Drive reduction theory of motivation became popular during the 1940s and 1950s as a way to explain behavior, learning and motivation. The theory was created by behaviorist Clark Hull and further developed by his collaborator Kenneth Spence. According to the theory, the reduction of drives is the primary force behind motivation. Hull was one of the first theorists to attempt creating a grand theory designed to explain all behavior.
While the drive-reduction theory of motivation was once a dominant force in psychology, it is largely ignored today. Despite this, it is worthwhile for students to learn more about Hull’s ideas in order to understand the effect his work had on psychology and to see how other theorists responded by proposing their own theories.
An Overview of Hull's Drive Reduction Theory
Clark Hull started developing his theory shortly after he began working at Yale University. He drew on ideas from a number of other thinkers including Charles Darwin, Ivan Pavlov, John. B. Watson and Edward L. Thorndike. He based his theory around the concept of homeostasis, the idea that the body actively works to maintain a certain state of balance or equilibrium. For example, your body regulates its temperature in order to ensure that you do not become too hot or too cold. Hull believed that behavior was one of the ways that an organism maintains this balance.
Based on this idea, Hull suggested that all motivation arises as a result of these biological needs. In his theory, Hull used the term drive to refer to the state of tension or arousal caused by biological or physiological needs. Thirst, hunger and the need for warmth are all examples of drives. A drive creates an unpleasant state; a tension that needs to be reduced.
In order to reduce this state of tension, humans and animals seek out ways to fulfill these biological needs. We get a drink when we are thirsty. We eat when we are hungry. We turn up the thermostat when we are cold. He suggested that humans and animals will then repeat any behavior that reduces these drives.
Hull is considered a neo-behaviorist thinker, but like the other major behaviorists he believed that human behavior could be explained by conditioning and reinforcement.
The reduction of the drive acts as a reinforcement for that behavior. This reinforcement increases the likelihood that the same behavior will occur again in the future when then same need arises.
In order to survive in its environment, an organism must behave in ways that meet these survival needs. "When survival is in jeopardy, the organism is in a state of need (when the biological requirements for survival are not being met) so the organism behaves in a fashion to reduce that need," Hull explained. In a stimulus-response (S-R) relationship, when the stimulus and response are followed by a reduction in the need, it increases the likelihood that the same stimulus will elicit the same response again in the future.Hull's goal was to develop a theory of learning that could be expressed mathematically; to create a "formula" to explain and understand human behavior. The "Mathematico Deductive Theory of Behavior" he developed was as follows:
sEr = V x D x K x J x sHr - sIr - Ir - sOr - sLr
- sEr: Excitatory potential, or the likelihood that an organism will produce a response (r) to a stimulus (s)
- sHr: Habit strength, established by the number of previous conditioning
- D: Drive strength, determined by the amount of biological deprivation
- K: Incentive motivation, or the size or magnitude of the goal
- J: The delay before the organism is allowed to seek reinforcement
- lr: Reactive inhibition, or fatigue
- slr: Conditioned inhibition, caused by previous lack of reinforcement
- sLr: Reaction threshold, the smallest amount of reinforcement that will produce learning
- sOr: Random error
Contemporary Views of Hull’s Drive-Reduction Theory
While Hull's theory was popular during the middle part of the 20th-century, it began to fall out of favor due to a number of reasons. Because of his emphasis on quantifying his variables in such a narrowly defined way, his theory lacks generalizability. However, his emphasis on rigorous experimental techniques and scientific methods did have an important influence in the field of psychology.
One of the biggest problems with Hull's drive reduction theory is that it does not account for how secondary reinforcers reduce drives. Unlike primary drives such as hunger and thirst, secondary reinforcers do nothing to directly reduce physiological and biological needs. Take money, for example. While money does allow you to purchase primary reinforcers, it does nothing in and of itself to reduce drives. Despite this, money still acts as a powerful source of reinforcement.
Another major criticism of the drive reduction theory of learning is that it does not explain why people engage in behaviors that do not reduce drives. For example, people often eat when they’re not hungry or drink when they’re not thirsty. In some cases, people actually participate in activities that increase tension such as sky-diving or bungee jumping. Why would people seek out activities that do nothing to fulfill biological needs and that actually place them in considerable danger? Drive-reduction theory cannot account for such behaviors.
While Hull's theory has largely fallen out of favor in psychology, it is still worthwhile to understand the effect it had on other psychologists of the time and how it helped contribute to later research in psychology. In order to fully understand the theories that came after it, it is important for students to grasp the basics of Hull’s theory. For example, many of the motivational theories that emerged during the 1950s and 1960s were either based on Hull's original theory or were focused on providing alternatives to the drive-reduction theory. One great example is Abraham Maslow's famous hierarchy of needs, which emerged as an alternative to Hull's approach.
Dewey, R. (n.d.). Hull’s theory. Psych Web. Retrieved from http://www.psywww.com/intropsych/ch09_motivation/hulls_theory.html
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Hull, C. L. (1935). The Conflicting Psychologies of Learning: A Way Out. Psychological Review, 42, 491-516.
Schultz, D.P. & Schultz, S.E. (1987). A History of Modern Psychology. Harcourt Brace Jovanovich Publications.