Hemispheric Lateralisation and Split Brain Research

Question 1

what is meant by hemispheric lateralisation?

Answer 1

idea that the two halves of the brain function differently. the right controls the left and left controls right.

Question 2

what is the role of the left hemisphere?

Answer 2

language centre. controls right hand and receives information from right visual field.

Question 3

what is the role of the right hemisphere?

Answer 3

focuses on visuospatial tasks, controls left hand and receives information from left visual field.

Question 4

one strength of hemispheric lateralisation is….. (AO3)

Answer 4

lateralisation in connected brains.

fink et al: PET scans to identify which brain areas were active during visual processing task. global elements processed by RH and finer detail by LH.

shows lateralisation part of connected brain as well as split brain.

Question 5

one limitation of hemispheric lateralisation is… (AO3)

Answer 5

idea of LH analyser and RH synthesiser may be wrong. there are different functions in RH and LH but research suggests that people do not have a dominant side of the brain which creates a different personality. (Nilsesen et al)

Question 6

what is split brain research into?

Answer 6

people who have had an operation severing connections between RH and LH (corpus collosum) used to reduce epilepsy.

research shows how hemispheric function

Question 7

describe Sperry’s research procedure

Answer 7

Quasi experiment with 11 PPS. these PPS already had procedure to split hemispheres done, limiting ethical issues.

PPS had to stare at a fixation point on a screen for 1/10s

Question 8

describe Sperry’s findings

Answer 8

object shown to RVF (LH) cannot name object but can select with left hand.

pinup picture shown to LVF, emotional reaction but report nothing.

Question 9

describe Sperry’s conclusions

Answer 9

lateralised brain, LH verbal and RH silent but emotional.

Question 10

support for split brain research (AO3)

Answer 10

Gazzangia (luck et al): showed split brain PPS perform better than controls on certain tasks eg. faster at identifying odd one out in an array of objects.

in normal brain LH cognitive strategies watered down by inferior RH. supports sperry’s earlier findings.

Question 11

generalisation issues with split brain research (AO3)

Answer 11

causal relationships hard to establish.

sperry’s research compared to a neurotypical control group. issue as none of the PPS in control group had epilepsy. (major confounding variable)

any difference could be due to epilepsy not split brain.