split brain research

Question 1

hemispheric lateralisation

Answer 1

brain’s two hemispheres are responsible for different functions - function is lateralised

left hemisphere - language and speech

right hemisphere - visual-motor tasks

Question 2

sperry and gazzaniga

Answer 2

split brain patient fixates on dot in centre of screen while info is present to either left or right visual field.

patient then asked to respond with either their left hand controlled by right hemisphere or right hand controlled by left hemisphere or verbally which is controlled by left hemisphere, without being able to see what their hands were doing

e.g if patient was flashed pic of dog to right visual field and asked what they saw they would answer dog. however, if picture of cat was flashed to left visual field patient would say they saw nothing as info from left visual field is processed by right hemisphere but it has no language centre - can’t respond verbally

Question 3

split brain research findings

Answer 3

left hemisphere is responsible for speech and language

right hemisphere specialises in visual-spatial processing and facial recognition

research suggests connectivity between different regions is as important as operation of the different parts

Question 4

evaluation - language may not be restricted to left hemisphere

Answer 4

gazzaniga - some early discoveries from split brain research has been discomfirmed by more recent discoveries

damage to left hemisphere was found to be far more detrimental to language function than was damage to right. however, case study of J.W who developed capacity to speak out of right hemisphere resulting in ability to now speak about info presented to left or to right brain challenges claim that right hemisphere is unable to handle even the most rudimentary language

Question 5

evaluation - limitations of split brain research

Answer 5

andrewes - many split brain studies have from 1-3 PPs
in some cases, conclusions were drawn from individuals who either had confounding physical disorder that made split brain procedure necessary or had less complete sectioning of the hemispheres than was originally believed

patients who had procedure without confounding factors are rarely encountered in sufficient numbers to be useful for research

Question 6

evaluation - related to increased neural capacity

Answer 6

by using only one hemisphere to engage in particular task, this leaves other hemisphere free to engage in another function

rogers et al - in chickens, brain lateralisation is associated with enhanced ability to perform 2 tasks simultaneously - finding food and being vigilant of predators - provides some evidence that brain lateralisation enhances brain efficiency in cognitive tasks that demands simultaneous but different use of both hemispheres

despite this evidence it can’t be applied to humans as there’s little empirical evidence provided to show lateralisation has any advantage to brain functioning in humans