Blakemore and Cooper (1970): biological
Background
Neuroplasticity- brains can change in response to external stimuli. Hippocampi- important for memory.
They conducted a study into the effect of the environment on the brain in cats
Aim
To limit the visual experience of kittens to one orientation- vertical or horizontal stripes- and to compare the behavioural consequences of this restricted visual environment on the kittens.
Also aimed to investigate the neurophysiological effects on the neurons in the kittens brain.
Method
Lab experiment
Controls
Horizontal or vertical environment in which the kittens were strictly controlled. Kittens were allocated to a condition randomly
Apparatus
Stood on a clear glass platform, inside a tall cylinder, a lid was placed on the cylinder and the stripes were a variety of lengths
Design
Independent measures
Sample
Kittens for birth to approx. 1 year old
Procedure
From birth, the kittens were housed in a completely dark room. At two weeks of age, the kittens were randomly placed in one of the two conditions for 5 hours a day.
After 5 months, exposure to the experimental conditions ended and the kittens were then placed for several hours a week from their small dark room, to a small, well lit furnished room. The DV was then measured- whether kittens raised in a horizontal environment could detect vertically aligned objects.
Variables
IV: Horizontal or vertical environment
DV: whether kittens raised in a horizontal environment could direct vertically aligned objects and vise-versa
After 7.5 months, two kittens, one from each condition were anaesthetised and their neurophysiology was examined.
Results
Conclusions
Brain development is clearly affected by early experiences and environmental factors rather than just genetics.
Behavioural findings: All the kittens were visually impaired; they demonstrated no visual placing when brought up to a table top and had no startle response when an object was thrown towards them. However their pupillary reflexes were normal and they guided themselves around the room by touch.
Neurophysiological findings: evidence that horizontal plane recognition task did not 'fire off' in the kitten from the vertical environment- kittens were unable to perform orientation selectively and therefore suffered from 'physical blindness'
All kittens showed behaviour blindness, meaning they could not detect objects of contours that were aligned in the opposite way to their previous environment. There was a recovery of some deficiencies from their early deprivation- visual placement, startled responses. Permanent damage- trying to touch beyond reach.