Animal Learning Classical Conditioning

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Animal Learning- Classical Conditioning

• Keith Clements
• Animal Cognition

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Aims

• Students should be able to
• Describe the basic features of classical
  conditioning
• Describe variations to the basic procedure, such
  as inhibitory conditioning, sensory
  preconditioning and blocking and their
  implications.
• Appreciate how, and why, biological constraints
  may affect conditioning.

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Classical Conditioning

• You need to be familiar with the basic
  terminology
• US, CS, UR, CR
• Extinction
• Discrimination and generalization
• Excitation and Inhibition
• Pavlov viewed extinction as involving active
  inhibition of the response, because extinguished
  responses show spontaneous recovery
• Conditioning can also produce inhibitory links.

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Producing a conditioned inhibitor

• Acquisition
• Tone Food
• Tone Light No Food
• Testing
• Tone Salivation
• CS CR
• Light No response
• CS-

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Inhibitory conditioning

• How would we know it had worked?
• A Summation test. A conditioned inhibitor will
  inhibit responding to a second CS paired with
  it.
• A retardation test can also be used, If a
  stimulus is a conditioned inhibitor it will take
  longer for it to acquire excitatory properties,
  when it is paired with a US, than would be the
  case if it was initially a neutral stimulus.
• Inhibitory conditioning is one line of evidence
  against stimulus-response accounts of classical
  conditioning

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Second-order conditioning

• The response transferred to a CS may subsequently
  be transferred to another neutral stimulus.
• This occurs in second-order conditioning.
• The reverse procedure is known as sensory
  pre-conditioning. This shows that classical
  conditioning can occur without an apparent change
  in behaviour.

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Sensory preconditioning

• Rizley Rescorla (1972)
• Rats were presented with several trials in which
  a light was followed by a tone.
• Subsequently the tone was used as a signal for
  shock.
• The second Sniffy practical examines one way of
  measuring the conditioned response in this sort
  of study
• As expected the tone produced a conditioned
  response because of its association with shock.
• When the light was presented alone it also
  produced a CR

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Contiguity or contingency?

• Pavlov assumed contiguity between CS US was
  sufficient for conditioning to occur
• Evidence shows that only if the CS reliably
  predicts the occurrence of the US will
  conditioning occur. Varying the correlation
  between the CS and US alters the strength of
  conditioning.

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CS-US correlation and strength of responding

• Rescorla (1968) varied the correlation between CS
  and US by delivering the US on its own between
  trials.
• The strength of the CR was assessed using a
  conditioned emotional response paradigm. CS's
  associated with aversive stimuli inhibit operant
  responding.
• The strength of the CR was sensitive to the
  relative probabilities of the US when the CS was
  present and when it was not.

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Blocking

• Shows that conditioning occurs to a given
  stimulus to the extent that the stimulus adds to
  an individuals' ability to predict the occurrence
  of important events.
• If a conditioned stimulus already predicts a
  given US, further learning is blocked.

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Blocking ( Kamin, 1968)
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Biological influences

• The nature of the stimuli can influence the
  development of conditioning.
• Learned taste-Aversion (Garcia Koelling, 1966)
  demonstrates that tastes are readily associated
  with nausea, allowing conditioning to occur after
  a single exposure and with very long
  inter-stimulus intervals.

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Taste Aversion

• Acquisition
• Saccharin-flavoured water
• Tone Lithium Chloride Nausea
• Light
• Testing
• Saccharin flavour Disgust (is avoided)
• Tone Light No conditioned response
• (Do not suppress drinking)

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Applications

• Classical conditioning and emotional responses.
• Phobias may be viewed as learned fear responses.
  Such learning appears to be particularly common
  in relation to biologically significant stimuli.
  Seligman (1972) suggests that such stimuli may be
  evolutionarily prepared to take part in fear
  conditioning.
• Exposure-based therapies (such as systematic
  desensitization) aim to extinguish such
  maladaptive conditioned responses.

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Recommended Reading

• References from the first learning session cover
  classical conditioning
• Essential Reading
• Wynne (2001) Animal Cognition, Chapter 3
• Further Reading
• Klein, S.B. (2002). Learning Principles and
  Applications (4th Ed.). New York McGraw Hill.
• Morgan, D.L. (2002) Essentials of Learning
  Cognition. Boston McGraw-Hill
• Schwartz, B. Robbins, S.J. (1995). Psychology
  of learning and behaviour ( 4th ed). New York
  Norton.
• Web Sites
• Bjorn Brembs' web site includes a description of
  classical and Operant conditioning
  www.brembs.net/, select I from the menu.
• Dr. Robert Cook's pages include information
  about Pavlov, Thorndike and Skinner at
  www.pigeon.psy.tufts.edu/psych26/history.htm.

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