PSY402 Theories of Learning

1. PSY402Theories of Learning Wednesday, November 19, 2003 Chapter 6 -- Traditional Theories (Cont.)

2. Single-Trial Learning • All-or-nothing (single-trial) learning has been difficult to demonstrate. • Voeks – found single-trial learning of an eye-blink response in humans. • Other studies report gradual learning. • Spence proposed a threshold explanation of single-trial learning using incremental learning theory.

3. Spence’s Acquired Motives • Spence was a colleague of Hull. • Spence elaborated the idea that reward size matters (K in Hull’s theory). • It isn’t enough to say that reward size matters – how specifically does it affect behavior? • Spence proposed a mechanism.

4. Goal Responses • Reward elicits an unconditioned goal response RG. • This response produces an internal stimulus state SG that motivates consummatory behavior. • Reward value determines the size of the goal response RG.

5. Anticipatory Goal Responses • Cues become associated with reward through classical conditioning. • These produce an anticipatory goal response rG. • Cues lead to internal stimulus changes sG that motivate behavior. • Thus Pavlovian conditioning motivates approach behaviors.

6. Amsel’s Frustration Theory • Amsel applied Spence’s theory to avoidance of aversive events: • Frustration motivates avoidance. • Frustration suppresses approach. • Nonreward produces unconditioned frustration response RF. • The stimulus associated with it SF motivates escape behavior.

7. Anticipatory Frustration Response • As with goal states, classical conditioning results in anticipatory frustration response rF. • The conditioned stimuli associated with them sF motivate avoidance of a frustrating situation. • Example: car that won’t start. • SF motivates leaving the car, sF motivates selling it.

8. Mowrer’s Two-Factor Theory • Mowrer proposed a drive-based two-factor theory to avoid explaining avoidance using cognitive (mentalistic) concepts. • Avoidance involves two stages: • Fear is classically conditioned to the environmental conditions preceding an aversive event. • Cues evoke fear -- an instrumental response occurs to terminate the fear.

9. Mowrer’s View (Cont.) • 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. • Fear reduction rewards the escape behavior.

10. Criticisms of Two-Factory Theory • Avoidance behavior is extremely resistant to extinction. • 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. • Avoidance persists if long latency cues exist closer to the aversive event.

11. Is Fear Really Present? • When avoidance behavior is well-learned the animals don’t seem to be afraid. • An avoidance CS does not suppress operant responding (no fear). • 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.

12. Avoidance without a CS • Sidman avoidance task – an avoidance response delays an aversive event for a period of time. • 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?

13. Kamin’s Findings • Avoidance of the UCS, not just termination of the CS (and the fear) matters in avoidance learning. • Four conditions: • Response ends CS and prevents UCS. • Reponse ends CS but doesn’t stop UCS. • Response prevents UCS but CS stays. • CS and UCS, response does nothing (control condition).

14. D’Amato’s Acquired Motive View • D’Amato proposed that both pain and relief motivate avoidance. • Anticipatory pain & relief responses. • Shock elicits unconditioned pain response RP and stimulus SP motivates escape. • Classically conditioned cues sP elicit anticipatory pain response rP that motivates escape from the CS.

15. Anticipatory Relief Response • Termination of the UCS produces an unconditioned relief response RR 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

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

17. How is rG Measured? • Anticipatory goal responses were initially measured as peripheral nervous system (ANS) response. • No consistent relationship between such measures and behavior could be found. • Now, Rescorla & Solomon propose that these anticipatory states are due to CNS activity (brain states).