What does classical conditioning refer to?
LEARNING BY ASSOCIATION
Classical conditioning aka Pavlovian conditioning refers to a situation where an innate (unconditioned) response to a biological (unconditioned) stimulus becomes expressed in response to a previously neutral (conditioned) stimulus after repetitive pairing of the unconditioned and conditioned stimuli
Anxiety/phobias are examples
Different types of conditioning in mouse
Salivatory conditioning (stimulus-food) Eye-blink conditioning (stimulus- air puff) Conditioned suppression (stimulus shock)
What is operant conditioning? Describe it
LEARNING BY REINFORCEMENT
Operant conditioning refers to learning to associate desirable or undesirable outcomes with certain behaviours by receiving reinforcements or punishments for them.
E.g. pressing a lever may be associated with a positive reinforcer (food), which will result in increased probability of this behaviour, or with a punishment aka negative reinforcer (electric shock), which will result in decreased probability of this behaviour. Skinner believed that positive reinforcement is superior to negative reinforcement in shaping behaviour
Addiction is a good example
What is key for conditioning? Describe
Predictability (the US following the CS)
Its intensity increases with the increased probability that US will follow CS
Multiple occurrences of CS-no US can lead to extinction of the association, although full extinction is v difficult to achieve
Spontaneous recovery of the association can occur when the CS is represented after an interval following extinction
Describe how temporal continency is a constraint on learning
This is the delay between the animals act that is being reinforces and the reinforcing stimuli
Important in operant conditioning
immediate reinforcement is more effective in animals than delayed reinforcement, although humans can learn effectively with delayed reinforcement.
Give an examples of conditioned learning
An example of conditioned learning – Paraphilias:
Rachman (1966, 1968) asked why do sexual fetishes occur. One psychological theory involves conditioning the fetishistic object to a ‘normal’ arousing stimulus
Describe Garcia learned taste aversion
- The Garcia effect is a famous example of biologically prepared learning involving learned taste aversion Garcia (1955) – rats drank saccharin-flavoured water in a cage illuminated with red light, then several hours later were given a dose of radiation to make them nauseous.
The rats then later avoided saccharin-flavoured water, but not red light, even if the illness occurred several hours later – contradicted belief that the UR must immediately follow the CS
Also, Garcia discovered that the rats developed aversions to taste, but not to sights or sounds
So Garcia demonstrated these rats could still exhibit learning, but that taste aversion is an example of prepared learning (biological constraints on learning – preparedness to learn specific stimuli)
Garcia proposed that the sweetened water became regarded negatively because of the nausea inducing effects of the radiation, and so began the study of conditioned taste aversion
Conditioned taste aversion is a survival mechanism – allows recognition of foods previously determined to be poisonous, to hopefully allow organism to avoid sickness - The study ran contrary to, and violated several (old) assumptions about classical conditioning:
a) the gap between the CS and the UR can be very long
b) aversion can be learnt in just one trial
c) it violates the assumption of the equivalence of associations (illness almost always linked to food, even if not related e.g. flu virus responsible) – so did not contradict associative theory as a whole but showed that some fears are more easily learnt than others
d) demonstrated that particular stimulus used in classical conditioning doesn’t matter – internal stimulus gave an internal response, external stimulus gave external response, but an external stimulus wouldn’t give internal response and vice versa – red light
Describe learning curves
- Learning Curves predicted by associative theory Rescorla and Wagner (1972) express the acquisition of association - they can show the strength of a positively-correlated cue and the alternative possible cause, the context (e.g. not US)
- Connectionist algorithms model biologically plausible plasticity changes, although evidence for links with mechanisms such as Long term Potentiation (LTP) are weak (Bannerman, 2010)
Examples of maladaptive learning behaviour
Learned helplessness
Agoraphobia
Anticipatory nausea and vomiting
Describe learned helplessness
- Learned helplessness theory (Seligman) = view that clinical depression and related mental illnesses may result from a perceived absence of control of the outcome of a situation
• Seligman (1968) – dogs given inescapable shock in Pavlovian harness repeatedly until it behaves helplessly.
• Once free, shock is now escapable but animals have a learned helplessness reaction so they do not try to escape, and this maladaptive behaviour can only be alleviated by being repeatedly compelled to escape over the barrier.
• Inferred that the maladaptive passive behaviour in dogs could be possible in humans and so could explain the ‘helplessness’ of mental illness. - Dweck & Rapucci (1973) gave children an easy set of maths problems and they were performed well. If then given unsolvable problems, then easy problems again then the children had difficulty solving them
Describe agroaphobia
- Those with agoraphobia fear open or public places – fear of any place where they might be trapped or unable to receive help in an emergency, especially a panic attack – eg. fear being in busy, crowded places such as malls, and in tightly-enclosed spaces
- Vivid memory of places where panic attacks have occurred, so greatly fear those places, and that fear generalizes to all similar places; by avoiding those places, they reduce their anxiety and their avoidance behaviour thus is highly reinforced
- Experience little anxiety in particular places (eg. own homes), and this reduction of anxiety is also highly reinforcing, leading them to confine themselves to these ‘safe’ spaces – Salkovskis (1991) has labelled such avoidance as ‘safety behaviours’
- Hypervigilance of body sensations, and association of slight changes that occur in bodily function that occur during a panic attack (eg. a change in HR) with the full-blown panic attack – ‘interoceptive conditioning’ (Bouton et al. 2001), and often misinterpret small changes in body function which can exacerbate symptoms
- Reduced symptoms in having a ‘safe person’ nearby – show that symptoms of panic become associated with certain situations, and that operant behaviours such as sticking close to a ‘safe person’ can be reinforced by the reduction of panic symptoms
Describe anticipatory nausea and vomiting
- Chemotherapy (US) produces nausea (UR)
- In addition to the effects of the drugs, the clinic can come to elicit ANV (Boakes et al. 1993)
- Evidence that it is conditioned:
a) Only develops in those that have had at least one chemotherapy session (Stockhorts et al. 1998)
b) Severity of ANV related to severity of initial reaction to drugs
Describe white coat effect
- People provide higher BP readings when taken in the GP’s office than when taken at home, suggesting that observations and measurements in the clinic are inherently biased
Describe how classical conditioning can explain the placebo effect
- Classical conditioning has been most used to analyse the placebo effect, even though it is known that other learning paradigms are likely to be important too.
- General premise is that conditioning underlies the acquisition of expectancies, which in turn mediate placebo effects – positive effect (placebo) produced by anticipatory cues for alleviation of symptoms, negative effect (nocebo) produced by negative consequences of anticipated failure
- Kirsch (1997) investigated expectancy theory of placebo responses:
Provided participants with information intended to impede the formation of placebo expectancies during clinical trials whilst assessing placebo expectancies
Correlation analysed, and found that the placebo response was linked solely to the expectancy, and so conditioning produced the placebo effect through its effects on expectancies.
Critique would be error involved in measuring placebo expectancies - Placebo analgesia: endogenous opioid release (Benedetti et al 1999) and placebo response in Parkinsonism: DA release (Price, 2002); so for instance, exposure to a physical stimulus similar to a biologically-active medication enhances its effect
- Placebo effect changed amount of movement – Benedetti et al (2003): studied pain in healthy volunteers and motor control in PD patients, and two ‘unconscious’ physiological processes, GH and cortisol
- found that sumatriptan stimulates GH and inhibits cortisol
What are phobias?
- Type of anxiety disorder, persistent fear of an object/situation, typically disproportionate to the actual danger posed; acquired through learning from the environment (classical conditioning, operant conditioning, and social learning).
Describe the two process theory of phobias
Suggests there is an aquisition phase an a maintenance phase
Acquisition
could be direct (classical) such as a traumatic experience
could be social learning by observing fear in another (vicarious) Askew & Field (2007), or hearing about danger (verbal)
Maintenance
Operant conditioning – approaching phobic object/situation elicits conditioned anxiety response
Avoidance reduces anxiety, so a negative reinforcer meaning that patient more likely to continue avoidance behaviour
How might it be possible to overcome phobias?
- Therefore learning theory suggests that phobias should be traceable to an original learning experience and therefore should be possible to ‘decondition’ phobias using CBT
Describe Andrew and Field experiment
- Askew & Field (2007) showed children (7-9 yrs old) pictures of novel animals paired with either scared, happy or no facial expressions.
Consequently these children took significantly longer to approach a box that they believed to contain a ‘scared face’ paired animal, with these beliefs persisting up to 3 months.
Study supports that vicarious learning has a role in fear acquisition
Critique that they are measuring fear, not technically phobia development
Describe medical avoidance
DSM-IV acknowledges needle and dental phobias as specific types of phobia, related specifically to the medical context
- Arises from conditioning in which some initially-neutral stimuli (dentist chair, needle, sound of drill or smells of room) become associated with pain (De Jongh et al. 1995); evidence for this:
a) Dental phobia is found to be related to the amount of pain experienced
b) More likely to occur in patients having had no previous experience
c) May be like other phobias but, with ANV, the clinic itself is the stimulus rather than eg. needle
Describe OCD
- Obsessions – classical conditioning produces associations between unrelated stimuli, producing anxiety. Over time the learned fears can generalize to more specific stimuli (eg. turning off taps to checking all of bathroom)
- Compulsions – operant conditioning as the individual attempts to reduce the anxiety by avoidance and performance of compulsions perpetuating a vicious cycle
- Learning theory does not account for all aspects of OCD, for example why some compulsions persist even when the produce rather than reduce anxiety. And why some cases of traumatic brain injury can result in OCD as no triggering event.
Describe conditioning in drug addiction
- As well as obvious pharmacological/physiological dependence there is also thought to be a psychological element to drug addiction.
- Dependent on the drug in question, the types of conditioning are involved to different extents, and in both the drug’s effects act as the rewarding stimulus:
Classical conditioning – described previously (Seigel 1977) but neutral objects can become cues for addiction
Operant – the behaviour of preparing/administering becomes reinforced
Describe Seigel 1977 experiment
- An example of direct conditioning – people (and experimental models such as rats) develop a tolerance to morphine which manifests itself as an ability to withstand higher dosages.
- Seigel (1977) postulated morphine tolerance was a conditioned response to conditioned drug stimuli
Conditioned rats to morphine administration where CS was a green chamber (context), and UR was the physiological changes (e.g. change in body temp and blood flow that occurred)
A cue that comes to predict these changes acts to counteract them (like saliva counteracts mouth-drying effect of food)
Repeated trials increasing drug dose until large tolerance achieved – a large dose can be tolerated because the animal learns that the context signals an increased likelihood of drug
Then ½ rats moved to a red chamber (context changed) and given same previously tolerated dose but they died as the correct responses were not elicited.
Control was other ½ of rats still in green chamber and survived.
Supported that tolerance is not simply a biochemical or physiological change in synaptic efficacy/downregulation of receptors.
Provides some evidence for the efficacy of rehab facilities in halting of addiction, but as patients return home to the addiction-cued environment then relapse is common - Applications of classical conditioning – aversive conditioning of alcoholics through use of Disulfiram which blocks ethanol breakdown by inhibiting acetaldehyde dehydrogenase to cause an unpleasant reaction when alcohol is consumed.
Describe learning in schizophrenia
- Schizophrenics exhibit increased associativity - “associate anything with everything”
- (This is because the brain’s ability to select in relation to validity/saliency is impaired)
- Results in biased social thinking and attention - paranoia
- Schizophrenics show weak (Kamin’s) blocking effect - see notes
-
Intro to psych19
-
Human attention38
-
Human memory45
-
Communication: producing and understanding language43
-
Anxiety disorders and psychological therapies21
-
Cognitive disorders of old age27
-
Eating disorders50
-
Normal and abnormal development32
-
Adolescent psychopathology18
-
Psychological aspects of medical practice13
-
Mood disorders30
-
Learning and conditioning23
