Traditional Learning Theories Chapter 2

Traditional Learning Theories Two major theoretical approaches S-R (stimulus-response) theories state that learning occurs through the association of environmental stimuli S-S (stimulus-stimulus) theories state that learning involves recognizing when important events are likely to occur and understanding how to obtain these events Anti-theoretical (methodological)

S-R versus S-S Theories S-R theorists (Behaviorist) inflexible view of behavior stimulus environment controls behavior very machine-like S-S theorists (Cognitive) somewhat flexible internal processes control behavior learn relationships which guides behavior

Types of S-R theories Reinforcement is necessary to learn an S-R association (Reinforcement) Thorndike’s law-of-effect proposed that reinforcement was a necessity Also, Hull’s S-R theory of learning was the culmination of this line of thinking Reinforcement is not necessary to learn an S-R association (Contiguity) Guthrie

Hull’s Reinforcement Theory Proposed that primary drives (e.g., hunger, thirst) are produced by states of deprivation We have biological needs and corresponding psychological drives we have a biological need for water that is accompanied by a psychological drive called thirst

Theorized that drive motivates behavior Drive reduction restores homeostasis By restoring homeostasis, drive reduction leads to S-R associative learning

Excitatory potential reflects the likelihood that a specific event (S) will cause the occurrence of a specific behavior (R). SER (S) (R)

Hull believed that the intensity of instrumental activity is determined by the combined influence of several factors Drive (D), e.g., vampire thirst Incentive (K), e.g., amount of blood reward Habit strength (H), # of previously rewarded lever- presses Inhibition (I), # of previously unrewarded rewarded lever-presses

Hull’s Formula: SHR SIR SER = drive (D) * incentive (K) * habit (H) – inhibition (I) SHR SIR

Excitatory potential is determined by: Drive (D), the internal arousal state produced by deprivation (appetitive) or stimulation (aversive) , or stimuli associated with deprivation or stimulation. Incentive motivation (K), the internal arousal produced by the reinforcer (e.g., it’s magnitude) Habit strength (H), the strength of the connection between the stimulus and response. Inhibition (I), suppression caused by previous responses failing to produce reward.

Sources of Drive Events that threaten survival activate the internal drive states sex partner predator Some events that do not threaten survival may also activate the drive state Highly desirable stimuli, like saccharin, activate drive states It tastes good but has no caloric value Highly aversive stimuli, like mild footshock, activate drive states Mild footshock is aversive, but it does not threaten survival

Innate Habits Habit strength can be Innate: (SUR) or Acquired through experience (SHR) Habit strength increases each time a response produces drive reduction

Elimination of Behavior Unsuccessful behavior causes a drive to persist. If drive persists, all behavior inhibited. Reactive inhibition IR: the temporary inhibition of behavior due to the persistence of a drive state after unsuccessful behavior Conditioned inhibition SIR: the permanent inhibition of a specific behavior as a result of the continued failure of that response to reduce the drive state.

Evaluation of Drive Theory Many of Hull’s ideas do accurately reflect important aspects of human behavior: Intense arousal can reinforce behavior Environmental stimuli can develop the ability to produce arousal, thereby motivating behavior (lead to Spence’s work on acquired drives) Failure to distinguish learning and performance

Acquired Drives Acquired drive: an internal drive state produced when an environmental stimulus is paired with an unconditioned source of drive This system works through classical conditioning Spence, one of Hull’s students, developed this approach

Guthrie’s Contiguity Theory Guthrie proposed that contiguity, not drive reduction, was sufficient to establish an S-R connection. He believed that learning is a simple process governed entirely by contiguity Getting the response to occur (however this is done) in the situation was all that mattered The last response to occur in the situation will be reproduced the next time

The impact of Reward Guthrie believed the last thing done in the old situation before the situation changed strengthened the S-R bond. He believed that “stimulus change” produced learning. Rewards produce stimulus change

The Impact of Punishment If the response terminates the punishment, the response will become conditioned to the stimulus context in which the punishment occurred. Guthrie believed that punishment will eliminates ongoing behavior only if response elicited by punishment is incompatible with the inappropriate response. e.g., spanking produces responses incompatible with most other responses

The Importance of Practice Guthrie proposed that learning is not gradual but occurs in a single trial. The strength of an S-R association is at maximum value after a single pairing of the stimulus and response.

Performance gradually improves: 1) Subjects attend to only some of the stimuli present during conditioning trials. 2) Many stimuli have to become conditioned to produce a particular response. 3) All behavior are complex are consists of many separate responses. For the behavior to be efficient, each response element must be conditioned.

Breaking Up a Habit Guthrie believed that old habits could not be “forgotten”, but could only be replaced by a new habit

Three methods of breaking habits 1) Fatigue method: The eliciting stimulus is presented so often that the person is so fatigued that the old habit cannot be performed. At that point, a new response will occur and a new S-R association will be learned, or no response will occur. 2) Threshold method: the stimulus is presented at a level below threshold for eliciting the response. The intensity of the stimulus is gradually increased. 3) Incompatible method: person is placed in a situation where the new habit replaces the old (Overcorrection)

Valuable Ideas 1) Punishment sometimes intensifies an inappropriate behavior when it elicits a behavior that is compatible with the punished response. 2) Contiguity between a response and reward is critical to prevent acquisition of competing associations. 3) Only a portion of the environmental stimuli are active at a given time.

Bad Ideas 1) Some actions are not reproduced even though substantial stimulus change followed the action. 2) Reward predicts responses better than either frequency or recency (last response). 3) All learning is not single trial learning.

Tolman’s Purposive Behavior When Tolman proposed his cognitive theory in the 1930s and 1940s, most psychologists preferred Hull’s mechanistic theory. By the 1950s, the cognitive view started to gain supporters.

Flexibility of Behavior Tolman proposed that behavior has both direction and purpose. He believed that behavior is goal oriented. We are motivated either to achieve a desired condition or to avoid an aversive situation. He stated that certain events in the environment convey information about where our goals are located. We can reach our goals only after we learn to read the signs leading to reward or punishment.

Learning or Performance?

Learning versus Performance

Is Reward Necessary for Learning? Experience of two events is sufficient for learning (S-S) Reward effects performance, not learning The understanding of when events will occur can develop without a reward. Presence of reward will motivate the organism to exhibit previously learned behavior.

Evaluation of Purposive Behavior Tolman’s work caused Hull to make changes in drive theory. Once the ideas were incorporated into drive theory, Tolman’s work did not have a big impact on learning theory. When drive theory developed problems in the 60s and 70s, cognitive approach gained wider approval

Skinner’s Methodological View Skinner argued that the goal of behaviorism should be to identify and isolate the environmental factors that govern behavior. He believed the goal of psychology was to predict and control behavior Ability to do so depends on understanding the circumstances that govern the occurrence of the behavior

“Some Boxes”

The Importance of the Environment Most of Skinner’s research focused on the role of reinforcement. Reinforcer: an event whose occurrence increases the frequency of the behavior that preceded the event. Operant response: the behavior that controls the rate at which specific consequences occur. Skinner’s work led to the development of Behavior Modification for treating behavior pathology.

The Role of Theory? Skinner argued that the use of “hypothetical constructs” does not contribute to our understanding of behavior. Many psychologists do not agree with Skinner’s atheoretical approach. They say that theory guides research and leads to new findings and uses for information.