Clark L. Hull: Biography, Theory And Contributions
Clark L. Hull was a renowned American psychologist who lived between 1884 and 1952 and he was president of the American Psychological Association between 1935 and 1936. This author has gone down in history mainly for his theory of impulse reduction, but this was not his only contribution to psychology and other related sciences.
In this article we will review the biography of Clark L. Hull and his theory of impulse reduction. We will also analyze the influence of this profoundly relevant theorist in the development of behaviorism, and therefore of scientific psychology.
Clark Leonard Hull was born in Akron, a town in the state of New York, in 1884. As he relates in his autobiography, his father was an aggressive and uncultivated man who had a farm. Hull and his younger brother worked there during their childhood, often skipping school to help in the family business.
At 17, Hull began working as a teacher in a rural school, but shortly after he decided that he wanted to study more, so he entered a high school and later the University of Alma, Michigan. Shortly before graduating he nearly died from typhoid fever.
He later moved to Minnesota to work as an apprentice mining engineer, having specialized in mathematics, physics, and chemistry. However, he contracted polio; Due to this disease he lost the ability to move in one leg. During the recovery period Hull began reading psychology books.
After the illness he returned to work as a teacher and married Bertha Iutzi. He and his wife began attending the University of Michigan, where Hull graduated in Psychology in 1913 After working for a few years as a professor at the University of Wisconsin he obtained a position at Yale University, where he worked until his death in 1952.
Main contributions to behaviorism
Hull considered that psychology is a full-fledged natural science, like physics, chemistry or biology As such, its laws could be formulated through numerical equations, and secondary laws would exist to explain complex behaviors and even individuals themselves.
Thus, this author sought to determine the scientific laws that explain behavior, and in particular two complex and central aspects of human behavior: learning and motivation. Other theorists, such as Neal E. Miller and John Dollard, worked in the same direction as Hull to find the basic rules that would predict behavior.
On the other hand, Hull was the first author to study the phenomena of suggestion and hypnosis using quantitative experimental methodology. In 1933 he published the book “Hypnosis and Suggestibility”, for which he researched for about 10 years. He considered these methods to be fundamental to the deep understanding of psychology.
Hull proposed in his book “Principles of Behavior” (1943) the theory of impulse, “drive” in the original English. This work had a fundamental influence on psychology, sociology and anthropology in the 1940s and 1950s, and remains one of the classic reference theories in the history of behaviorism and psychology in general.
Until Hull’s arrival, no psychologist had translated the concepts of learning (particularly reinforcement and motivation) using mathematics. This contributed to the quantification of psychology and consequently to its approach to other natural sciences.
The theory of impulse reduction
Hull proposed that learning is a way of adapting to the challenges of the environment that favors the survival of living beings. He defines it as an active process of forming habits that allow us to reduce impulses, such as hunger, fun, relaxation or sexuality. These can be basic or acquired through conditioning.
According to Hull, when we are in a “state of need” the drive, or motivation, increases to carry out a behavior that we know from experience satisfies the need. For the behavior to be executed, it is necessary that the habit have a certain strength and that the reinforcement that will be obtained from the behavior motivates the subject
The formula that Hull created to explain motivation is as follows: Behavioral Potential = Habit Strength (number of reinforcements obtained so far) x Drive (need deprivation time) x Incentive value of reinforcement.
However, Hull’s theory was defeated by the propositional behaviorism of Edward C. Tolman, which had greater success because of the introduction of cognitive variables (expectations) and demonstrated that learning can occur without the need for reinforcement. This fact called into question the basis of Hull’s approaches.
