Blakemoor and Cooper: Brain Plasticity (Biological)) Flashcards
What theories was Blakemoor and Cooper’s study based on?
-That cat intelligence is the capacity of the domesticated cat to learn, solve problems and adapt to its environment
-The physical structure of human and cat brains is very similar: both have cerebral cortices with similar lobes, have a surface folding, and grey and white matter
-The thalamus of a cat and additional secondary nuclear structures are responsible for controlling impulses to the cortex, functions of sleep, memory originally formed of sensory data and other cellular functioning
-Kittens brains have a neuroplasticity
-In a normal cat, neurones of the visual cortex are selective for the orientation of lines an edges in the visual field and the preferred orientations of different cells are distributed all around the clock
What was the background to Blakemoor and Cooper’s study?
-Research found that early visual experience can change neural organisation in kittens. When kitten were reared with one eye viewing vertical stripes and the other horizontal, they found that out of 21 neurones with elongated receptive fields all were monocularly drive and in all but one case the orientation of the receptive field closely matched the pattern experienced by that eye.
What was the aim of Blakemoor and Cooper’s study?
To investigate the development of the primary visual cortex in cats and to find out if some of its properties such as orientation selectively are innate or learned. They looked at binocular vision instead of monocular vision meaning both eyes were used together.
What was the research method of Blakemoor and Cooper’s study?
Lab experiment with an independent measures design
What was the IV and the DV in Blakemoor and Cooper’s study?
The IV was whether the kittens were reared in a horizontal or a vertical environment
The DV was their visumotor behaviour once they were placed in an illuminated environment
What was the sample of Blakemoor and Cooper’s study?
-Kittens were randomly allocated to one of the two conditions
-Two of the kittens (one from each condition) were used to study neurophysical effects
What was the procedure in Blakemoor and Cooper’s study?
-Housed from birth in a completely dark room
-From the age of two weeks, they were put into a special apparatus for an average of about five hours per day. It had a clear glass platform inside a tall cylinder the entire inner surface of which was covered with high contrast blakc and white stripes, either vertical or horizontal. There were no edges and the kitten wore a wide black collar
-This routine was stopped when the kittens were 5 months old
-The kittens were then taken for several hours each week from their dark cage to a small well lit room, furnished with tables and chairs
-Visual reactions were noted
-At 7.5 months, 2 of the kittens were anaesthetised so their neurophysiology could be examined.
What behaviour was observed of the kittens in Blakemoor and Cooper’s study?
They were initially extremely visually impaired:
-Their papillary reflexes were normal but they showed no visual placing when brought up to a table top and no startle response when an object was thrust towards them
-They guided themselves mainly by touch
-They were frightened when they reached the edge of the surface they were standing on
-They showed ‘behavioural blindness’ in that the kittens raised in the horizontal environment could not detect vertically aligned objects and vice versa
-Only the eyes of the kitten brought up in vertical stripes followed a rode held vertically and only the eyes of the kitten reared in horizontal stripes followed the rod if it was held horizontally
How long did the behaviours of the kittens last in Blakemoor and Cooper’s study?
-The kittens quickly recovered from many of the deficiencies and within a total of about 10 hours of normal vision they showed startled responses and visual placing and would jump with ease from a chair to the floor.
-However some defects were permanent. They always followed moving objects with very clumsy, jerky head movements and they often tried to touch things moving on the other side of the room, well beyond their reach. They also wouldn’t respond to items of an opposite orientation to the one they were reared in.
What did the neurophysiological examination show in Blakemoor and Cooper’s study?
-No evidence of severe astigmatism
-Horizontal plane recognition cells did not fire off in the kitten from the vertical environment and vice versa
-About 75% of cells in both cats were clearly binocular and in almost every way the responses were like that of a normal kitten
-Distribution of preferred orientations were totally abnormal: not one neurone had its optical orientation within 20 degrees of the appropriate axis
-No obvious large regions of ‘silent’ cortex corresponding to the missing cortical columns were observed/found
What possible conclusions can be drawn from Blakemoor and Cooper’s study?
-Visual experiences in the early life of kittens can modify their brains and have profound perceptual consequences
-A kitten’s visual cortex may adjust itself during maturation to the nature of its visual experience
-Nervous system adapts to match the probability of occurrence of features of its visual input
-Brain development is determined by the functional demands made upon it, rather than pre-programmed genetic factors
-The environment can determine perception at both a behavioural and physiological level
What are the strengths and weaknesses of the research method used in Blakemoor and Cooper’s study?
Highly controlled and they were able to conclude that its was the type of environment in which the kittens were raised that caused the kittens’ observed perceptual difficulties so it had internal validity
What are the strengths are weaknesses of the type of data collected in Blakemoor and Cooper’s study?
-Quantitative data in terms of the neurobiological findings in their study. Of 125 neurones studied in two cats, all but one was shown to favour the restricted orientation in which the cats were raised. This gives scientific evidence of brain plasticity and allows research to be repeated and tested for reliability
-Qualitative describing the kittens’ reactions, for example the fact that they had no startle response and bumped into things around the room. Provides descriptive examples of the differences observed in the kittens in the two different environments
What ethical considerations are there for Blakemoor and Cooper’s study?
-Would have suffered some pain and distress from the invasive physiological procedures. They may have also been distressed by being separated from their mother.
-It was noted that the kittens didn’t seem to be upset by the monotony of their surroundings.
-No fewer kittens could have been used
-There was low certainty of medical benefit
-It was however conducted within the strict ethical guidelines laid down by the Home Office for studies conducted on animals
What was the validity like for Blakemoor and Cooper’s study?
There was a high level of control so there was good internal validity. Both behavioural and neurophysiological measures were used meaning the study had concurrent reliability.
