Sperry Flashcards
Key theme
Regions of brain
What is epilepsy
Abnormal electrical impulses discharge within brain disrupting normal brain patterns
Background
1940s treatment (Commissurotomy) Split Brain Surgery - corpus callossum cut so impulses couldn’t spread to all of brain
Researched patients to see what each hemisphere does
Define lateralisation of function
One side of brain has different role from other
Define corpus callosum
fibres that carry majority of info between the 2 hemispheres
Define contralateral control
each side of body is controlled by other side of brain
commissurotomy
surgical op to sever corpus callosum
Aim
To study functions of separated and independent hemispheres
Sample
11 epileptic patients who had gone through commissurotomy from a surgery in America
A group of non epileptics to compare to
Advantage of sample
Able to test hemispheres independently as they were separated
Weaknesses of sample
Small
2 had surgery 4+ years ago so may have recovered
Maybe cause of results was epilepsy
What was the main piece of equipment used called
Tachistoscope
Name 4 other pieces of equipment
Fixation point
Hand shield
Projector
Objects
Name some controls
Symbols all same
Images all same
Objects all same
Fixation point same
1/10 sec per image
Hands out of view
One eye covered
What happened when objects were flashed to the right visual field?
Info went to left hemisphere and they said what they saw
What happened when objects were flashed to the left visual field?
Info went to the right hemisphere and they drew or pointed to the object with their left hand
Couldn’t say what they saw
What happened when different things were shown in the 2 visual fields (apple in LVF and key in RVF)
The apple went to the right hemisphere and they could draw this with their left hand
The key went to the left hemisphere and they could say they saw the key
They couldn’t explain why they drew an apple
What happened when simple maths problems were shown to the LVF
Info went to the right hemisphere and they could write an answer with their left hand
What happened when a pic of a nude pinup was shown to the LVF
Info went to the right hemisphere and they laughed/were embarrassed but couldn’t say why
What happened when objects were felt with the right hand
Info went to left hemisphere and they could say what they were holding
What happened when objects were felt by the left hand
Info went to the right hemisphere and they could point to/find the object with their left hand.
They couldn’t say what they were holding
Conclusions about L hemisphere
has language ability and controls the right side of body
Conclusions about R hemisphere
Can only communicate non verbally and controls left side of body
What ethics were upheld
Confidentiality
Informed consent
Deception - fully aware of research
What ethics were broken
Protection from harm - confusion may have upset participants
Was the study ethnocentric
All from America
Roles of each hemisphere should be universal so maybe doesn’t matter
Internal reliability
Was highly controlled
External reliability
Only 11 epileptic participants
Not large enough to show consistent effect
All same biologically so doesn’t matter
Internal validity
Results could be due to epilepsy not the surgery
External validity (population)
Specific sample so not generalisable
Biology all same so maybe doesn’t matter
External validity (ecological)
Visual tasks - not realistic to see things for 1/10 second with one eye
Tactile - relatively normal
How does this study link to usefulness
can identify capabilities for those with brain damage
How does this study link to Psychology as a science
Is falsifiable and replicable
Data is objective
How does this study link to nature/nurture
Nature as looks at natural brain abilities not influenced by experiences
How does this study link to reduction/holism
Reductionist as only takes into consideration biological explanations of behaviour
