Sperry Flashcards
Background on Sperry, 1968 study on split brain 
Hemisphere of the brain
The brain has two hemispheres left and right joined by the corpus callosum
Hemisphere disconnection ( split brain ) involves cutting the connections between the left hemisphere and right hemisphere
Aim on Sperry, 1968 study on split brain
To investigate the psychological effects of hemisphere connection in patients with severe epilepsy
How the left hemisphere, right hemisphere working in individuals with an intact brain
Method design
Controlled, observation and snapshot study series of clinical case studies. This is also a quasi experiment, independent groups design
IV- PRESENTS OR ABSENCE OF SPLIT BRAIN
DV- participants performance on various visual and tactile tasks
Sample on Sperry, 1968 study on split brain
Opportunity, sample of 11 patients who had split brain operation following severe epileptic seizures. Patients were referred to the white memorial centre in Los Angeles USA
Material/ apparatus on Sperry, 1968 study on split brain
A tachistoscope -a device that displays visual stimuli that are back projected onto a screen
objects for tactile tasks. E.g. keys
Procedure
Participants were seated in front of the screen and asked to focus on a cross in the middle of the screen when eye was covered
Images with floss on the screen each four0.1 second so that the eye could only have time to process the image in the visual field where it was placed
The tasks test how the left hemisphere and right hemisphere respond to input from left visual field and right visual field and left and right hand
Tasks used to test abilities
Visual and verbal task. Participants were shown one image to the LVF and a different image to the RVF asked to say alright what they saw.
Visual materials shown to one visual field only visual tactile task. Participants were asked to select an object from below the screen to match what they saw
Dual processing, tactile tasks, two objects were placed simultaneously, one in each hand, and then hidden in a pallet objects, each hand was required to recognise the objects
Every day life participants interviewed about every day affects
Results?
Visual and verbal task display $ to LVF and ? Sign and control $with left hand.
One visual field only =
RVF, only participant, described visual material and speech and writing as normal
Visual and tactile task when an object was placed in the left-hand participants made wild guesses and were unaware they were holding anything
Every day life participants were able to watch TV or read books with no complaints, and their intellect and personality were unchanged, but they reported short-memory deficits and difficulties with concentration
Conclusions
Functions are lateralised in the brain
The right hemisphere silent, as it cannot respond, verbally it can respond with some emotion, e.g. giggling
In a sense, we all have two minds in one body
Research method and techniques
+ the use of objective test to measure the patient’s capabilities provides an unbiased means of assessing the effect of the operation, so high internal validity, for example, showing $and? Sign two different visual fields to see which could be described verbally.
-The study is a quasi experiment, so certain confounding variables can’t be controlled. E.g. differences, impatient behaviour test compared to participants with an intact brain could be due to the epilepsy rather than the split brain.
Reliability
Participants were tested on the variety of tasks, carried out the same way each time
Sampling bias
Using participants with a split brain provide an opportunity to study one aspect of the brain function that would not be possible in an intact brain
A sample size of 11 was relatively small, individual differences, e.g. handedness may have affected the results
Types of data
Primary qualitative data, e.g. patient responded to assemble display to RVF data specifically focused on aims of study and gave Rich in-depth detail about the effect of the split brain operation
Ethical considerations
Participants with a split brain may have found it difficult to give form consent due to trauma of surgery or epilepsy
Ethnocentrism
The split brain operation describes in the study were conducted in America, possibly reflect an American and European concerned with the measurement of behaviour, and the identification of localised components of the brain as a means of understanding behaviour
