Sperry

Question 1

The aim

Answer 1

To study the function of separated and independent hemispheres, specifically to see the effect of hemispheric deconnection in split-brain patients.

Question 2

Why participants had previously undergone an operation to deconnect the two hemispheres of the brain

Answer 2

Participants suffered from epilepsy which couldn’t be controlled by medication.

Question 3

One problem with generalising the sample

Answer 3

To reduce the effects of epilepsy, the sample was too small (11) so one may not be able to generalise the findings to the wider population.

Question 4

What is meant by ‘hemisphere deconnection’

Answer 4

Involves cutting trough the cerebral commisures which connect the left and right hemispheres of the brain.

Question 5

One control

Answer 5

All materials (visual and tactile) were presented to all participants using the same testing set.

Question 6

How visual stimuli was presented

Answer 6

The participant, with one eye covered, centred their gaze on a designated fixation point. The visual stimuli were arranged on a standard projector which were then back-projected for 1/10 of a second to either the right or left of the central fixation point.

Question 7

Why patients couldn’t identify in words material presented to their LVF

Answer 7

Because material presented to the LVF is received by the right hemisphere which you cannot speak or write.

Question 8

Two ways having a split brain affected performance

Answer 8

When shown an image to the right visual field:

1) Patients could describe it in speech and writing
2) Patients could point to it with their right hand

Question 9

Two findings

Answer 9

1) Visual material presented to the RVF can be described in speech and writing.
2) Objects placed in one hand can only be identified through touch alone by the same hand.

Question 10

One difference between ‘split-brain’ patients and ‘normal’ people in their ability to identify objects by touch alone.

Answer 10

If two objects were placed one in each hand of split brain participants, each hand could only search for and find its own object from a collection of objects whereas a ‘normal’ person could use either.

Question 11

Outline one reason for this difference

Answer 11

Objects placed in right hands are identified by left hemisphere which controls speech.

Question 12

Outline one conclusion

Answer 12

1) The right hemisphere controls emotional responses.

2) The individual has separate streams of consciousness.

Question 13

Why in everyday life, these patients do not experience the problems identified in this study

Answer 13

Because normally an individual doesn’t have only 1/10 of a second to identify material flashed to one visual field only.