2021-PSYC-4050-Psychology-of-Learning-Lecture-Notes-Theories of Appetitive and Aversive Conditioning PDF

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PSYC 4050: Psychology of Learning Lecture Notes

Theories of Appetitive and Aversive Conditioning 

Operant Conditioning



The nature of reinforcement:



o

Premack’s probability differential theory

o

Response deprivation theory

Behavioral economics: o

Behavioral allocation – blisspoint

o

Choice behavior – Herrnstein’s matching law.

o

Momentary maximization theory

o

Delay-reduction theory

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Probability-Differential Theory

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Premack – a reinforcer can be any activity that is more likely to occur than the reinforced behavior. o



Manipulators vs eaters

High probability behaviors can be used as reinforcers of low probability behaviors. o

Frequency of the reinforcer decreases when it is made contingent on another response.



Activities can be Reinforcers

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Response Deprivation Theory

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PSYC 4050: Psychology of Learning Lecture Notes

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Timberlake & Allison – deprivation occurs when an activity is used as a reinforcer and is not freely emitted. o

The activity is reinforcing because it satisfies the deprivation created.

o

The animal tries to return to its pre-deprivation level of responding.



Activities can be reinforcing even if their initial baselines were not higher.

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Behavioral Allocation

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Blisspoint (paired basepoint) – the free operant level of two responses. o



Unrestricted responding with two choices of behaviors.

Blisspoint is used to figure out how much behavior an animal will engage in to obtain a reward.



Animals try to get as close to the blisspoint as possible.

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Finding the Blisspoint

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Contingency Lines for Rewards

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Problems with Contingencies

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Blisspoint is established by looking at behavior before a contingency is established.



The established contingency must take blisspoint into account or it may not increase desired behavior.



Choice Behavior

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Herrnstein’s matching law – describes how animals act when they have two or more choices.

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PSYC 4050: Psychology of Learning Lecture Notes

o

Different responses have different schedules of reinforcement.

o

Responding to each choice is proportionate to the reinforcement for each choice – after learning.

o

This can be expressed mathematically.



Mathematical Expression



The formula for the matching law is:

where R1 and R2 are the rates of response for two alternative responses And r1 and r2 are rates of reinforcement for those responses 

Law Predicts Pecking Behavior



Delayed Gratification



Why does anyone choose a smaller reward part of the time? o

Animals and people typically choose a small immediate reward over a larger delayed reward.



Large rewards are selected when: o

The choice is made in advance of reward.

o

Reinforcers are not visible or reward is already present (pleasurable activity).



Complexities of the Matching Law

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PSYC 4050: Psychology of Learning Lecture Notes

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Maximizing law – sometimes the aim is to obtain as many rewards as possible. o

Explains FR-10 vs FR-40 schedules.

o

Doesn’t work for VI vs VR schedules.



Momentary maximization theory – choose best alternative at the time.



Delay reduction theory – choose what will get the reward the fastest.

 Aversive Theories: Explaining Avoidance 

The existence of avoidance behavior implies a cognitive process: o

Behaving in order to prevent an aversive event.



Behaviorists like Hull needed to explain this without cognition.



Mowrer’s two-factor theory was developed to explain this – but it has problems needing explanation.



Mowrer’s Two-Factor Theory

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Mowrer proposed a drive-based two-factor theory to avoid explaining avoidance using cognitive (mentalistic) concepts.



Avoidance involves two stages: o

Fear is classically conditioned to the environmental conditions preceding an aversive event.

o

Cues evoke fear -- an instrumental response occurs to terminate the fear.



Mowrer’s View (Cont.)

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PSYC 4050: Psychology of Learning Lecture Notes

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We are not actually avoiding an event but escaping from a feared object (environmental cue).



Miller’s white/black chamber – rats escaped the feared white chamber, not avoided an anticipated shock.

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Fear reduction rewards the escape behavior.



Criticisms of Two-Factory Theory

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Avoidance behavior is extremely resistant to extinction. o



Should extinguish with exposure to CS without UCS, but does not.

Levis & Boyd found that animals do not get sufficient exposure duration because their behavior prevents it. o

Avoidance persists if long latency cues exist closer to the aversive event.



Is Fear Really Present?



When avoidance behavior is well-learned the animals don’t seem to be afraid. o

An avoidance CS does not suppress operant responding (no fear).

o

However, this could mean that the animal’s hunger is stronger than the fear.



Strong fear (drive strength) is not needed if habit strength is large.



Avoidance without a CS

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PSYC 4050: Psychology of Learning Lecture Notes

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Sidman avoidance task – an avoidance response delays an aversive event for a period of time. o

There is no external cue to when the aversive event will occur – just duration. Temporal conditioning.



How do animals learn to avoid shock without any external cues for the classical conditioning of fear?



Kamin’s Findings

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Avoidance of the UCS, not just termination of the CS (and the fear) matters in avoidance learning.



Four conditions: o

Response ends CS and prevents UCS.

o

Reponse ends CS but doesn’t stop UCS.

o

Response prevents UCS but CS stays.

o

CS and UCS, response does nothing (control condition).



Both Factors are Important



D’Amato’s Acquired Motive View

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D’Amato proposed that both pain and relief motivate avoidance. o



Anticipatory pain & relief responses.

Shock elicits unconditioned pain response RP and stimulus SP motivates escape.

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PSYC 4050: Psychology of Learning Lecture Notes

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Classically conditioned cues sP elicit anticipatory pain response rP that motivates escape from the CS.



Anticipatory Relief Response



Termination of the UCS produces an unconditioned relief response R R with stimulus consequences SR.



Conditioned cues elicit an anticipatory relief response rR with stimulus consequences sR.



Example: dog bite elicits pain response, sight of dog elicits anticipatory pain, house elicits relief



A Discriminative Cue is Needed



During trace conditioning no cue is present when UCS occurs and no avoidance learning occurs.



A second cue presented during avoidance behavior slowly acquires rR-s R conditioning.



Similarly, in a Sidman task, cues predict relief -- associated with avoidance behavior, not the UCS.



A Second Cue Helps Trace Learning



Thorndike’s Negative Law of Effect



Thorndike suggested that punishment weakens an S-R bond. o

Skinner’s finding that suppression of behavior is temporary contradicts this.

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PSYC 4050: Psychology of Learning Lecture Notes

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The effect of punishment must be something different than weakening of the S-R bond.



Guthrie’s View of Punishment



When punishment occurs, the response to it is conditioned to the environment during the event. o



Freezing, jumping, flinching.

The effect on behavior depends on the UCR elicited by the shock. o

Shock to forepaws inhibits running but a shock to hindpaws facilitates it.

o

Monkeys struggle more when shocked.



Guthrie’s Competing Response Theory



Guthrie suggested that punishment works only if the response elicited by the punishment is incompatible with the punished behavior. o

Gerbils punished for standing upright do it more, not less.



Problems with Guthrie’s Theory



Response competition alone is insufficient to make punishment effective.



When punishment is contingent instead of just co-occurring, it is more effective. o

Contingent means the punishment happens only when the behavior occurs, not independent of it, randomly



Este’s Motivational View

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PSYC 4050: Psychology of Learning Lecture Notes

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When a behavior is rewarded, the motivational system becomes associated with the behavior. o

The response occurs the next time the motivational system is activated.



Punishment works by changing the motives. o

Stimuli associated with punishment inhibit the motivational state.



Support for Estes



Thirsty rats were trained to lever press for water and “dry lick” for air on alternate days. o

Punishment of both behaviors had a greater effect on dry licking (a thirst-related behavior) than lever pressing.

o

If the behavior rather than the motive were being suppressed no such difference should occur.

o

Results differed with hungry rats.

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