected utility of an action equalled the motivation to act. But, if you expect a reward, why act and not simply passively wait for the expected reward? 

Donald Hebb realised that existing theories were too focused on reacting to the immediate environment. Thoughts, ideas and goals could be just as strong for triggering action as sights and sounds.

Together with John Atkinson, they noted that the study of motivation had undergone a "paradigm shift", where motivation couldn't be seen as how actions get started, but how the organism decides to change its behaviour from one thing to another.