Blakemore and Cooper (1970)

Question 1

Background

Answer 1

In a normal cat, neurons of the visual cortex are selective for the orientation of lines and edges in the visual field, but early visual experience can change this orientation.

Question 2

Aim

Answer 2

To investigate the development of the primary visual cortex (in cats) and to find out if some of its properties such as orientation selectivity are innate (as suggested by Hubel and Wiesel) or learned.

Question 3

Sample

Answer 3

Kittens (studied from birth until this report was compiled) were randomly allocated to one of the two conditions.

Two of the kittens (one reared in a horizontal and one in a vertical environment) were used to study neurophysical effects.

Question 4

Procedure

Answer 4

This was a laboratory experiment which used an independent measures design.

The independent variable (IV) was: whether the kittens were reared in a horizontal or a vertical environment.

The dependent variable (DV) was their visuomotor behaviour once they were placed in an illuminated environment i.e. whether the horizontally raised kittens could detect vertically aligned objects and/or if the vertically raised kittens could detect horizontally aligned objects.

From the age of two weeks kittens were put into a special apparatus for an average of 5 hours per day which was a tall cylinder so all they could see was contrasting black and white stripes, either vertical or horizontal. They wore a collar restricting their visual field so that they could not even see their body. This stopped at the age of 5 months.

Question 5

Findings

Answer 5

1. Visual experiences in the early life of kittens can modify their brains and have profound perceptual consequences because our neutrons adapt to the environment, e.g. some defects such as moving with clumsy, jerky head movements and trying to touch things beyond their reach were permanent.
2. Brain development is determined by the functional demands made upon it, rather than pre-programmed genetic factors, e.g. the kittens showed ‘behavioural blindness’ in that the kittens raised in the horizontal environment could not detect vertically aligned objects and vice versa.