Clark L. Hull

Born in New York in 1884, Clark L. Hull originally set out to be an engineer.

His pursuits in higher education took a turn, however, when he came across the works of John B. Watson and Ivan Pavlov.

The basis of the theory is that all motivation is a result of biological or physiological needs like hunger, thirst and the need to find and sustain warmth.

Drive reduction theory is a partial extension of the concept of homeostasis in biology.

In 1918, he was awarded his Ph.D and ten years later his book Aptitude Testing was published.

Hull was a behaviorist, meaning that he believed that all behavior could be explained by certain principals of conditioning. Out of this foundation, Hull would develop his drive theory of behavior.

The theory explained that humans are driven by these needs and will participate in behaviors that reduce them; and that reduction of need acts as a reinforcement for behavior.

When behaviors are positively reinforced, behaviorist theorize that it's more likely that those behaviors will be repeated.

Hypnosis and Suggestibility was published in 1933. Hull was on of the first psychologists to empirically study hypnosis.

Mathematico-Deductive Theory of Rote Learning published in 1940, in which he first presents his theories of learning.

Principles of Behavior published in 1943

Hull comprised a mathematical equation for his theory of behavior.

sEr = V x D x K x J x sHr - sIr - Ir - sOr - sLr

Behaviorism differs from most other schools of modern psychology because it doesn't look to the mind for answers; but to the conditioning of an individual.

Immaterial factors like abstract thought and the unconscious part of the mind do not play a role, as far as behaviorists are concerned.

One of the most commonly adopted aspects of behaviorism is the idea of a 'time-out'.

When a child does something wrong, they are punished by being sent to 'time-out', usually isolated from others and ignored for a set amount of time. The idea is that the child will learn that certain behaviors will result in a certain undesirable outcome, and eventually they'll start to avoid those behaviors.

Systematic desensitization is another product of behaviorist theories.

Patients with certain phobias can (in a controlled and safe environment) become desensitized to their fear(s). Patients are asked to rank their level of fear to certain levels of exposure to their phobia and then are taught cognitive coping mechanisms to aid in calming anxiety. They are subject to gradual exposure, in a state of deep relaxation each time, and may become desensitized to their phobia altogether.

This works, according to behaviorists, because the patients are being conditioned to have a neutral response, as opposed to a negative one.