Sperry (1968)

Question 1

(Sperry) Describe the background for this study.

Answer 1

Epilepsy is a condition is brought on by abnormal electrical impulses discharging within the
brain disrupting normal brain patterns.
In the 1940’s a treatment was developed called ‘Split Braielectrical impulses could not spread throughout the brain.
Sperry thought that patients who had undergone split brain surgery were perfect participants for research into what each hemisphere of the brain actually does.

Question 2

(Sperry) Define the term ‘Lateralization of Function’.

Answer 2

One side of the brain has a different role from the other.

Question 3

(Sperry) Define the term ‘Corpus Callosum’.

Answer 3

Fibres that carry the majority of information between the two hemispheres of the brain.

Question 4

(Sperry) Define the term ‘Contralateral Control’.

Answer 4

The idea that each side of your body is controlled by the other side of your brain.

Question 5

(Sperry) Define the term ‘Commissurotomy’.

Answer 5

Surgical operation to sever the corpus callosum.

Question 6

(Sperry) What is the aim of the study?

Answer 6

To study the functions of separated and independent hemispheres.

Question 7

(Sperry) Describe the sample that was used in this study.

Answer 7

Epileptic
- 11 patients who had undergone a
commissurotomy as a treatment for their
epilepsy. They were obtained from a surgery within America.

Nonepileptic
- They were compared with a group of people
who had not undergone the surgery.

Question 8

(Sperry) What was a strength of the sample?

Answer 8

Able to test the hemispheres independently as they were separated in the surgery.

Question 9

(Sperry) What were weaknesses of the sample?

Answer 9

• Small sample size
• 2 people had the surgery 4-5 years prior so may have recovered
• Perhaps the cause of results was epilepsy

Question 10

(Sperry) List the controls used in this study. (8)

Answer 10

• Symbols displayed
• Images displayed
• Objects used
• Fixation point
• 1/10th second time for presentation
• Hands out of view
• One eye covered
• Tachistoscope

Question 11

(Sperry) Describe the abilities of the left hemisphere.

Answer 11

Has language ability (both written and verbal) and controls the right hand side of your body.

Question 12

(Sperry) Describe the abilities of the right hemisphere.

Answer 12

Can only communicate
non-verbally and controls the left hand side of your body.

Question 13

(Sperry) How does the ethical consideration of informed consent relate to this study?

Answer 13

Participants consented to participate following being approached through their hospital.

Question 14

(Sperry) How does the ethical consideration of confidentiality relate to this study?

Answer 14

Details of each participant were kept confidential.

Question 15

(Sperry) How does the ethical consideration of deception relate to this study?

Answer 15

Participants were fully aware on the research.

Question 16

(Sperry) How does the ethical consideration of protection from harm relate to this study?

Answer 16

May have been upsetting or embarrassing to not have full capabilities or understanding of your behaviour.

Question 17

(Sperry) How does the concept of ethnocentrism relate to this study?

Answer 17

The sample were obtained from a hospital in America but the roles of each brain hemisphere should be universal so perhaps it doesn’t matter.

Question 18

(Sperry) How does internal reliability influence this study?

Answer 18

The procedure was very standardised and easy to replicate due to the amount of controls (e.g. images shown for 1/10th of a second).

Question 19

(Sperry) How does external reliability influence this study?

Answer 19

The sample was only 11 split brain patients and therefore perhaps not large enough to establish a consistent effect. Although perhaps biologically as we are all the same does this matter?

Question 20

(Sperry) How does internal validity influence this study?

Answer 20

Perhaps the behaviour can be explained as a result of their epilepsy not the surgery.

Question 21

(Sperry) How does external (population) validity influence this study?

Answer 21

The sample was very specific (epileptic people who have has split brain surgery) so perhaps
not generalizable but does it matter based on our natural biology?

Question 22

(Sperry) How does external (ecological) validity influence this study?

Answer 22

Visual - the tachistoscope procedure not very realistic as we see things for more than
1/10th of a second so our brain could adapt.
Tactile - feeling around and not being able to see your hands is relatively normal.

Question 23

(Sperry) How does the ethical consideration ‘Psychology as a Science’ relate to this study?

Answer 23

Falsifiable and replicable as can be repeated again in lab conditions and proven false. The data is very objective based on the participants’ abilities.

Question 24

(Sperry) How does the ethical consideration ‘Nature/Nurture’ relate to this study?

Answer 24

Nature as investigates natural brain abilities rather than influenced by experiences.

Question 25

(Sperry) How does the ethical consideration ‘Reductionism/Holism’ relate to this study?

Answer 25

Reductionist as only takes into consideration biological explanations of behaviour.

Question 26

(Sperry) How does the ethical consideration ‘Usefulness’ relate to this study?

Answer 26

Perhaps useful in identifying capabilities for those with brain damage.