sperry (1968)- split brain

Question 1

research method

Answer 1

quasi/natural exp bcos IV (split brain or not) was not directly manipulated by researchers. Participants with split-brains had already undergone hemisphere deconnection to reduce severe epilepsy
DV: the p’s ability to perform a variety of visual and tactile tests
such extensive tests were carried out on a very small sample (11 split brainers in total)

Question 2

sample

Answer 2

11 p’s undergone split brain. first p was a man who has his surgery over 5 1/2 years before study
second p = housewife who had it in her 30s, 4 years before study
the other 9 p’s had their surgery at varying times but not long before the study was conducted.

Question 3

outline procedure

Answer 3

Key tests
• Presenting visual information
The participant, with one eye covered, centred his gaze on a fixed point in the centre of an upright translucent screen. Visual stimuli on
35-millimetre transparencies were arranged in a standard projector and were then back-projected at 1/
10 of a second or less – too fast for eye
movements to get the information into the wrong visual field. Everything projected to the left of the central meridian of the screen is passed via
the left visual field (LVF) to the right hemisphere and vice versa (regardless of which eye is used).
• Presenting tactile information
Below the translucent screen there was a gap so that participants could reach objects but not see their hands. Objects were then placed in
either the participant’s right / left hand or both hands. Information about objects placed in the left hand is processed by the right hemisphere
and vice versa.
• Participants undertook a variety of both visual and tactile tests.
This apparatus is called a tachistoscope.
• Sperry also conducted a variety of other tests which highlighted the lateralisation of brain function. These can be found in the original study

Question 4

conclusions

Answer 4

people with split brains have two separate visual inner worlds, each with its own train of visual images.
• Split-brain patients have a lack of cross-integration where the second hemisphere does not know what the first hemisphere has been doing.
• Split-brain patients seem to have two independent streams of consciousness, each with its own memories, perceptions and impulses ie two
minds in one body