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Biological area sperry and casey - Coggle Diagram
Biological area sperry and casey
Sperry 1968
Background - 600,000 people in uk with epilepsy. Can cause uncontrollable seizures. Treatment = commissurotomy where corpus callosum is cut
Sperry investigated on cats+monkeys. Found could teach one hemisphere while other unaware. Each hemisphere controls opposite side of body
Aim - investigate functions/abilities of each hemisphere + effect of deconnection
Sample - 11 patients who had undergone commissurotomy
Controls - told to stay quiet, images flashed for 1/10th second covered one eye
Procedure - visual task - showing 1 stimulus at a time to 1 visual field or showing 2 simultaneously to left and right visual fields
Tactile task - Tactile info presented to either left/right hand or both without seeing what object is. Hands hidden behind screen.
Conclusion - left hemisphere has language ability + controls right visual field/side of body
right hemisphere has no language ability but communicates presented info non verbally and has separate consciousness. Can do simple math and process emotions
Evalation
Validity
Internal - several controls in place so no extraneous variables. However different between participants brain and people without epilepsy
External - diverse sample but not representive because of commissurotomy(population). visual task low ecological validity. Tactile task more realistic as we may feel for objects out of sight.
Reliability
Internal - fairly standardised. Info presented in same way
External - brain is universal so less results needed for reliable effect.
Ethnocentrism - individual differences. Environment/culture affects how brain develops so not generalisable to everyone
debates
Determinism - behaviour determined by our biology. Show by participants unable to name objects presented to right hemisphere. Determined by brain anatomy so no choice over it.
Psych as science - replicable - controlled lab experiment. Falsifiable - possible to prove wrong saying about abilities of people undergone commissurotomy
Useful - understand more about physiognomy of brain. Importance of corpus callosum connecting hemispheres
Casey et al 2011
Aim - find out if people who had difficulties delaying gratification at 4 still have difficulties 40 years later.
Background - Marshmallow test. Children told if they could hold off eating a marshmallow for 15 mins they could have 2 marshmallows. Done on 4 year old children.
Sample - 59 participants aged 44. (27 low delayers, 32 high)
EX 1 Procedure - Go/No Go task. Cool version = neutral faces. Hot version = happy/fearful faces. Pressed button when correct face showed on screen.
E.g Cool version = Go male neutral face, No go female neutral face
EX 1 Findings - High delayers better at resisting pressing go button than low delayers. Suggests ability to delay gratification is a relatively stable characteristic
EX 2 procedure - 27 participants (11 low delayers, 15 high). Same task but in fMRI scanner.
EX 2 findings - low delayers had less activity in inferior frontal gyrus. Although had more activity in ventral striatum. Opposite for high delayers. Concluded differences between ability to self control/delay gratification related to neurobiological differences
Evaluation