The impulse reduction theory: what it is and what it explains

The impulse reduction theory is a model that became popular in the middle of the last century. and it was conceptualized by Clark Hull to explain how behavior, learning and motivation were related.

According to this theory, what encourages us to repeat a behavior, this is learning, is how effective it is in reducing an internal need such as thirst or hunger. The rationale for this theory is that drive reduction is the main force behind motivation.

Although this theory is somewhat out of date today, it does have the merit of having conceptualized in behavior in very concrete and mathematical terms, which served as a model for other theories later. Let's take a closer look at it.

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What is impulse reduction theory?

The impulse reduction theory is a theory of motivation originally put forward by Clark Hull in 1943 and later developed by his collaborator Kenneth Spence. This model holds that drive reduction is the primary force behind motivation, learning and behavior of an organism and would become the main motivational model of the decade of the 40 and 50.

An impulse or "drive" is defined in this theory as the motivation that arises due to a psychological or physiological need that must be satisfied to recover an optimal state for the organism. It works as an internal stimulus that motivates the individual to activate to satisfy the need that has caused that impulse, reducing it. We would have primary drives that are innate, such as thirst, hunger, and sex, and secondary drives that would be learned through conditioning.

Hull was one of the first theorists to try to create a grand theory that would serve to explain all behavior.. He began developing his theory shortly after starting work at Yale University, drawing inspiration from a large number of great thinkers in the behavioral and biological sciences such as Charles Darwin, Ivan Pavlov, John b. Watson and Edward L. Thorndike.

The drive reduction theory was developed as a hypothetical-deductive system in psychology, which consisted of the postulation of participating variables, that is, very precisely defined terms that could be used using mathematical symbols to represent them. so hull tried to develop a system as scientific as that present in any natural or formal science, an idea taken after reading Isaac Newton and the Greek mathematician Euclid.

Hull was also influenced by the work of Ivan Pavlov, especially taking the principles of conditioning, and from Thorndike he got the idea of ​​the law of effect. In fact, it is from these two great theoretical contributions to behavioral sciences that Hull tries to integrate a new system by creating his theory of impulse reduction.

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homeostasis and learning

Clark Hull based his theory on the concept of homeostasis, that is, the idea that an organism actively works to maintain internal balance. For example, our body constantly regulates its temperature to avoid being too cold or too hot and thus be able to carry out its organic functions properly. Hull thought that behavior was one of many ways for the body to maintain its balance, only more visibly.

Based on this idea, Hull suggested that motivation, that is, moving to do something, is the result of biological needs. In his theory, Hull used the term "drive" or "impulse" to refer to the state of tension or activation caused by physiological and biological needs. These needs, such as thirst, hunger or seeking warmth, drive us to do something. As we are in an unpleasant state, being in tension, our organism is motivated to solve a need or reduce it.

With the intention of returning to a pleasant state, humans, and also animals, look for all kinds of ways to satisfy these biological needs. For example, if we are thirsty we look for something to drink, if we are hungry we look for food and if we are cold we put on more clothes. According to Hull, if the behavior performed works to reduce that impulse, that behavior will be repeated in the future in case the same need arises.

conditioning and reinforcement

Although Clark Hull is considered a scientist belonging to the neobehavioral current, he agrees with most of the behaviorists when considering that human behavior can be explained in terms of conditioning and booster. Based on what he himself raises with his theory, the reduction of impulses acts as a reinforcer of a certain behavior.

The establishment of a new behavior that reduces impulses respects the classical stimulus-response relationship., that is, when a stimulus and a response are followed by reduction of need, this increases the probability that the same stimulus, if it appears in the future, will generate the same answer.

This reinforcement increases the probability that the same behavior will occur again in the future if the same need arises. This makes sense since, for an organism to survive in nature, it must carry out behaviors that effectively meet the needs that may arise, learn them and redo them in case the need arises again, since failure to do so runs the risk of not regaining homeostasis and therefore putting yourself in trouble. danger.

We can understand that an organism is in danger as well as that it is facing a serious and potential danger (p. g., dying of starvation) as simply feeling a need that causes displeasure the longer it goes unresolved (eg. g., moderate thirst). Entering a state of need means that the requirements to survive are not being met. In order to satisfy them the organism behaves in a way that focuses on reducing that need.

Deductive mathematical theory of behavior

As we mentioned, Clark Hull proposed a hypothetical-deductive system to be able to explain behavior, with the intention of developing a system as scientific as that of other sciences such as mathematics and physical. His goal was to develop a theory of learning that could be expressed in mathematical terms., and for this he exposed a formula:

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

Where:

• ser: excitatory potential, or the probability that the organism will make a response (r) to a stimulus (s)
• V: Dynamism of the intensity of the stimulus, meaning that if some stimuli exert great influence on others.
• D: Strength of the impulse, determined by the degree of biological deprivation.
• K: Incentive motivation, or the size or magnitude of the goal.
• J: The delay before the organism is able to seek reinforcers.
• sHr: Strength of habit, established by the degree of influence of previous conditioning.
• slr: Conditioned inhibition caused by the previous lack of reinforcement.
• lr: reactive inhibition or fatigue.
• sor: Random error.
• sLr: Reaction threshold or the smallest amount of reinforcement that will produce learning.

In Hull's paradigm there are three essential elements in any other behavioral theory.. E, this is stimulus, O that is organism and R that is response, being the paradigm E - O - R. O is affected by E and determines R. When trying to explain the functioning of the organism, to which we do not have internal access since it can only be represented as a black box model, if they are known what stimuli have entered (input) and what responses the organism has emitted (output), taking into account the previous formula, it will be possible to explain the behavior and learning of EITHER.

criticism of the theory

The theory of impulse reduction was very popular in the middle of the 20th century, however today it is a bit forgotten and the reasons behind it are numerous. Among these we find the exaggerated emphasis on quantifying all behavioral variables, despite not being possible to know everything that influences human behavior in addition to the fact that the theory lacked generalizability. Similarly, it should be said that Hull's interest in using experimental techniques to approach human behavior has had a great impact and influence on subsequent motivational theories.

However, the main problem with this theory is that cannot explain the importance of secondary reinforcers in reducing drives. Unlike the primary drives, such as thirst or hunger, the secondary ones do not intervene directly in the satisfaction of biological needs. An example of this is money, an element that does not directly quench hunger or thirst but does allow us to obtain reinforcing food and drink that does reduce impulses directly. The need to obtain money acts as a potent source of basic need reinforcers.

Another criticism of the model is that the impulse reduction theory does not explain how people, despite being satiated and finding homeostasis, sometimes do not reduce their behavioral urges. For example, on many occasions, after having eaten and having satisfied our hunger, we continue to eat more and more, which would be unnecessary behavior since the function of eating is to reduce the need for hunger.

Finally there is the fact that many people seek tension voluntarily, that is, break their homeostasis. Parachute jumping, bungee jumping or scuba diving at great depths are behaviors that lead us to be in tension, just the opposite of homeostasis and make our need to be protected and calm very dissatisfied. The theory cannot explain why people commit this type of behavior so contrary to what is instinctive.

Despite the fact that all this has contributed to the fact that Clark Hull's impulse reduction theory is not very current today, it is true that it has helped to promote research in psychology from a more scientific perspective, in addition to being the seed for the development of other theories on human behavior that came after. For example, many motivation theories that emerged during the 1950s and 1960s are based on Hull's theory or had some influence received from it, as is the case of Maslow's pyramid, which emerged as an alternative to the model of Hull.

Bibliographic references:

• Hull, C. L. (1943). Principles of Behavior. New York: Appleton-Century-Crofts.
• Hull, C. L. (1952). Clark L. Hull. A History of Psychology in Autobiography. Worcester, Mass.: Clark University Press.
• Hull, C. L. (1952). A behavior system. New Haven, CT: Yale University Press.
• Campbell, B., & Krealing, D. (1953). response strength as a function of drive level and amount of drive reduction. Journal of Experimental Psychology, 45, 97-101.