Biological area Flashcards
(42 cards)
Sperry aim
Investigate the effects of disconnection between the hemispheres of the brain after the cut corpus callosum
Sperry research method
Quasi experiment
Sperry participants
11 participants that underwent split brain surgery for treatment for epilepsy
Sperry procedure
Expose a hemisphere to a stimuli either tactile or visual
Sperry procedure pt1
A picture of an object was projected to the RVF or LVF for a 1/10th of a second. They are asked to recognise it verbally
Visual stimulus projected to either VF and asked to describe it then write it down.
Sperry procedure pt2
Visual stimuli was presented simultaneously to both hemispheres. Were asked to draw with the left hand and say what they had drawn
Then words composed of 2 smaller words were shown. One to each VF. and say it
Sperry results
Quant and qual data gathered
Pictures only recognised if flashed to the same visual field again
Participants could only describe objects shown to RVF as left hemisphere controls speech
Participants could only write down objects shown to RVF Report only seeing a flash of light.
Could point to an object when shown to LVF. Because hands are controlled collaterally.
Participant can draw what is shown to LVF with left hand but instead describe what is shown to the RVF.
Sperry conclusions
In split brain patients the information shown to one hemisphere cant be shown to the other hemisphere.
Memory is independent in either hemisphere
Sperry validity
The procedure was highly controlled so it eliminated extraneous variables. EG. had to keep hands on tables shown for 1/10th of second.
Lacks ecological video. Uses lab environment. Cant be generalised because not done on typical brain. The sample is too small
Sperry reliability
Standerdized procedure. Lab procidure so it is easy. Shown for 1/10th seccond. Keep hands on the table
Sperry sampling bias
Sample made of 11 men and women who went through surgery
Very small sample and since not done on typical brain the findings are not representative or generalise.
Sperry ethnocentrism
Some cultures might be less lateralized in their speech functions Only done on english speakers
Casey aim
To test whether delay of gratification as a child has an effect on impulse control as an adult
Casey participants
started with 562 participants and ended with 59
Casey research method
Quasi experiment that used a longitudinal design
Casey procedure
At 4 years old participants were told not to eat the cookies.If they did low delayer if didn’t then high delayer
In 20’s 155 took a questionnaire on self control
In 30’s 135 retook same questionnaire
From this high delayers and low delayers away from the average were contacted and 59 took part in experiment in their 40’s
Casey procedure 2
32 high delayers and 27 low delayers. Did a hot and cool impulse task.
Press button or not. Go no go task
Showed faces with neutral expressions which is not appealing female and male faces determine go or not
Then 15 high delayers and 11 low delayers. Use an fMRI scan and facial expression is go no go task.
Hot task low delayers made more errors
Casey conclusions
Low delayers stay low delayers can learn cooling techniques
Resistance to temptation stays stable
High delayers were more stimulated in inferior frontal gyrus
Low delayers more stimulated in ventral straitum
Casey data
Quantitative data eg stimulation score on the questionnaire. Whether ate the cookie or not
But no info why their brains varied
Casey validity
Lacks ecological validity. Uses fMRI scanning so possibly demand characteristics. Also go no go task is not real
Casey reliability
Uses fMRI scanning and controlled
Casey sampling bias
All 562 went to the same nursery but the future experiments had very small sample sizes. All from same area and time period
Casey ethnocentrism
Impulse control might be different in other societies but this looks at brain function which is separate to culture
Sperry + Casey similarity
Both lack ecological validity
