Sperry (1968) Hemisphere Deconnection and Unity in conscious awareness

Question 1

What is the aim?

Answer 1

The aim of Roger Sperry’s study was to investigate the effects of hemisphere disconnection and to show that each hemisphere has different functions

Question 2

What is the procedure?

Answer 2

• Studied a group of 11 who had all undergone disconnection of the cerebral hemisphere as they all had a history of advanced epilepsy which could not be controlled by medication
• Sperry got the participants to carry out a number of visual and tactile tasks using specialised equipment and the tasks separately to the two hemispheres
• In the visual task, a picture was presented to either the left or right visual field and the participant was asked to simply describe what they saw
• An image was projected very quickly ( 1/10 of a second) to the patients left visual field ( which is processed by the left visual field)
• For the tactile test, an object ( which was out of sight) was placed in the patients left or right hand and they had to either describe what they felt

Question 3

What are the findings?

Answer 3

Visual test
. When an object is displayed in the right visual field
. ( which is processed in the left hemisphere),
. participants can describe it well in speech and.
. writing.
But when an object is displayed in the left visual field
(which is processed in the right hemisphere)
participants struggled to say what they had seen

Tactical Test
. For objects placed in the right hand (which is.
. processed in the left hemisphere)
. participants described the object clearly in both
writing and speech.
.But when an object is placed in the left hand (which is
.processed in the right hemisphere
. participants could not say what was in their hands
and had to make guesses.

. when an object is displayed in the left visual field
. (which is processed in the right hemisphere)
. Participants could draw the object out

Question 4

What is the Conclusion?

Answer 4

Sperry’s research shows a number of key differences
between the 2 hemispheres & that it can work
independently from each other.
. For split-brain patients, he proves that the 2nd
hemisphere does not know what the 1st hemisphere
has been doing.
. Different Areas of the BRAIN specializes in different
tasks, FOR EXAMPLE, THE LEFT HEMISPHERE IS
MORE IN CONTROL OF SPEECH AND LANGUAGE &
THE RIGHT HEMISPHERE IS MORE IN CONTROL OF
VISUAL MOTOR TASKS

Question 5

What are the Strengths

Answer 5

Sperry’s procedure was carried out in a proper lab and used specialized equipment and highly standardized procedures - this means the information collected in the form of numbers and frequencies were analyzed statistically.
THE INFORMATION GATHERED IS RELIABLE.

Question 6

What are the Weaknesses

Answer 6

• The information gathered was from patients being -
• tested in a lab. This meant the findings were from a
• fake environment and not from a real-life -
  environment
  AND
• The 11 split-brain patients Sperry used were all -
• lumped together. IT IS DIFFICULT TO TELL HOW
• LONG EACH PATIENT HAD UNDERGONE DRUG
• THERAPY. THIS COULD HAVE AFFECTED THE -
• FINDINGS.