Blakemore & Cooper (1970) Flashcards
Background of the study
-B&C inspired by Hirsch and Spinelli, they were interested in the neurons in the visual cortex of the brain
-Found they could change the way the visual neurons in the visual cortex aligned themselves by controlling what the kittens could do as they grew up
-Kittens were raised so they could only see vertical stripes in one eyes, and horizontal in the other
-When the cats were release into an everyday environment, researchers found they had visual impairments
Brain plasticity
Your brain adapts and changes according to what you do in your life
Visual cortex (and visual neurons)
The part of the brain that receives and processes the sensory nerve impulses from the eyes
Startle responses
The ‘backing off’ reaction of a cat when an object is moved quickly towards their face
Visual placing
When a cat puts its feet out to meet the edge pf a surface
Overall aims of the study
-To investigate how being raised in a visually restrictive environment would affect the visual brain development of cats
>Compare the behavioural consequences of raising kittens seeing only horizontal or vertical stripes
>Investigate the neurophysiological effect on neurons in the kittens visual cortex (brain plasticity)
Sample
-Two kittens
-Birth until approximately one years old
What was the environment for the first two weeks of the kittens life?
-They were kept in a completely dark room
What was the environment from two weeks until five months?
-Put in a striped cylinder for five hours a day
-They wore a black collar so were able to see horizontal/vertical stripes
-Were back in complete darkness for the rest of the day
What happened to the kittens when they were five months old?
-The kitten was taken into a well lit room with furniture to test their behaviour
What was the IV in the study?
-The orientation of stripes within the cylinder
-Either horizontal or vertical
What was the experimental design?
-Each kitten was exposed to a different striped cylinder
-Independent measures
What were controls used in the study?
-Five hours in the cylinder
-Same amount of time in the dark
-Wore the black collar
Behavioural findings
-Navigated around the room by touch
-Were generally clumsy
-Had normal pupillary reflexes
-Had no startle reflexes
-Had no visual placing
After 10 hours exposure to typical surroundings, what deficits did the cats quickly recover from?
-Visual placing returned to normal
-Startle response returned to normal
After 10 hours exposure to typical surroundings, what deficits remained?
-Still clumsy in following moving objects
-Still bumped into objects/furniture
How did the horizontally and vertically raised cats differ?
-B&C described the cats as ‘virtually blind to the opposite orientation of their upbringing
-Found this by experimenters shaking a rod in front of the cat and seeing the response.
>They found the cat only responded if the rod was shaken in the same orientation as they had seen in the cylinder, similar results found when a striped perspex sheet used
Neurophysiological test
-Cats anaesthetised and assessed on how neurons responded to seeing light at horizontal/vertical orientations
-Done by inserting electrodes into the primary visual cortex
Neurophysiological results
-Scans showed that the visual neurons within the visual cortex had aligned themselves to match the environment the kitten was bought up in.
-There were little to no neurons aligned to the opposite direction
-This is because the cats has no need for neurons in the other direction, and therefore were moved elsewhere
Type of data collected for behavioural findings
-Qualitative
-Descriptions of defecits shown by the cats
Type of data collected for neurophysiological findings
-Quantitative
-Based on the alignment of the visual neurons from the visual cortex scan
Conclusions
The difference between the kittens suggest that the neurons can change the preferred orientation according to the stimulation they receive, matching the ability of the brain to respond to the features in its visual input
In what ways can this study be defended in relation to ethics?
-Replacement-no alternative replacement to animals within this research
-Reduction-they reduced the impact to the minimum amount of cats (2)
-Refinement-they refined the procedure by having the cat in the cylinder for 5 hours a day
In what ways can this study be criticised in relation to ethics?
-There are not many practical applications of the research, and therefore was perhaps not worth harming the kittens for
Why is it not appropriate to discuss ethnocentrism in relation to the study?
-It isn’t relevant
-Looking at biological factors
-The environment the kittens were in was not culturally biased
Internal reliability
-Procedure was highly standardised and replicable, due to the high level of controls
External reliability
-Only two kittens were used in the study
-Likely doesn’t matter as investigating biological concepts
Internal validity
-Seemed to be a good test of brain plasticity
-Only difference in procedure was the orientation of the stripes for each kitten
Population validity
Possible problem with generalising beyond the species of kitten
Concurrent validity
Cats showed the same deficits in two separate tests to check their perception of the other orientation
Ecological validity
-Not a realistic scenario as the environment was so visually restricted
-This doesn’t happen in real life
What debates does this study link to?
-Nature/nurture
-Ethical considerations
-Psychology as a science
-Individual/situational
-Usefulness
Nature/nurture
-Nurture
-Brains can change in response to the visual environment
Psychology as a science
-Replicable, objective and falsifiable
-Very controlled, used quantitative measures and can be replicated to see if it is false
Individual/situational
Behaviour dependent on situation of cylinder orientation
Usefulness
Not really useful at all