Sperry et al (1968)

Question 1

What are the main functions of the left and right hemisphere of the brain?

Answer 1

The lefts role is language, reasoning and logical thought.

The right hemispheres function is creativity, imagination and spacial awareness.

Question 2

What hemispheres of the brain control each hand?

Answer 2

The right hemisphere controls of the left hand, while the right hemisphere controls the right hand.

Question 3

What was the aim of Sperry’s research?

Answer 3

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

Question 4

What was the research method used in research by Sperry?

Answer 4

A quasi experiment.
Can also be augured that that because extensive tests were carried out on so few participants it could be seen as a set of case studies.

Question 5

What was the IV in research by Sperry?

Answer 5

IV: having a split brain or not Participants with split-brains had already undergone hemisphere deconnection to reduce severe epilepsy. No
actual control group was necessary for comparison in the study because the functions and abilities of the visual fields and hemispheres in non
split-brain individuals was already known.

Question 6

What was the DV in research by Sperry?

Answer 6

DV: the participant’s ability to perform a variety of visual and tactile tests

Question 7

What was the sample Sperry used?

Answer 7

• 11 patients who had undergone an operation to sever their Corpus Colosseum for treatment of epilepsy.
There operations took place at a range of times from the earliest being 5 and a half years ago.

Question 8

What were the key tests conducted?

Answer 8

Visual test

Tactile test

Question 9

What was the visual test used?

Answer 9

The participant (with one covered eye) centred their gaze on a screen.

A visual stimulus appeared on the screen from 1/10 of a second, to fast to get the eyes in the wrong visual field.

Everything projected to the left of the screen is passed via
the left visual field (LVF) to the right hemisphere and vice versa.

Question 10

What was the tactile test used?

Answer 10

Below a screen there was a gape so participants could reach object but not see them.

Objects were placed in either the Ps left or right hand or both hands.

Information about the objects placed in the left hand is processed by the right hemisphere and vica versa.

Question 11

What were the key findings from the visual test?

Answer 11

Information shown and responded to in one visual field could only be recognised again if shown to the same visual field.

Information present to the RVF could be described in speech. If the same information was present to the LVF the participant said they did not see anything. However the participant could point with his left hand to a matching picture of the object.

$ sign to the LVF and ? to the RVF, the participant could draw the $
sign with his left hand but reported that he had seen a ?

Question 12

What were the results for the tactile tests?

Answer 12

Objects placed in the right hand could be described in speech or writing.

If the same objects were placed in the left
hand participants could only make wild guesses and often seemed unaware they were holding anything.

When two objects were placed simultaneously in each hand and then hidden in a pile of objects, both hands selected their own object and
ignored the other hand’s object.

Question 13

What are the main conclusions from Sperry’s research?

Answer 13

People with split brains have two separate visual processors, each with its own train of visual images.

Split-brain patients have a lack of cross-integration.

Split-brain patients seem to have two independent streams of consciousness, each with its own memories, perceptions and impulses ie two
minds in one body.

Question 14

Evaluate the research method used by Sperry

Answer 14

Highly controlled experimental design, such as the time the image showed up for.

As it was a Quasi experiment it may have been hard to change the effects of previous treatment such as drug treatment participants had had.

Question 15

Evaluate the data collected by Sperry

Answer 15

The data collected was qualitative descriptions of participants actions, this provided rich and detailed data.

However if quantitative data was collected it would of been easier to quantify and directly compare between groups. The qualitative data interpretations may have been subjective.

Question 16

What are the possible ethical considerations in this research?

Answer 16

The experiment kept to all ethical guidelines.

Question 17

Assess to what extent Sperry’s research can be seen as valid.

Answer 17

The sample was very small, this puts into question whether the abnormal behaviour shown is generalisable to a normal brain.

The differences in their brain may be caused by epilepsy or the medication they take..

Question 18

Assess to what extent Sperry’s research can be seen as ecologically valid.

Answer 18

The findings are unlikely to be reproduced in real life, because a person with a severed Corpus Collusum would compensate by using both sides of their hemispheres.

However brain structure is physiological and should not vary depending on your social setting meaning the findings of the roles of your hemisphere would be generalisable.

Question 19

Assess to what extent Sperry’s research can be seen as ecologically reliable.

Answer 19

Sperry found a general tends in lateralisation of brain function in the split brain participants.

Question 20

Evaulate the sample used in Sperry’s research.

Answer 20

The sample was small and you have to question whether abnormal behaviour can be generalised to a normal brain.

Question 21

Discuss the extent to which research by Sperry can be seen as ethnocentric

Answer 21

One the one hand brain lateralisation is affected by the anatomy and physiognomy of our brain, you can argue that this is not ethnocentric as it is species specific behaviour.

However our environment and culture affect brain development.

Question 22

To what extent does research by Sperry support psychology as a science?

Answer 22

Sperry conducted controlled lab experiment which fulfilled scientific criteria of control, evidence and replication.

It is falsifiable.

Question 23

To what extent does research by Sperry be considered useful?

Answer 23

Sperry’s work allowed a greater understanding of the physiognomy of the brain.

It revealed the importance of the Corpus Callosum.

Question 24

Discuss relation by Sperry in relation to the free will vs determinism debate

Answer 24

Sperry’s study suggests a position of biological determinism, the functions of the brain are fixed.

Question 25

How does reserach by Sperry link to the biological area?

Answer 25

It investigates regions of the brain and lateralisation of brain function.

Question 26

How does reserach by Sperry link to the key theme?

Answer 26

Regions of the brain.
Discovered the importance of the Corpus Callasum as a communication pathways between two hemispheres.

Outline the functions of the left and right hemispheres.