Classical/Pavlovian Conditioning: Compound Stimulus Effects

compound stimulus effects

A phenomenon where two stimuli combined produce a stronger response than either stimulus alone.
Example: A tone (A) and a light (B) together lead to a stronger response than just A or B.

sensory preconditioning

Learning that occurs when two stimuli are associated before conditioning.
Example:

• Procedure:

  • Phase I: Group 1 (A→B), Group 2 (nothing).

  • Phase II: All get B+.

  • Test: Does A elicit a CR?

• Results: Group 1 shows CR to A; Group 2 does not.

• Significance: Animals can form S-S associations without reinforcement.

significance of sensory preconditioning

Animals can form S-S associations without reinforcement

overshadowing

When a more salient stimulus overshadows a less salient one, affecting learning.
Example:

• Procedure:

  • Phase 1: Groups 1 & 2 control; Group 3 (AX+).

  • Test: Does A or X elicit CR?

• Results: A elicits CR, X does not.

• Significance: Salient CS competes for attention; more salient wins.

significance of overshadowing

Salient CS competes for attention; more salient wins.

blocking

Prior conditioning to one stimulus prevents learning about a new stimulus when both are present.
Example:

• Procedure:

  • Phase I: Group 1 (B+), Group 2 (nothing).

  • Phase II: All get BY+.

  • Test: Does Y elicit CR?

• Results: Y elicits CR in Group 2, not Group 1.

• Significance: Learning occurs only when new information is provided.

significance of blocking

Learning occurs only when new information is provided