Animal Learning

• Darwin - Origin of Species and natural selection


  1859
• Natural selection


  • Variability among individuals within a population
  • Variability is hereditary
  • More offspring are born than can survive
  • Competition for resources
  • Survivors able to reproduce
• Studying animals is an issue because they are unlike humans, they do not have language, and we cannot research their cognition or internal processes
• Anthropomorphism


  Seeing animal behaviour as the result of human-like internal thought processes
• Lloyd Morgan's Canon


  We should not hypothesis a more complex hypothesis without cancelling out simple ones first
• Thorndike's Law of Effect


  If a response leads to a satisfying outcome, it will be strengthened
• Operant/Instrumental Conditioning


  1. Conditioning chamber/Skinner box

  2. Instrumental conditioning requires a response to a stimulus which provides an outcome (reinforcer) that is of biological importance to the specimen
• Response shaping


  To create required responses, small approximations of the desired behaviour is rewarded. Without this, arbitrary behaviours could lead to the dispensing of food.
• Schedules of reinforcement


  • Fixed ratio (reward after a certain amount of responses, gig economy)
  • Fixed interval (reward after a set amount of time)
  • Variable ratio (reward after a random amount of responses, gambling)
  • Variable interval (reward after a random amount of time, social media)
• Stimulus generalisation


  Similar response on a generalisation gradient, correlating with how closely the stimuli resembles the original stimuli.
• Ranking 'Animal Intelligence' - Aristotle's Great Chain of Being considering legs and amount of blood, Nakajima (2002) - students asked to rank animal intelligence
• Evolution is not linear and species are not 'more evolved' than others. Impossible to organise intelligence in a linear scale.
• Cephalization index


  K = E/P^(2/3), where E is brain weight and P is body weight
• Larger brains require more % of the brain for motor control
• Macphail (1982) - null hypothesis that all species have the same level of intelligence, it just depends on how we express it, except humans who have language and other forms of intelligence
• Learning


  A relatively permanent change in behaviour resulting from experience
• Between-species differences in speed of learning - Skard (1950) rats quicker and more accurate than humans in a complex maze, Warren (1965) different species can't have the same conditions, Angermeier (1984) smaller animals better at operant response
• Within-species differences in speed of learning - Garcia and Koelling (1966) stimuli more readily associated when its flavour/illness vs light and tone/shock
• Intelligence


  Not a useful term because it is related to the concept of IQ, which can't be generalised to humans. Cognition is a better term as it doesn't get confused with reasoning and is thought of as the ability to process information in an adaptive way
• Animal intelligence more commonly examined through how species have adapted to better suit their environment
• Animal memory


  When current behaviour is under the influence of past experience
• Clark's nutcracker storing ~30,000 seeds in ~4000 caches are more successful in finding their own caches compared to accidentally finding someone else's
• Pigeons learnt to respond to certain images with squiggles, being able to discriminate from 160, repeated with everyday images where they could discriminate from 320 photos
• Mice given 19 or 29h day-light cycles struggled to anticipate food, indicating they worked on a 24h cycle
• Cockroaches adjusted to ~23.5h day cycle, and when their eyes were uncovered they regained the 24h pattern 1h per day, showing how any discrepancy in circadian rhythms is modulated by external cues
• Rats pressing different levers for tone 2s long and 16s long, can discriminate length and time
• Rats pressing lever after lights had been turned off for 4s
• Rats pressing lever for certain amount of tones (4 or 16), could have been time, but they could distinguish even if time was the same
• 3 rhesus monkeys pressing blocks on screen in order with varying surface area and variables
• Five-day-old chicks always went to food well number they had been trained
• Alex the parrot could announce colour or number of objects shown, could have been subitising
• Pigeons able to associate certain objects and people in pictures, and able to identify oak leaves from new exemplars, even from 1 training image
• Explanations for categorisation


  • Innate categories
  • Exemplar learning
  • Feature learning
  • Exemplar learning and stimulus generalisation
• Habituation


  Reduction in responsiveness to a stimulus due to repeated presentations
• Wagner's model of stimulus processing

  Memories or representations can be held in 1 of 3 stores - A1 (ST) → A2 (rehearsal) ↔ I (LT)
• Rats avoided unvisited arm in radial arm maze, can remember 8-17 arms for up to 4 hours due to landmarks
• Rats unable to find retroactive interference in radial arm maze, less accurate after 3 mazes
• Consolidation


  Combination of neurons activated when first presented and when shown again
• Rats given ECS shock 1m after couldn't remember, but 30m after could remember
• Holloway and Domjan (1993)

  Male quail birds learnt to associate a light with approaching a receptive female. This could be a S-R relationship with the stimulus being the light, the response being the approach, and the reinforcer being the receptive female, or it could be a S-S relationship, where the light reminds the male that the female is there