Blakemore and Cooper

Blakemore and Cooper

1. Method

   • Laboratory experiment
   • Independent measures

2. Aim

   • Look at the influence of early visual experience on the development of the visual system in kittens

3. Participants

   • Kittens
   • Birth to one year old
   • 2 kittens used to study neurophysical effects

4. Procedure

   • Kittens were kept in completely dark rooms from birth
   • From 2 weeks old the kittens visual experience was manipulated
     • Placed in a cylinder with a glass floor
     • Vertical or horizontal stripes
     • 5 hours per day
     • Wore wide black collars so they couldn't see their body
   • Stopped when 5 months old
     • Taken into a normal room a few hours a week
     • Visual reactions observed
   • At 7.5 months old 2 kittens were anaesthetised so their neurophysiology could be examined

5. Results

   • Behavioural
     • Extremely visually impaired
       • Pupillary reflexes were normal
       • No startle response
       • No visual placing
       • Navigated mainly by touch
       • Frightened when they reached the edge of a surface
     • Showed behavioural blindness
       • Only detect objects of the orientation they were raised in
     • After about 10 hours most effects were reversed
       • Still had clumsy jerky head movements
       • Tried to touch things well out of their reach
   • Neurophysiological
     • Showed physical blindness
       • Neurons only fired off for the orientation they were raised in
     • Distribution of preferred orientation cells was abnormal
     • All but 1 out of 125 neurons showed favour to restricted oreintation

6. Conclutions

   • Early visual experiences can modify the brain and have perceptual consequences
   • Nervous system adapts to the most likely visual input
   • Brain development is determined by the demands of the environment

7. Evaluation

   • Validity
     • Low ecological validity
     • High design validity
       • Clear cause and effect
     • Concurrent Validity
       • Behavioural and neurophysiological tests supported eachother
   • Reliability
     • Could easily be replicated to test reliability
     • Larger sample needed to establish consistency
   • Ethics
     • Complied with strict ethical guidelines
     • Raises questions about the ethics of animal research
   • Data
     • Quantitative
       • Scientific evidence
       • Easily test for relaibility
     • Qualitative
       • Provided detailed examples of difference
   • Sample
     • Small
       • Cannot generalise to all cats
     • Used cats
       • Cannot generalise to humans
   • Ethnocentrism
     • Studied cats so not relevent
   • Research Method
     • Highly controlled
       • Establish cause and effect

8. Links to area/perspective

   • Biological
     • Effect of environment on brain development
     • Brain plasticity

9. Links to key theme

   • In cats developing brains the visual neurons will change their preferred orientation
   • Only develop vision for environment they are raised in

10. Links to debates

    • Nature/Nurture
      • Nature provided the neurons with a preferred oreintation
      • Nurture had an effect on the development of their visual orientation
    • Psychology as a science
      • Fulfills scientific criteria
      • Falsifiable