Biological: Blakemore and Cooper

Question 1

theories / background

Answer 1

> structure of brain in humans and cats is similar
kittens’ brains have a neuroplasticity
in a normal cat neurones of the visual cortex are selective for the orientation of lines and edges
early visual experience can change neural organisation

Question 2

aim

Answer 2

to investigate the development of the primary visual cortex and to find out if some of its properties are innate

Question 3

experimental method

Answer 3

lab

Question 4

experimental design

Answer 4

independent measures

Question 5

IV

Answer 5

if kitten raised in horizontal or vertical environment

Question 6

DV

Answer 6

visuomotor behaviour once placed in illuminated environment

Question 7

sample

Answer 7

> kittens randomly allocated to a condition
2 kittens used to study neurophysiology

Question 8

procedure

Answer 8

> raised in dark room
from 2 weeks- put in apparatus for 5 hours a day, stood on clear glass inside tall cylinder with either vertical or horizontal black and white stripes, no corners or edges
couldn’t see own body- wore a collar
stopped routine at 5 months
taken for several hours a week to small well lit room, furnished
visual reactions observed and noted
at 7.5 months 2 kittens were anaesthetised so neurophysiology could be examined

Question 9

results- visual impairment

Answer 9

> papillary reflexes normal but showed no visual placing, no startle response
guide themselves by touch
showed behavioural blindness- kittens in horizontal condition couldn’t detect vertical objects and vice versa
only eyes of vertical condition kittens followed vertical rod
kittens recovered quickly showing startle response and visual placing

Question 10

results- permanent effects

Answer 10

> follow moving objects with clumsy and jerky head movements
tried to touch things moving on other side of room

Question 11

results- neurophysiology

Answer 11

> no evidence of severe astigmatism
horizontal plane recognition cells didn’t fire off from vertical condition kitten and vice versa
75% of cells in both cat’s binocular
not one neurone had optimal orientation
no obvious large regions of ‘silent’ cortex

Question 12

conclusions

Answer 12

> visual experiences modify brains in early life
kittens visual cortex may adjust itself
nervous system adapts to match visual input
brain development determined by functional demands
environment can determine perception