Blakemore and Cooper Flashcards
Background into Blakemore and Cooper’s, 1970 study on early visual experience
The official cortex and plasticity
Hubble and weasel 1959, found that columns of cells in visual cortex respond to one particular orientation of a line e.g. 45°
Aim into Blakemore and Cooper’s, 1970 study on early visual experience
To investigate where the brain plasticity, because due to nature rather than nature.
 Design into Blakemore and Cooper’s, 1970 study on early visual experience
Lab experiment independent measures design
Iv kittens early experience was a horizontal or vertical environment
IV 1 behavioural
2 neurophysiological differences between cats
Sample into Blakemore and Cooper’s, 1970 study on early visual experience
Two. Newborn kittens at the beginning of the study, five months old during the behavioural test, and 7 1/2 months old for neurological test.
Materials/Apparatus
A special cylinder was constructed with no corners or edges
Procedure
Early experience
Kittens kept in completely dark room for two weeks
At two weeks old, the kittens were put in the cylinder (horizontal vertical environment) for an average of five hours a day otherwise they were kept in the dark room.
Exposure to normal environment
At five months, the visual deprivation stopped for several hours each week. The cats were taken to a small well lit room with chairs and tables. Cats were given artificial lenses to any visual difficulties were not due to astigmatism. (causes blurred vision.)
Testing
Behavioural assessment, cats responses to new visual world observed over the following weeks
Neurological assessment at 7 1/2 months, cats eyes were shown lines of all possible orientations around the clock and electrode was inserted in each neuron to measure electrical firing of the neuron.
Results
Behavioural assessment
Some of the cats reflexes were normal, e.g. eyes pupil contracted, normally in brighter light
Temporary deficit visual, placing reflex (cats, reach out with legs to nearby surface) not shown immediately after period of deprivation, but recovered within 10 hours.
Permanent deficit cats often reached out to touch something that was quite far away
Neurophysiological assessment
In both cats, 75% of sales will binocular and responded as a normal animal wood.
Responses to lines of certain orientations were completely abnormal e.g. in horizontal cats visual cortex cells did not respond to lines within 20° of vertical orientation and only 12 of 52 neurons responded within 45° of the vertical orientation. This direction dependence was significant .
Conclusion
Nature, the brain is modified by nurture experience of Line orientation, so that the biological system fits demands of the environment
Unused parts of the innate nervous system adapt to match the actual visual input experienced both demonstrate brain plasticity.
Research, methods and techniques
+ lab conditions mean extraneous variables can be controlled e.g. kittens first two weeks were in a completely dark room
-The artificial environment itself may act as an extremely variable. It may be that the distress caused by the experience affected the development of the kittens/cats. This means the effective visual deprivation observed in the study may not generalise to everyday experiences.
Validity
Validity supported by studies with humans. For example, some children are born with squint eyesight. If this is corrected with surgery before the age of four children develop normal binocular vision, but in older children the brain is permanently affected. This can be understood in terms of the cells in the visual cortex that change in response to early experience which are no longer plastic after a certain age.
Reliability
-there was no check on the reliability of the data. For example, it was not possible to see if another cat read with horizontal lines only would respond in the same way to vertical lines.
+ however, the fact that both cats responded and almost identical way to the orientation of their rearing suggests consistency
Sampling bias
Cats mammals and the visual systems are fairly similar to the human visual system as shown in brain scans. This research could not be done with human so it is necessary to use other animals in order to gain important insights about how the human visual system works.
Types of data
Quantitative data, e.g. reaction of the neurons to the orientation of the lines allowed comparisons between cats
Qualitative data, e.g. observations were made of the cats in a well lit environment, such as stripping over table legs
Ethical considerations
Blakemore and Cooper suggest that the kittens were not under distressed However, other research suggests that the kitten/cats might be affected by their visual and physical isolation.
