1. PSY402 Theories of Learning
Wednesday
March 12, 2003

2. Problems with Rescorla-Wagner
Overshadowing – salient cues have more associative strength.
Sometimes a salient cue potentiates another cue instead of overshadowing.
Garcia says cues are indexed.
R-W says cues are seen as unitary stimulus.
Unclear which explanation is correct.

3. More Problems
CS preexposure effect – appearance of CS without UCS prior to learning weakens learning.
Shouldn’t have any effect according to Rescorla-Wagner theory, but it does.
Cue-deflation effect – extinction of a more salient cue enhances learning for the less salient cue.
Should be no change according to R-W.

4. Comparator Theory
If two CS’s are associated, extinction of one should reduce responding to the other.
Sometimes true, other times not.
CS-UCS associations exist for many stimuli but are exhibited only for the strongest.
CS’s are judged in relation to each other.

5. Attentional View
Mackintosh – learned irrelevance occurs during preexposure of CS.
Animals exposed to a novel stimulus exhibit an orienting response.
No orienting with preexposure.
Habituation results in failure of conditioning.
Pairing of CS/UCS in novel context results in learning.

6. Retrospective Processing
Most theories assume the level of responding will be constant after learning.
Baker & Mercier suggest association can change after learning.
Retrospective processing – CS-UCS contingency reevaluated after learning.
Backward blocking – support for theory
Suggests animals have mental representations, memory for events.

7. Operant Conditioning Nature of reinforcement: Behavioral economics:
Premack’s probability differential theory
Response deprivation theory
Behavioral economics:
Behavioral allocation – blisspoint
Choice behavior – Herrnstein’s matching law.
Momentary maximization theory
Delay-reduction theory

8. Probability-Differential Theory
Premack – a reinforcer can be any activity that is more likely to occur than the reinforced behavior.
Manipulators vs eaters
High probability behaviors can be used as reinforcers of low probability behaviors.
Frequency of the reinforcer decreases when it is made contingent on another response.

9. Response Deprivation Theory
Timberlake & Allison – deprivation occurs when an activity is used as a reinforcer and is not freely emitted.
The activity is reinforcing because it satisfies the deprivation created.
The animal tries to return to its pre-deprivation level of responding.
Activities can be reinforcing even if their baselines were not higher.

10. Behavioral Allocation
Blisspoint (paired basepoint) – the free operant level of two responses.
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.

11. Problems with Contingencies
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.

12. Choice Behavior
Herrnstein’s matching law – describes how animals act when they have two or more choices.
Different responses have different schedules of reinforcement.
Responding to each choice is proportionate to the reinforcement for each choice – after learning.
This can be expressed mathematically.

13. Delayed Gratification
Why does anyone choose a smaller reward part of the time?
Animals and people typically choose a small immediate reward over a larger delayed reward.
Large rewards are selected when:
The choice is made in advance of reward.
Reinforcers are not visible or reward is already present (pleasurable activity).

14. Complexities of the Matching Law
Maximizing law – sometimes the aim is to obtain as many rewards as possible.
Explains FR-10 vs FR-40 schedules.
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.