Other Behaviour Revision

Question 1

Instrumental and classical conditioning working together: Extending the two-process account to drug addiction

Answer 1

In addition to the role of classically conditioned cues in drug addiction, instrumental mechanisms come into play
There can be a chain of responses which bring the addict into contact with the drug (US); initial responses most likely just result in exposure to the cues (CSs) associated with drug-taking which can act as secondary reinforcers (e.g., the cigarette in the hand)
Negative reinforcement, which involves reducing exposure to aversive stimuli, plays an important role for drugs which produce withdrawal symptoms
Withdrawal symptoms can also be triggered by classically conditioned cues…

Question 2

Associative learning in addiction

Answer 2

Addiction results in serious behavioural problems and health effects (some acute risks, some more long-term)
Dopamine (DA) is implicated based on evidence that
(1)DA pathways are the substrate for normal rewards
(2)Addictive drugs are direct or indirect DA agonists

Question 3

Associative learning in schizophrenia

Answer 3

Schizophrenia is a serious mental disorder, characterised by hallucinations and delusions

Dopamine (DA) is implicated based on evidence that

(1) DA agonists can induce schizophrenic like symptoms
(2) Schizophrenia is treated with DA antagonists

Question 4

Can animals learn to count?

Answer 4

learning a discrimination based on number does not require the ability to count

Question 5

Can animals learn to time?

Answer 5

some conditioning models try to explain timing, e.g. Rescorla-Wagner model, adapted to allow stimulus change over the course of its presentation

Question 6

Do animals have any concept?

Answer 6

many concepts are based on the sharing of common features by exemplars in a particular category

Question 7

Do long delay conditioned stimuli develop inhibitory properties?

Answer 7

Abstract: In long-delay conditioning, a long conditioned stimulus (CS) is paired in its final segments with an unconditioned stimulus. With sufficient training, this procedure usually results in conditioned responding being delayed until the final segment of the CS, a pattern of responding known as inhibition of delay. However, there have been no systematic investigations of the associative structure of long delay conditioning, and whether the initial segment of a long delay CS actually becomes inhibitory is debatable. In an appetitive preparation with rat subjects, the initial segment of long delay CS A passed a retardation (Experiment 1a) but not a summation (Experiment 1b) test for conditioned inhibition. Furthermore, retardation was observed only if long delay conditioning and retardation training occurred in the same context (Experiment 2). Thus, the initial segment of a long delay CS appears to share more characteristics with a latent inhibitor than a conditioned inhibitor. Componential theories of conditioning appear best suited to account for these results.

Question 8

Varieties of inhibition

Answer 8

Conditioned inhibition
Latent inhibition
External inhibition
Inhibition of delay

Question 9

Conditioned inhibition

Answer 9

CR is suppressed because inhibitor signals US not expected on this occasion; key tests are summation and retardation

Question 10

Latent inhibition

Answer 10

pre-exposure to a stimulus (without any US) inhibits later conditioning (both excitatory and inhibitory)

Question 11

External inhibition

Answer 11

presence of a novel cue inhibits CR through a mechanism more like distraction

Question 12

Inhibition of delay

Answer 12

holding back on the CR when the CS is a long one

Question 13

Classical & instrumental conditioning occurring together

Answer 13

Instrumental learning easier if the response is an automatic reaction to the US
•Pavlov’s dog salivating
•Easy to learn an approach response produces food
•Hard to learn that withholding responding is what you need to do to get food
•Autoshaping
•Avoidance learning

Question 14

Avoidance conclusions

Answer 14

According to two-process learning theory, through classical conditioning stimuli gain reinforcing and motivational properties
Avoidance learning can be very persistent because the execution of the avoidance response generates potential safety signals
Thus CIs protect conditioned fear from extinction

Question 15

Conditioned inhibition

Answer 15

Conditioned inhibition
Stage 1: CSa->US
Stage 2: (CSa+CSb)->no US

Prior training (in stage 1) sets up CSa as a predictor of the US
There will be later learning (in stage 2) to the added in CS
CSb is informative, it means ‘no US’

Question 16

Blocking

Answer 16

Blocking Control
Stage 1: CSa->US nothing
Stage 2: (CSa+CSb)->US (CSa+CSb)->US

Prior training (in stage 1) reduces later learning (in stage 2) to the added in CS
Prior training makes CSb ‘redundant’
Blocking designs are similar to those used to set up conditioned inhibition BUT the US still occurs after the compound presentation in blocking designs…

Question 17

Latent inhibition (LI)

Answer 17

Pre-exposure Control
Stage 1: CSa->nothing CSb->nothing
Stage 2: CSa->US CSa->US

Stimulus pre-exposure (in stage 1) reduces later learning (in stage 2) when the stimulus is now relevant
Pre-exposure makes CSa ‘irrelevant’
LI can apply to both excitatory and inhibitory stimuli, i.e. LI of a potential inhibitor

Question 18

Overshadowing

Answer 18

Overshadowing                    
OS: (CSN+CSL)->US
Controls: (CSn+CSL)->US        
Single stage compound
conditioning procedure
CSN, CSn and CSL predict the US
Followed by a test of conditioning to each of the elements of the compound (Figure shows results for CSL)
The louder CS (N) overshadows the alternative CS (L)

Question 19

Translating back to animal models

Answer 19

• Loss of the “selectivity which normal attention ordinarily exercises among the sensory impressions” (Bleuler, 1911; Hemsley, 1987, 1993; Gray et al., 1991; Kapur, 2004)
• Core deficit suggests use attentional measures, e.g., LI
• Low LI = openness to environmental stimuli irrespective of their past significance
• Translational research, with humans…
• Rat model to tell us which neurotransmitter systems and brain structures are important

Question 20

How the model came about and continues to develop…

Answer 20

Better drugs are needed for schizophrenia (SZ)
SZ is characterised by attentional problems, some of which can be measured in animals
Amphetamine is a drug model for SZ

LI is impaired in SZ and by amphetamine
Model extends to studies of individual differences (psychoticism, schizotypy)

Rat model is now used to identify neural substrates
Effects on LI are compared to those seen using other methods to weaken associative learning