Chapter 5: Drive Theory

First coined by Woodworth (1918). Drive was seen as a force within the individual that activates or energizes behavior. Drive was seen as the reason WHY behavior occurs.

We compared the similarities (both hypothesize an internal source of "energy") and differences between drive theory (influenced by homeostatic view) and ethological theory (emphasis on FAPs and the adaptive function of behavior).

Drive is inferred from behavior. In most cases it is presumed to be activated by a need (e.g., "hunger drive") but may occur in the absence of a need (e.g., sex drive).

Critics of drive theory argue that drive theory suffers from the nominal fallacy, invoking the drive concept is useful to describe behavior but not useful to explain the true causes of behavior.

Two examples of "Drive" Theories (Compare and Contrast these two approaches)

  1. Freud (Non-experimental, based on case studies)

Although he did not use the term "drive" (he referred to "psychic energy" instead) Freud is one of the first to develop a "drive " theory.

Some of the points in his theory are:

    1. Psychic energy builds up when a need exists
    2. There are different types " psychic energy" (e.g., libido, eros, thanatos)
    3. Psychic energy must be channeled to satisfy the need
    4. Society plays a role in determining the appropriate ways to channel psychic energy
    5. The accumulation of psychic energy with no opportunities for channeling is aversive
    6. Reducing psychic energy is pleasurable

We then discussed examples of defense mechanisms. Defenses against unchanneled energy (which is aversive) include reversal, repression, and rationalization)

Criticisms of Freud’s theory

    1. Empirically weak (not based on experimentation)
    2. Not falsifiable (unable to make predictions that can be potentially shown to be false) therefore not testable.
    3. Primarily "post hoc " – explains after the fact

B. Hull’s theory (experimental, empirically based)

    1. Based on the experimental method and heavily influenced by behaviorism. The experimental strategy essentially is to 1) manipulate a need (e.g., food deprivation), 2) observe a change in behavior ; and 3) infer drive level. Example of early studies was the Columbia Obstruction box which was used to measure and compare the strength of different drives. What was the problem with this research?
    2. Used Thorndike’s mechanistic (S-R) "Law of Effect" to explain learning. The law of effect states that learning is due to the mechanical strengthening of responses (R ). These strengthened responses can be elicited by stimuli (S) in the environement. Therefore learned behavior is viewed as a habit – stimuli automatically eliciting responses.
    3. Hull developed a mathematical theory to describe the causes of behavior

sEr     =   D     x      sHr     x      K

Strength of Observable Behavior = Drive x Learning x Incentive Value

 

We examined several predictions of Hull’s theory, some of which were:

    1. Learned behavior (reinforcement) is due to Drive Reduction; without drive reduction learning will not occur.
    2. There is only one type of drive (one "pool" of drive) that serves only to activate oe energize behavior. He referred to this "pool" as a generalized drive. Therefore he predicted that drives can be substituted, hunger can substitute for thirst.
    3. Behavior is directed through learning- stimuli in the environment control and therefore direct responses.

Tests of Hull’s Theory (study the experiments that led to the evidence listed below)

    1. Evidence against the requirement that drive reduction is needed for learning to occur.
    2. Evidence showing learning due to drive Induction
    3. Evidence against the concept of "generalized drive"

Although Hull’s theory was proven wrong, it is considered a successful theory because:

    1. It demonstrated how to systematically test ideas about complex constructs like drive and learning.
    2. It generated an enormous amount of experimentation because the theory made specific predictions that were falsifiable (that is, testable). These experiments led to many advances in several areas of psychology.

Hull’s theory failed partly because research made it clear that not all motivation is caused by homeostatic regulation. Drive reduction is not the only cause of learning. As we discussed earlier in the semester many causes of behavior come from outside stimuli (nonhomeostatic factors), this is especially true for learned behavior.