Ch 4

Question 1

What makes a good CS and US: novelty of stimuli

Answer 1

• classical conditioning is slower when the stimuli used are familiar to the subject (novel stimulus should have higher rates of responding)
  → latent inhibition (CS pre-exposure) effect: caused by repeated exposures to the CS before the CS is used in conditioning trials (harder to form associations)
  → US pre-exposure effect: caused by repeated exposures to the US before the US is used in conditioning trials

Question 2

What makes a good CS and US: salience of stimuli

Answer 2

• The stimuli to-be-conditioned must be noticeable
  → intensity of US and CS
  → biological relevance to animal model (more naturalistic CS = more salience)
  → biological relevance to animal state (food for hungry animal, water for thirsty animal)

Question 3

What makes a good CS and US: CS-US relevance (belongingness)

Answer 3

• Selective association: do the CS and US “go together” naturally
  → taste “goes with” sickness
  → audio visual “goes with” shock

Question 4

Learning without an US

Answer 4

• Classical conditioning would be very limited if direct exposure to the US was required for learning to occur
  → there are situations where learning (associations) occurs without a US
• higher-order conditioning: CS may serve as a “US” once conditioned
• sensory preconditioning (CS that are paired → aversive US → aversive CR to any of the CS)

Question 5

US as a determining factor for the CR

Answer 5

• The response depends on the US that elicits it
  → ex. Pigeons given the same CS (light) but different US (food or water), gave different responses for each US

Question 6

Stimulus-substitution model (Pavlov)

Answer 6

• CS activates neural circuits previously activated by the US
• CS becomes a surrogate (substitute) US
  Ex. Bell → bone (new neural connection formed after conditioning), bone → saliva (pre-existing neural connection)

Question 7

CS as a determining factor of the CR

Answer 7

Rat example
- rat used as a CS to signal food US
→ predictions based on stimulus - substitution model: rat should bite at or made chewing motions
→ actual results: CS elicited social affiliate CRs (pawing, grooming, crawl-over)

Question 8

CS - US interval as a determining factor of the CR

Answer 8

Quail example
- conditioned male quail with either short or long CS-US interval
→ CS = stuffed quail, US = access to female quail at the end of interval
→ short interval spent more time near CS (went right to consummatory behaviour)
→ long internal was engaged in locomotor behaviour (general / focal search, appetative)

Question 9

S - R learning

Answer 9

New stimulus-response connection between CS and CR
- US becomes unimportant; the CS directly triggers the CR, bypassing the need for the US. The US is no longer needed for the response
- early in conditioning: CS → US → UR
- after extensive conditioning: CS → CR

Question 10

S - S learning

Answer 10

CS activates a mental representation of the US (in line with Pavlov’s stimulus-substitution)
- US remains important
- early conditioning: CS → US → UR
- after extensive conditioning: CS → US representation → CR

Question 11

US devaluation paradigm

Answer 11

Phase 1:
Experiment group 1 and 2 receive same thing (CS → US → CR)
Phase 2:
Experiment group 1: US gets devaluated
Experiment group 2: value of US stays the same

Test:
If S-R, both groups should respond at high levels to CS. If S-S, experiment group 1 should respond at lower levels to CS compared to experiment group 2.

Results:
Support S-S model of learning (devaluation caused a change in behaviour); US is important

Question 12

Blocking effect

Answer 12

Interference of the conditioning of a novel stimulus because of the presence of a previously conditioned stimulus
→ before blocking was discovered it was thought that temporal contiguity (pairing two CS together that predicted a US) was sufficient for learning associations

Question 13

R-W model

Answer 13

• Standard mathematical model for classical conditioning
• Expectation of US related to associative properties of stimuli preceding it (CS)
  → less surprising as trials go on

Symbols:
λ = maximum possible associate strength (what occurs, when learning plateaus)
V = current associate strength (what is expected)
k = related to the salience of the US
(λ - V) = “surprisingness” of US after presentation CS
→ when λ = V, there is no more room for learning (no surprise)

Question 14

R-W and blocking

Answer 14

• When λ = V, one stimulus already perfectly predicts the US
  → when a novel stimulus is presented alongside the old stimulus (which predicts the US), there will be no surprise or associative value

Question 15

The comparator hypothesis

Answer 15

• Comparator cues: other cues present when the target CS is being conditioned
• in blocking paradigm:
  → context: previously trained CS(A)
  → target: CS(B)
• comparator hypothesis states that the notion of responding to CS(B) is blocked, not learning CS(B) itself

Question 16

The comparator hypothesis and blocking

Answer 16

• CH revaluation procedure: after phase 2 ([A + B] → US), eliminate responding to CS(A) through extinction ([A] → no US)
• test for CR to CS(B), a response demonstrates that performance was blocked rather than learning