Sperry (1968) Hemisphere Deconnection and Unity in
Conscious Awareness
Aims: Results: Strengths:
To find out the cognitive functions that are linked to each hemisphere in the brain Task 1: Sperry projected the words ‘KEY’ (left) and ‘CASE’ (right) and asked participants to He gathered a lot of detailed
The experiments aimed to assess the behavioral, neurological and psychological identify the object they saw on each side: information, improving the reliability of
his study
effects of the split-brain surgery on the patients ● The patients could say ‘case’ and write it as normal
He designed procedures (such as the
● They reported not seeing anything to the left side split-screen for presenting visual
● However if asked to select the item they saw to the left with their left hand, information) that could be kept the
they could choose the key correctly from either the items behind the screen or same for each participant, meaning
Procedure: data was gathered in a reliable way
from an array of images
Sperry reports on 11 patients who had undergone surgery for severe epilepsy and each participant’s results can be
● This indicated that the left visual field was being processed by the right
Sperry used a piece of apparatus that allowed testing of the right and left halves of compared more easily
hemisphere and the left hand by the right hemisphere
the visual field separately or together
Task 2: If patients used their right hand they could name the object with ease if they used
Task 1: Patients had to fix their eye gaze on a particular spot then projected words or
their left hand they were unable to name it, but able to retrieve it only with their left hand
Weaknesses:
pictures for 1/10th of a second (too fast for eye movements which ensured that info The sample of 11 participants is too
from a grab bag
only entered 1 hemisphere), then had to feel for a particular object (hidden amongst small to be able to be generalised, and
Task 3: Patients were able to pick a wristwatch with their left hand and connected a ‘piece very few people have surgery to sever
others) behind a screen to identify what they had apparently seen with their eyes
of silverware’ with a fork, showing limited language processing ability in the right the corpus callosum so results might
Task 2: Sperry asked patients to pick an item from a bag and name the object
hemisphere not be that useful for explaining how
(without seeing it) ‘normal’ brains work
Task 4: Patients’ left hands could point to the correct answer, demonstrating that the right
Task 3: Sperry showed a picture of a wall clock to the patient’s right hemisphere and The experiment took place in a
hemisphere was involved in basic calculations
asked them to pick the object closest to what they had seen with their left hand laboratory, meaning the settings are
Task 5: The picture of a nude would produce blushing or giggling, with no report verbally of
Task 4: A sum was shown to the right hemisphere and patients were asked to use very artificial therefore lacking
having seen the image (demonstrates that the right hemisphere was involved in emotional
their left hand to point to what they thought was the correct answer to the sum ecological validity as procedure was
processing) not a typical task
Task 5: A picture of a nude was presented to the right hemisphere to see what the
Task 6: The right hemisphere was judged to be superior to the left hemisphere in tasks
reaction would be
involving drawing spatial relationships and performing block design tasks
Task 6: Patients performed block design tests - a type of spatial task (described as
‘work in progress’)
Conclusions:
The left hemisphere was the primary hemisphere for the processing of language
Sperry showed limited language processing in the right too
The right hemisphere was able to read words (enabling the patients to recognise
objects), make mental associations, process emotional reactions and solve
simple arithmetic
The right was also better than the left hemisphere at spatial tasks
Conscious Awareness
Aims: Results: Strengths:
To find out the cognitive functions that are linked to each hemisphere in the brain Task 1: Sperry projected the words ‘KEY’ (left) and ‘CASE’ (right) and asked participants to He gathered a lot of detailed
The experiments aimed to assess the behavioral, neurological and psychological identify the object they saw on each side: information, improving the reliability of
his study
effects of the split-brain surgery on the patients ● The patients could say ‘case’ and write it as normal
He designed procedures (such as the
● They reported not seeing anything to the left side split-screen for presenting visual
● However if asked to select the item they saw to the left with their left hand, information) that could be kept the
they could choose the key correctly from either the items behind the screen or same for each participant, meaning
Procedure: data was gathered in a reliable way
from an array of images
Sperry reports on 11 patients who had undergone surgery for severe epilepsy and each participant’s results can be
● This indicated that the left visual field was being processed by the right
Sperry used a piece of apparatus that allowed testing of the right and left halves of compared more easily
hemisphere and the left hand by the right hemisphere
the visual field separately or together
Task 2: If patients used their right hand they could name the object with ease if they used
Task 1: Patients had to fix their eye gaze on a particular spot then projected words or
their left hand they were unable to name it, but able to retrieve it only with their left hand
Weaknesses:
pictures for 1/10th of a second (too fast for eye movements which ensured that info The sample of 11 participants is too
from a grab bag
only entered 1 hemisphere), then had to feel for a particular object (hidden amongst small to be able to be generalised, and
Task 3: Patients were able to pick a wristwatch with their left hand and connected a ‘piece very few people have surgery to sever
others) behind a screen to identify what they had apparently seen with their eyes
of silverware’ with a fork, showing limited language processing ability in the right the corpus callosum so results might
Task 2: Sperry asked patients to pick an item from a bag and name the object
hemisphere not be that useful for explaining how
(without seeing it) ‘normal’ brains work
Task 4: Patients’ left hands could point to the correct answer, demonstrating that the right
Task 3: Sperry showed a picture of a wall clock to the patient’s right hemisphere and The experiment took place in a
hemisphere was involved in basic calculations
asked them to pick the object closest to what they had seen with their left hand laboratory, meaning the settings are
Task 5: The picture of a nude would produce blushing or giggling, with no report verbally of
Task 4: A sum was shown to the right hemisphere and patients were asked to use very artificial therefore lacking
having seen the image (demonstrates that the right hemisphere was involved in emotional
their left hand to point to what they thought was the correct answer to the sum ecological validity as procedure was
processing) not a typical task
Task 5: A picture of a nude was presented to the right hemisphere to see what the
Task 6: The right hemisphere was judged to be superior to the left hemisphere in tasks
reaction would be
involving drawing spatial relationships and performing block design tasks
Task 6: Patients performed block design tests - a type of spatial task (described as
‘work in progress’)
Conclusions:
The left hemisphere was the primary hemisphere for the processing of language
Sperry showed limited language processing in the right too
The right hemisphere was able to read words (enabling the patients to recognise
objects), make mental associations, process emotional reactions and solve
simple arithmetic
The right was also better than the left hemisphere at spatial tasks
