Announcement

• The bookstore starts returning books on Oct. 3rd. If you haven't purchased the text (?) or the study guide, you should do it now.

Definition of Learning

• Change in behavior, thoughts, or feelings of an organism that results from experience.
• Differs from "preprogrammed" behaviors, such as reflexes, instincts, and imprinting.
• Three major types: Classical conditioning, instrumental conditioning, & observational learning.

Classical Conditioning

• The way organisms learn the meaningful relations between events.
• Discovered by Ivan Pavlov; often called "Pavlovian conditioning."

Concepts & Terms

• Unconditioned stimulus (US)
• Unconditioned response (UR)
• Conditioned stimulus (CS)
• Conditioned response (CR)

Examples

• Vignettes
• Addiction, drug tolerance
• Television commercials
• Emotional reactions

What are US, UR, CS, & CR?

• Natalie goes to the park, and plays next to a tree. She bumps into a branch that houses a wasp nest. After she recovers from multiple stings, she refuses to go near the park.
• Susan and Dan heard Faith Hill's song, "This Kiss," during their first date, which was wonderful. Now when Susan hears the song, she gets goosebumps, and her heart flutters.

Emotional reactions

• Would you be willing to eat fudge that had been formed into the shape of dog feces?
• Would you be willing to drink apple juice into which a sterilized cockroach had been dipped?

What is necessary for learning to occur?

• A stimulus will acquire signaling properties, and become a CS, whenever it provides information about the occurrence of the US.
• Classical conditioning is not passive; it is the result of organisms seeking to learn when events predict or cause other events.

This principle explains why

• CS should occur before US.
• CS usually must precede US closely in time.
• US must not occur frequently in the absence of the CS (Rescorla's experiment).
• Phenomenon of "blocking."

Second-order Conditioning

• A conditioned stimulus can be used to condition a second stimulus.
• Typically is less stable than direct conditioning.

Stimulus Generalization
"He who is bitten by the snake fears the lizard." -Bugandan proverb

• Stimuli that are similar to the CS will elicit a CR.
• The less similar the stimulus, the less probable or intense is the CR.
• Little Albert: CS was a white rate; CR generalized to a rabbit, a fur coat, package of cotton, but not a block of wood.

Phases of Conditioning

• Acquisition
• Extinction
• Spontaneous recovery
• Highlights the difference between learning and performance.

Qualitative Relation Between the Stimulus and the Response

• Not all CS-US pairings are equal; some associations are easy to learn, others are more difficult to learn.

Garcia and Koelling's Study

• Three CS presented together: Taste of H2O, light, & noise;
• Rats were then mildly poisoned or shocked.
• Rats were then exposed to taste CS or to light & noise CS alone.
• Could rats learn that a funny taste predicted sickness or shock or that light/noise predicted sickness or shock?

Garcia & Koelling's Findings

• Conditioning could occur after only a single learning trial.

Applications

• Combating negative effects of chemotherapy
• Predator control

Summary

• Learning is a change in behavior that results from experience.
• Classical conditioning is a form of learning in which organisms learn the important signaling properties of events.
• Put another way: Classical conditioning is how organisms learn the causal structure of the world.