Blakemore and Cooper

• Aim


  • To investigate the physiological and behavioural effects of a limited visual experience
  • Whether brain plasticity occurs due to experiences rather than nature
• Sample


  • New born kittens who were immediately placed ino a dark room
  • At 2 weeks of age, the kittens were then randomly placed into one of the 2 conditions for 5 hours a day
• Method


  • Lab experiment
  • IV = horizontal or vertical environment
  • DV = Whether kittens raised in each environment could detect objects in the opposite orientation to that which they were reared in

  Procedure

  • Kittens stood on a clear glass platform inside a tall cylinder covered in either horizontal or vertical black-and-white stripes
  • Visual field was restricted to 130 degrees
  • After 5 months, the kittens were introduced to a small, well-lit, furnished room
  • After 7 1/2 months, 2 (one from each condition) were anaesthetised and their neurophysiology was examined
• Results


  • All kittens were extremely visually impaired
  • They demonstrated no visual placing when put on a table top
  • No startle response when an object was thrust towards them
  • Papillary reflexes were norma and they guided themselves mainly by touch
  • Could not detect objects that were aligned in the opposite orientation to that which they were reared in
  • They showed fear when standing on the edge of a surface
  • The kittens did recover after 10 hours
  • Neurophysiological exam showed a less active visual cortex in the orientation opposite to the one that they were raised in
• Conclusion


  • Brain development is affected by early experiences and environmental factors rather than just genetics
  • There is clear evidence of brain plasticity
  • The visual experience of the kittens had modified their visual cortex
• Background


  Hirsch and Spinelli

  • Early visual experiences can change neuronal organisation in kittens
  • They were reared wearing special goggles that made one eye view vertical stripes only, and the other seeing horizontal stripes

  Visual tracking = The ability to follow the path of a moving objectDepth perception = The ability to judge the position of an object to establish how far away it is
• Link to the key theme

  Brain plasticity

  • The ability to change the size and shape of the brain
  • Human hippocampus has the ability to generate new cells throughout life

  Blakemore & Cooper

  • Investigated whether kittens raised in an environment of vertical or horizontal stripes would develop normal vision
  • It focused on how early life affected the brain
  • At first, the kittens guided themselves by touch and showed behavioural blindness
  • This proves that visual experiences in the early life of kittens can modify their brains and have perceptual consequences
• Link to key area

  Biological area

  • Explains human behaviour through an understandng of biological and neurological processes
  • Assumes that all behaviour has biological basis, meaning all behaviour can be explained by our biology
  • Blakemore & Cooper
  • Investigated whether kittens raised in an environment of vertical or horizontal stripes would develop normal vision
  • At first, the kittens guided themselves by touch and showed behavioural blindness
  • Visual experiences in the early life of kittens can modify their brains and have perceptual consequences