Psychology

• Behaviours selected by evolution

  • Reflexive: eye blinking, gripping
  • Instinctual: imprinting, migrating, homing
• Behaviours selected by experience

  • Learning: A relatively permanent change in behaviour as a result of experience
• Types of learning


  • Habituation
  • Classical conditioning
  • Instrumental conditioning
  • Observational learning
• Habituation


  The decline in the tendency to respond to a stimulus that has become familiar due to repeated exposure
• Habituation


  • Young turkeys show alarm to hawk shape but not goose shape - turkeys have habituated to the more frequent goose shape
• Classical conditioning


  Discovering that a neutral stimulus can become associated with an unconditioned stimulus to elicit a conditioned response
• Classical conditioning


  • NS = neutral stimulus
  • US = unconditioned stimulus
  • UR = unconditioned response
  • CS = conditioned stimulus
  • CR = conditioned response
• Classical conditioning


  US (puff of air) → UR (eye blink)

  2. NS (click) + US (air) → UR (eye blink)

  3. CS (click) → CR (eye blink)
• Conditioned emotional response


  Neutral stimuli (sounds, smells) associated with emotional events can elicit emotional responses
• Conditioned emotional response


  • Conditioned fear of rats in a child

  PTSD from battle sounds

  Dentist waiting room

  Advertising

  Fetishes
• Relation between UR and CR

  The UR and CR are similar but not the same - the CR is less intense and has fewer physiological components than the UR
• Compensatory reaction hypothesis


  The UR and CR can be opposites, as the body tries to compensate for the effects of the US
• Compensatory reaction hypothesis


  • Drugs producing a compensatory reaction - the same effect requires more of the drug because the system has been tilted the other way
• Drug administered without the compensatory reaction

  The same dose might be lethal because the body is unprepared
• Acquisition


  The process by which a conditioned stimulus becomes a conditioned response - how a NS becomes a CS
• Factors affecting acquisition


  • Number of NS and US pairings

  US intensity

  CS-US temporal relations
• Types of CS-US temporal relations

  Delayed (forward) conditioning

  2. Trace (forward) conditioning

  3. Simultaneous conditioning

  4. Backward conditioning
• Contingency


  The CS must be a reasonable predictor of the US for conditioning to occur
• Contingency


  The strength of the conditioned response depends on how often the CS accompanies the US, and how often the CS accompanies no US
• Extinction


  If the CS is repeatedly presented without the US, the CS will gradually decrease in eliciting the CR
• Spontaneous recovery


  After a period with no CS presentations, the CS may produce the CR again, although the revived CR is less intense
• Flooding


  Fear elicited by the CS (phobia) is eliminated by the process of extinction
• Stimulus generalisation


  A conditioned response formed to one conditioned stimulus will occur to other similar stimuli
• Stimulus discrimination


  Occurs when an organism does not respond to stimuli that are similar to those in training
• Generalisation gradients


  Continuous stimulus dimensions can produce generalisation gradients, where stimuli closer to the CS produce greater CRs
• Discrimination training


  Stimulus A is associated with the US and stimulus B isn't. If the subject discriminates, the CR occurs only with A
• Systematic desensitisation


  Treatment for phobias that combines extinction, stimulus generalisation and counter-conditioning
• Blocking


  Conditioning doesn't occur if a good predictor of the US already exists
• Higher order conditioning


  Once a stimulus has become an effective CS for a certain CR, that stimulus can be used to condition another stimulus
• Secondary preconditioning


  Learning occurs in the absence of the UR. Classical conditioning reveals the association already learnt between two events
• Stimuli's generalisation, higher order conditioning, and sensory pre-conditioning allow learning in one context to extend to a wider range of situations
• Stimulus discrimination and blocking limit the extent that learning in one context influences behaviour in other situations
• Biological constraints


  Associations between US and CS are more easily formed for biologically relevant stimuli
• Instrumental/operant conditioning


  Behaviours are strengthened or weakened based on their consequences, rather than a reflexive relation between stimulus and response
• Instrumental/operant conditioning


  • Positive consequences increase the likelihood of a response

  Negative consequences decrease the likelihood of a response

  The environment selects the "fittest" behaviours
• Acquisition in instrumental conditioning

  Behaviour is shaped by successive approximations towards the desired response
• If behaviours are followed by negative consequences


  The behaviours followed by release were strengthened while behaviours unrelated to release faded with time
• The environment selects


  The "fittest" behaviours
• Classical conditioning


  A relation between CS AND US
• The CS elicits


  The CR