Chapter 4

Classical Conditioning Terminology

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

Example: Food

(Figure 1)

Example: Eyeblink Conditioning

• Airpuff on eye
• Blink
• UR vs. CR eyeblinks
• UR blink faster than CR blink

Example: Conditioned Suppression

• Also called conditioned emotional response (CER)
• US: aversive event
• UR: startle, jump, vocalization, freeze
• Lever press
• Suppression of pressing

Example: Skin Conductance Response (SCR)

• Galvonic skin response
• Fluctuations in perspiration
• Electric shock increases SCR
• CS

Example: Taste Aversion

• Very strong
• Very persistent
• Usually conditioned after one presentation
• Experiment
• Rats fed novel food
• Injected with lithium chloride
• Choice: novel food or regular food
• Chose regular food

Stimulus Substitution Theory

• Pavlov’s theory
• Through repeated pairings of the CS and the US the CS becomes a substitute for the US so that all responses initially elicited only by the US are now also produced by the CS

Problems with S-S theory

• CS not a complete substitute for US
• CSs produce different responses
• Conditioned compensatory responses

What is Learned in Classical Conditioning?

• US centre, Response centre, CS centre

(Figure 2)

S-S or S-R Connections?

• S-S Theory
• Two associations

• S-R Theory
• One association

(Figures 3 and 4)

Rescorla’s (1973) Experiment

• Habituation to weaken US-response link
• Conditioned suppression procedure
• Loud noise
• Experimental protocol

(Figure 5)

Aspects of Classical Conditioning

Acquisition

• Acquisition phase
• Asymptote
• Intensity of the US
• Salience of the CS

(Figure 6)

Extinction

• CS not regularly followed by US
• Not time dependent

(Figures 7 and 8)

Spontaneous Recovery

• CS-US association not "erased"
• Return of behaviour
• Inhibition theory

(Figure 9)

Disinhibition

• Condition CS with US
• Full conditioning
• Impose extinction protocol
• Go to full extinction
• Present novel stimulus with CS
• CR will occur

(Figure 10)

Rapid Reacquisition

• After extinction
• Reacquisition of behaviour takes less time than initial conditioning
• CS-US links still present

Excitatory and Inhibitory CSs

• Don’t last forever
• Excitatory CS: good predictor of occurrence of US
• CS+
• Inhibitory CS: good predictor of non-occurrence of US
• CS-

Conditioned Inhibition

• CS- signals the absence of an event
• Experiment
• Tone (CS), salivation (CR)

• Tone: excitatory conditioned stimulus (CS+)
• Light: conditioned inhibitory stimulus (CS-)

(Figure 12)

Problem 1

• Is the light inherently inhibitory?

(Figures 13 and 14)

Problem 2

• Responding to light alone?
• Use experienced animal
• Add new excitatory CS
• Summation test
• Light serves as an inhibitory CS for many excitatory CSs

(Figures 15 and 16)

Generalization and Discrimination

• Generalization

• Discrimination

• Limited by physical senses

Short Delay Conditioning

• Strongest and most rapid
• Simple autonomic responses: 5-30 seconds
• Quick skeletal responses: 0.5 seconds

(Figure 17)

Simultaneous Conditioning

• Weaker than short delay
• CS can’t signal onset of US

(Figure 18)

Trace Conditioning

• From "memory trace"
• Must remember CS
• Other stimuli interfere

(Figure 19)

Long Delay Conditioning

• Other distracting stimuli?
• Timing estimation required

(Figure 20)

Backward Conditioning

• Ignores order
• CS has no predictiveness
• May induce inhibitory conditioning

(Figure 21)

Higher-Order Conditioning

• CSs and USs can be associated
• CSs can be associated with other CSs
• Second-order conditioning

Example: First-Order Conditioning

(Figure 22)

Example: Second-Order Conditioning

(Figure 23)

Applications in…Advertising

• People consider attractive humans authority figures and, therefore, trustworthy
• Pair attractive person (first-order CS) with product (second-order CS)
• Positive feeling is the CR

Sensory Preconditioning

(Figure 24)

Backwards Conditioning

• Keith-Lucas & Guttman (1975)
• Backward conditioning and biological plausibility
• Predator attacks prey

Experimental Procedure

• Rats fed sugar pellets
• Give one-time electric shock (US)
• Lights go out

• Toy hedgehog added (CS)
• Observe rat one day later

Model

• Sugar pellets = grazing
• Shock = pain of attack
• Hedgehog = lion

Control Groups

• Saw hedgehog, but no shock
• Shocked, but didn’t see hedgehog

Results

• Backward conditioning not seen in controls
• In 1, 5, and 10 sec delay groups, got backward conditioning

• Fear induced by hedgehog is CR

Conclusion

• Biologically relevant CSs can cause backward conditioning