regions of the brain: sperry

Question 1

sperry method?

Answer 1

quasi expt

could be considered collection of case studies due to small sample

Question 2

sperry equipment?

Answer 2

tachistoscope

Question 3

sperry sample?

Answer 3

11 commissurotomy patients from an la hospital

one had surgery 5.5 years ago, another 4 years before and others were more recent

Question 4

sperry visual tasks?

Answer 4

images shown to one or both visual fields simultaneously

ps had one eye covered and were asked to look at a fixation point at the centre of the screen

image was projected for 1/10th of a second

Question 5

sperry why 1/10th of a second?

Answer 5

ensures eye only has time to process the image in the intended field

as not enough time for eye or head to move and send image to other field

Question 6

sperry one visual field test?

Answer 6

test 1:

an image was shown to one visual field

image presented again to either the same or different visual field

then asked if they recognised the image

Question 7

sperry both visual fields test?

Answer 7

test five:

different images projected to each visual field

p had to draw what they’d seen with their left hand (while hidden)

and then say what they’d seen

Question 8

sperry tactile test?

Answer 8

test 8:

symmetrical hand pose test

hands hidden and one was posed into a certain position

then asked to imitate this with the other hand

Question 9

sperry right hemisphere test?

Answer 9

sequence of shapes projected to both fields

within this was a nude image projected to the left visual field

Question 10

sperry one visual field results?

Answer 10

test 1:

image only recognised as repeated when presented to the same visual field

each hemisphere has its own memory

Question 11

sperry both visual fields results?

Answer 11

test 5:

ps draw what was presented to the lvf (right hemisphere) and say what was presented to the rvf (left hemisphere)

Question 12

sperry tactile results?

Answer 12

test 8:

ps could not imitate the pose with other hand

Question 13

sperry right hemisphere results?

Answer 13

ps would giggle when nude image appeared

but couldn’t explain why

shows right hemisphere has consciousness with appropriate emotional reactions

Question 14

sperry conclusions?

Answer 14

supports idea that the brain has two independant hemispheres that need an intact corpus callosum to transfer information

left hemisphere is dominant as it has the speech centres which are unavailable for information only presented to lvf for split brain patients

each hemisphere is unaware of what the other is doing, and has its own perceptions, memories and abilities

ps behaviour seems to come from two people rather than one

Question 15

sperry method evaluation?

Answer 15

high control with some direct conditional comparisons

results compared to non-split brain adults not part of this study

however history of drug therapy and epilepsy may mean their brains are different without a commissurotomy

Question 16

sperry data collected evaluation?

Answer 16

quantitative and qualitative data

number of ps who couldn’t complete the tasks and comments/behaviours such as commenting on their hand being numb or laughing

Question 17

sperry ethicality evaluation?

Answer 17

no deceit, deception or harm

ps had right to withdraw and informed consent

Question 18

sperry validity evaluation?

Answer 18

tachistoscope and timed exposure ensured control of the information being presented

results therefore valid reflections of the functionality of the individual hemispheres

low ecological validity due to the artificial tasks and that split brain patients would rarely be in such a situation

but study was looking into the biological function of the hemispheres and didn’t need to represent a real situation

Question 19

sperry sampling bias evaluation?

Answer 19

small sample but commissurotomy rare

gender balance unknown but presence of at least one female

use of epilepsy patients is a problem for generalisability

operation have mild side effects on short term memory and attention span

Question 20

sperry link to theme?

Answer 20

links to regions of the brain as sheds light on the function of the corpus callosum as well as the capabilities of the two hemispheres

Question 21

sperry link to area?

Answer 21

falls within biological area as it is investigating regions of the brain and the lateralization of brain function

demonstrates the importance of the corpus callosum in transferring information between the two hemispheres