Week 3

Question 1

Blocking

Answer 1

Blocking = slower learning
(of association between the neutral stimulus and the US)
When a neutral stimulus and an excitatory stimulus
(CS+) together are paired with the US

Question 2

Blocking- demonstrated by Kamin

Answer 2

Rats divided into 2 groups
control group:
Phase 1: rats saw both a light and heard a noise and then got shocked. Repeat
until rats developed a CR
Phase 2: Kamin then tested whether the rat reacted to just the light by trying to avoid being shocked. YES!
Blocking group: phase 1a:
rats heard a noise and then got shocked until they developed a CR phase 1b:
rats then heard the noise and saw the light and then got shocked
Phase 2: Kamin then tested whether the rat reacted to just the light by trying to avoid being shocked. NO!
Rats in both the blocking and control groups had seen the light and then been shocked exactly as
many times
• However, the rats
reacted differently

Question 3

The Blocking Effect &

Hidden Assumptions

Answer 3

§ Any stimulus can	be	
paired with any response (equipotentiality)	
§ The more two stimuli	
are	paired, the stronger the	individual will	associate them	
(contiguity)	
§ Pairing	the light	with	
the	shock didn’t lead	
to conditioning	
§ The control	group and	
blocking	group	had	the	
noise+light/shock	pair	
the	exact	same	
amount	of	times

Question 4

Superconditioning

Answer 4

Superconditioning= faster learning
(of association between the neutral stimulus and the US)
When a neutral stimulus and an inhibitory stimulus (CS-)
together are paired with the US

Question 5

Superconditioning- Rescorla

Answer 5

Phase 1: a tone was played in the
absence of a shock – tone became cue of
safety (Inhibitor)
Phase 2: a tone & a light presented together, followed by a shock
Phase 3 (test): Finally rats were
presented the light alone – rats in this
group showed stronger conditioning to
the light than rats in a control group that
did not go through phase 1

Question 6

Blocking and Superconditioning

- Is paring of CS and US sufficient for learning?

Answer 6

No, surprise is necessry for learning

Question 7

Free Energy Principle

Answer 7

• Global theory about how the brain works
• Tries to provide a unified account of action, perception and learning for adaptive systems
• The free-energy principle
– “any self organizing system that is at equilibrium with its environment must minimize its free energy”.
– “A formulation of how adaptive systems (that is,
biological agents, like brains) resist a natural tendency
to disorder.”
• Biological systems must maintain their states
despite a constantly changing environment (both
external and internal)
• The physiological and sensory states in which an organism can be is limited - low entropy
• Entropy = surprise. a “fish out of water” has high entropy
• Biological agents must minimize the long-term
average of surprise to keep sensory entropy low.

Question 8

Classical conditioning phenomena..cont’d:
CS pre-exposure (latent inhibition)
• Does CS pre-exposure affect conditioning?

Answer 8

Yes, eg. pre-exposed to CS1-yellow light, then CS2- blue light and compering acquisition to CS1- yellow light
CS pre-exposure
slows subsequent conditioning for that CS compared to a new stimulus

Question 9

What causes CS pre-exposure effects?

Answer 9

Possible Explanations
§Habituation
§Conditioned inhibition

Question 10

Is CS pre-exposure due to habituation?

Answer 10

No
§Context	specificity	
§CS	pre-exposure	is	context	specific
§Habituation	is	not	context	specific	(it	occurs	
regardless	of	the	context)

Question 11

Is CS pre-exposure due to conditioned inhibition –

Retardation test

Answer 11

• Must	pass	retardation	& summation	tests	
• Retardation	test	
– Test:	
• Group	1:Pre-exposed to CS1	
• Group	2: Pre-exposed to	different	CS2	
• Compare acquisition to CS1	
• CS	pre-exposure	retards		
(slows) learning

Question 12

Is CS pre-exposure due to conditioned inhibition? –

Summation Test

Answer 12

No
When paired with an excitatory stimulus (E), a pre-exposed stimulus (I;
right red bar) reduces responding less than a true inhibitor (I; left red
bar). CS pre-exposure fails the summation test!

Question 13

Conditioning phenomena- Condition inhibition

Answer 13

Passes both summation and retardation test

Question 14

Conditioning phenomena- CS pre-exposure/Latent inhibition

Answer 14

Does not pass summation test, only retardation test

Question 15

More classical conditioning phenomena:

Generalisation-Discrimination

Answer 15

§Does classical conditioning generalise?
§ Test:
§Train with CS1-US
§Test different groups with: CS1, CS2, CS3 …
§Most generalisation to similar stimuli

Question 16

Example generalisation

Answer 16

Little Albert

Question 17

Moore (1972) experiment

Answer 17

Rabbit’s	eyeblink	response	
• 16	rabbits		
• US: Mild electric	shock	
• UR: Eye blink	
• CS+: 1200 Hz tone	
• Test stimuli during	 extinction:	
–  400Hz, 800Hz, 1200Hz,	
1600Hz,	2000Hz.

Question 18

Discrimination

Answer 18

Does generalisation last?
Not after extensive training trials
-Each exposure of CS1-US refines association
-Provided CS2 or CS3 not ever presented with US
-Reduced responding to CS2, CS3 … over time
Evolutionary benefits?

Question 19

The basic principles

Answer 19

Generalisation

Discrimination

Question 20

Generalisation

Answer 20

Other (similar) stimuli may also produce the CR

The more similar to the original CS, the more likely it is to elicit the CR

Question 21

Discrimination

Answer 21

Early on during acquisition, generalisation maycause the learner to respond to a variety of stimuli
As learning continues, the organism learns which
CS seems to be best associated with US (they
discriminate)

Question 22

The two parts to science

Answer 22

Research finds that trace conditioning is less
effective than short-delay conditioning
– Theory explains why trace conditioning is less
effective than short-delay conditioning

Question 23

Models in psychology

Answer 23

A model
– is a formal attempt to explain a wide body of research
– Makes predictions
– Predictions can be tested
• Some models are mathematical: e.g. ∆V =αβ (λ−V)

Question 24

Developing a Formal model of classical conditioning

Answer 24

Such a model should be independent of
conditioning procedure
§ It should generate testable predictions
§ Today: The Rescorla Wagner Model
§ Explains how organism learns the prediction of the US

Question 25

What is the Rescorla-Wagner model?

Answer 25

The level of conditioning is a result of an internal comparison between: § Expected strength of the US § Actual strength of the US § Expectation is based on prior experience with the US (i.e., previous trials) § Strength of the US is fixed (e.g., mild shock)

Question 26

what are the different parts to | The Rescorla-Wagner Model (1972)

Answer 26

∆V = αβ (λ −V) λ – Magnitude of associative value that can be conditioned for CS; actual CS value V - Current associative value of CS (expectations about the CS-US association/CSvalue) Surprisingness of the US ∆V - Change in associative value of CS α - salience of the CS β - strength of the US to promote conditioning

Question 27

Assumptions and the rescorla-wagner model

Answer 27

Previous models assumed that a CR gets stronger the more a CS is paired with a US. • Rescorla Wagner model basically assumes that a CR gets stronger if the CS-US pair is

Question 28

Rescorla-Wagner & the Blocking Effect

Answer 28

``` Kamin (1968) found that rats ignored a light if the light happened at the same time as a noise that they had previously learned predicted a shock. • This is the blocking effect. • violates the frequency principle • Rescorla-Wagner explain this by saying that the light doesn’t change how surprised the rat is at being shocked. • The rat ignores the light because it already expects the shock to happen because of the noise. ```

Question 29

Rescorla-Wagner, & Superconditioning

Answer 29

• The Rescorla-Wagner model also predicted that there would be superconditioning (the opposite of blocking). • Superconditioning occurs when a previously learnt stimulus is combined with a new stimulus • In superconditioning, the old stimulus is inhibitory and the combination is excitatory -> surprise that US is presented! • The organism develops an association between the new stimulus & the excitatory CS.

Question 30

Attentional models of classical conditioning

Answer 30

* Rescorla-Wagner model is not Perfect… * Has difficulty explaining/predicting CS Preexposure (Latent inhibition) * Other models have been proposed to try and explain such phenomena * Mackintosh (1975) * Pearce and Hall (1980)

Question 31

Taste Aversion

Answer 31

• In typical classical conditioning, acquiring a CR requires dozens of trials associating the CS and the US • In typical classical conditioning, long-delay conditioning (more than a few seconds) is less effective • Yet… – You can acquire a taste aversion after one single association. – The time between you eating the food and getting sick can be as long as 24 hours • Of course, while it goes against the rules, it does so for good reason: – It takes a while to feel sick after eating food – And it’s really important to know which foods are bad to eat as quickly as possible

Question 32

``` Some classical conditioning phenomena: Garcia effect (preparedness) ```

Answer 32

§Are all associations learned equally? § Equipotentiality: Every CS has the same potential to be associated with a US (Pavlov) §Garcia & Koelling (1966) showed this assumption does not hold! Some associations are learned faster than others!

Question 33

Classical fear conditioning: contemporary research

Answer 33

Differential conditioning paradigm fear-relevant: snake (CS+ excitory): snake (CS- inhibitory) fear-irrelevant: mushroom (CS+ excitory): mushroom (CS- inhibitory) Acquisition: a CS+ was paired with a US shock; the other type of stimulus was not paired with shock (CS-); • Extinction: SCR (skin conductance response) was the CR.

Question 34

Classical conditioning in everyday life: addiction

Answer 34

Many users die after taking a fairly usual dose in an unfamiliar environment • Siegel et al. (1982) argued that this is because the body’s tolerance to heroin is influenced by classical conditioning There are usually similar environmental cues when is taken • The endocrine system associates these cues with taking, and ramps up the tolerance response • If those cues are not present, the body isn’t as prepared to tolerate heroin • Overdose is more likely

Question 35

Classical conditioning and addiction: ‘overdose’ experiment (Siegel et al., 1982)

Answer 35

``` § Training: § Experimental: H in room A, Placebo in room B § Control: Placebo in both rooms § Test: Higher dose of heroin § Same: H in A §Different: H in B § Control: H §DV: Mortality §Same: 32.4% §Different: 64.3% §Control: 96.4% §Context conditioning affects tolerance ```

Question 36

Classical conditioning in clinical settings

Answer 36

• If phobias are caused by classical conditioning… • …you can use classical conditioning techniques to eliminate or reduce them. • How do you extinguish a CR? • By presenting the CS without the US • In clinical psychology, a program of presenting the CS without the US is called systematic desensitisation • Phobias persist because: – people avoid situations where they see the phobic object (avoid opportunities to extinguish fear) – They can be self-sustaining – e.g., trying to overcome a fear of crowds can leave you feeling very embarrassed • Systematic desensitisation gradually exposes the client to the phobic object in a gradual way 1. A fear hierarchy is constructed 2. Participant is given relaxation training 3. Psychologist gradually exposes the client to things higher on the fear hierarchy as they relax E.g., after 3.5 years, 60% who were systematically desensitised continued to fly (see Choy et al., 2007 for review)