Psychology 9-1 GCSE - 

4.2.2 - Sperry (1968) Hemisphere Deconnection and Unity in Conscious Awareness:

Aims - 

To show the independent streams of conscious awareness possessed by each hemisphere and to show how each hemisphere has its own memories. 

Procedures - 

It had two visual fields. Left is what we can see on our right, right is what we can see on our right. Information from the left visual field goes to the right hemisphere. Information from the right visual field goes to the left hemisphere. They were given visual tasks and stimuli and tactile tasks. 

Results - 

Participants would recognize the stimuli if it was presented again to the same visual field, but if it was presented to a different one from before, they would claim to never have seen it. Objects placed in the right hand could be described in speech or writing, if the same objects were placed in the left hand participants couldn't recognize them. 

Conclusions - 

People with split brains have two separate visual inner worlds, each with its own train of visual images. Split-brain participants 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.

Strengths - 

• Ethics; as the study used a quazi methodology, sperry did not need to manipulate anything. 

Weaknesses - 

• As it was a quazi study (no manipulation) establishing a cause and effect can be difficult.
• No control group.
• It has low external validity as the stimuli was selectively delivered to one hemisphere.