Post by TheWeeMan on May 3, 2004 12:24:18 GMT 1
A guest has asked that I post stuff on Blakemore and Cooper (1970). Hope this is useful and maybe prompts a post or two?
(For PC.)
Blakemore, C. & Cooper, G.F. (1970). Development of the brain depends on the visual environment. Nature, 228, 447-448.
Aim:To investigate the development of the primary visual cortex, and to find out if some of its properties such as orientation selectivity were innate (as suggested by Hubel and Wiesel in 1963) or learned.
Method/Procedure: Laboratory experiment. Independent group design. Blakemore & Cooper (1970) randomly allocated and raised 2-week-old kittens in either a horizontal or vertical striped environment for 5 hours per day for five months. For the rest of their day the kittens were in darkness!
The two conditions of the independent variables were the environments within which the kittens were raised. The environments were either a drum with vertical stripes, or a drum with horizontal stripes. While in their respective drums the kittens wore cardboard collars, which enabled them only to look forwards.
The dependent variable was whether the horizontally raised kitten could detect vertically aligned objects, and/or if the vertically raised kittens could detect horizontally aligned objects.
‘The kittens did not seem upset by the monotony of their surroundings and they sat for long periods inspecting the walls of the tube.’ (Blakemore and Cooper, 1970).
Results: At five months the kittens were tested for line recognition. They showed ‘behavioural blindness’ in that those raised in horizontal environment could not detect vertically aligned objects, and vice-versa. Only the eyes of the cat brought up on vertical stripes followed a rod held vertically and shaken. They remained blind to contours perpendicular to the stripes they had lived with. The same thing was found with the horizontal cats. When microelectrodes were later placed into individual cells in their visual cortex, Blakemore and Cooper found that horizontal plane recognition cells did not ‘fire-off’ in those kittens from the vertical environment, and vertical plane recognition cells did not ‘fire-off’ in those kittens from the horizontal environment. They thus also suffered from ‘physiological blindness’.
Conclusions: Development of the visual cortex continues well after infancy, and that both before and after birth brain development is determined by the functional demands on the brain, (what it is called upon to do and deal with) rather than by preprogrammed genetic factors. The study strongly suggests that environment can determine perception at both a behavioural and physiological level: at least in cats.
(For PC.)
Blakemore, C. & Cooper, G.F. (1970). Development of the brain depends on the visual environment. Nature, 228, 447-448.
Aim:To investigate the development of the primary visual cortex, and to find out if some of its properties such as orientation selectivity were innate (as suggested by Hubel and Wiesel in 1963) or learned.
Method/Procedure: Laboratory experiment. Independent group design. Blakemore & Cooper (1970) randomly allocated and raised 2-week-old kittens in either a horizontal or vertical striped environment for 5 hours per day for five months. For the rest of their day the kittens were in darkness!
The two conditions of the independent variables were the environments within which the kittens were raised. The environments were either a drum with vertical stripes, or a drum with horizontal stripes. While in their respective drums the kittens wore cardboard collars, which enabled them only to look forwards.
The dependent variable was whether the horizontally raised kitten could detect vertically aligned objects, and/or if the vertically raised kittens could detect horizontally aligned objects.
‘The kittens did not seem upset by the monotony of their surroundings and they sat for long periods inspecting the walls of the tube.’ (Blakemore and Cooper, 1970).
Results: At five months the kittens were tested for line recognition. They showed ‘behavioural blindness’ in that those raised in horizontal environment could not detect vertically aligned objects, and vice-versa. Only the eyes of the cat brought up on vertical stripes followed a rod held vertically and shaken. They remained blind to contours perpendicular to the stripes they had lived with. The same thing was found with the horizontal cats. When microelectrodes were later placed into individual cells in their visual cortex, Blakemore and Cooper found that horizontal plane recognition cells did not ‘fire-off’ in those kittens from the vertical environment, and vertical plane recognition cells did not ‘fire-off’ in those kittens from the horizontal environment. They thus also suffered from ‘physiological blindness’.
Conclusions: Development of the visual cortex continues well after infancy, and that both before and after birth brain development is determined by the functional demands on the brain, (what it is called upon to do and deal with) rather than by preprogrammed genetic factors. The study strongly suggests that environment can determine perception at both a behavioural and physiological level: at least in cats.