Blakemore + Cooper

Question 1

key theme + area

Answer 1

• key theme = brain plasticity
• area = biological

Question 2

background

Answer 2

• Hubel + Wiesel (1962) - identified orientation-specific neurons - which are in the visual cortex which respond to lines which point in different directions
• (1970) total visual deprivation in kittens causes neurons in the brain in the associated eye to decline in number (especially between 4-8 weeks of age)

Question 3

aim

Answer 3

• to investigate the effect on kittens visual development of a restricted visual environment, consisting of either vertical stripes only or horizontal stripes only, in which the animal could move freely.

Question 4

research method

Answer 4

• lab experiment
• independent measures design
• IV = whether the kittens were reared in a horizontal or vertical environment
• DV = their visuomotor behaviour once placed in an illuminated environment

Question 5

sample

Answer 5

kittens from birth to 1yrs
randomly allocated to one of the two conditions
2 kittens (one vertical, one horizontal) were used to study neurophysiological effects

Question 6

procedure part 1

Answer 6

1. kittens were housed from birth in completely dark room
2. from aged 2 weeks put in special apparatus for around 5 hours per day
3. kitten stood on clear glass platform inside tall cylinder
4. inner surface covered with either vertical or horizontal black and white stripes varying in widths
5. wore wide black collar that restricted visual field to approx 130 degrees
6. stopped when 5 months

Question 7

procedure part 2

Answer 7

• kittens taken for several hours each week from dark cage to a small well lit room which is furnished
• visual reactions were observed + recorded
• at 7.5 months, the two kittens were anaesthetised so their neurophysiology could be examined

Question 8

types of findings

Answer 8

• behavioural
• neurophysiological

Question 9

behavioural findings

Answer 9

• regardless of conditions both were initially visually impaired
• pupillary reflexes normal but showed no visual placing
• guided mainly by touch
• frightened when reached edge of surface they’re on
• showed behavioural blindness
• kittens brought up in vertical condition followed vertical rod
• kittens brought up in horizontal condition followed horizontal rod
• kittens recovered within 10 hours

Question 10

behavioural findings

Answer 10

• some of their defects were permanent:
• They always followed moving objects with very clumsy, jerky head movements.
• They often tried to touch things moving on the other side of the room, well beyond their reach.

Question 11

neurophysiological findings

Answer 11

• Horizontal plane recognition cells did not ‘fire-off’ in the kitten from the vertical environment and vertical plane cells did not ‘fire-off’ in the kitten from the horizontal environment so there was distinct orientation selectivity, showing the kittens suffered from ‘physical blindness’.

Question 12

conclusion

Answer 12

• Visual experiences in the early life of kittens can modify their brains and have profound perceptual
  consequences.
• A kitten’s visual cortex may adjust to their experience.
• Preferred orientation changed depending on the
  environment- vertical vs horizontal lines.
• The environment can determine perception at both a behavioural and physiological level – at least in cats.