PSY 402
Theories of Learning
Chapter 7 – Behavior & Its Consequences
Instrumental & Operant Learning

 Reinforcement Theory
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Thorndike’s “Law of Effect” for cats in the puzzle box.
 Skinner boxes – rats pressing bars
 Contiguity Theory
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Guthrie – association is enough
Estes – Stimulus Sampling Theory

 Guthrie proposed that no reinforcement was needed – just contiguity (closeness) in time and place.
 If learning is immediate and one-trial, why are learning curves gradual?
 Only a few stimulus elements are associated on each trial, but more build up with each trial.
 His view was wrong but influential (Estes).

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The reinforcer is salient, so it changes the stimulus (environmental situation).
Reward keeps competing responses from being associated with the initial stimulus.
 Competing responses are instead associated with the presence of the reward.
Fixity of cat flank-rubbing supported Guthrie but was later shown to be related to the presence of the experimenter instead.

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His theories relied on “intervening variables” not mechanistic S-R associations.
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Behavior is motivated by goals.
Behavior is flexible, a means to an end.
 Rats in mazes form cognitive maps of their environment.
 Animals learn about stimuli, not just behavior.

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Changing the maze layout resulted in running toward the same “goal.”
 A light could have been used as a cue in both situations.
Using a “plus maze,” some rats were trained to always turn a certain direction, while others were trained to reach a consistent place.
 The consistent place was easier to learn.

 Rats were given experience in a complex maze, without reward.
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Later they were rewarded for finding the goal box.
Performance (number of errors) improved greatly with reward, even among previously unrewarded rats.
 Reward motivates performance, not learning.

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Skinner was uninterested in theory – he wanted to see how learning works in practice.
Operant chambers permit behaviors to be repeated as often as desired – more voluntary.
Superstitious behavior
– animals were rewarded at intervals without regard to their behaviors.
 Animals related whatever they were doing to the reward, and wound up doing odd things.

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Skinner discovered that stimuli (cues) provide information about the opportunity for reinforcement (reward).
 The stimulus sets the occasion for the behavior.
Fading – gradually transferring stimulus control from a simple stimulus to a more complex one.
Operant behavior is controlled by both stimuli and reinforcers.

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Discriminative stimuli act as “occasion setters” (see Chap 5) in classical conditioning.
 The stimulus that signals the opportunity for responding and gaining a reward is S D .
 The stimulus that signals the absence of opportunity is S
D
.

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Primary reinforcer
– stimuli or events that reinforce because of their intrinsic properties:
 Food, water, sex
Secondary reinforcer
– stimuli or events that reinforce because of their association with a primary reinforcer:
 Money, praise, grades, sounds (clicks)
 Called conditioned reinforcers .

 Secondary (conditioned) reinforcers reward intermediate steps in a chain of behavior leading to a primary reinforcer.
 Secondary reinforcers can also be discriminative stimuli that set the occasion for more responding.
 Classical conditioning is a glue that enables chains of behavior leading to a goal.