Biopsychology: Hemispheric Lateralisation

Hemispheric Lateralisation Spec Pt 5 including studies and evaluation - A-Level Content

What is the Corpus Callosum

thick, wide bundle of nerval connections linking Left and right hemisphere

What is hemispheric lateralisation

idea that two halves of the brain are functionally different and certain processes and behaviours are controlled by one hemisphere or another

What is the left hemisphere generally lateralised to

Processing language eg Broca and Wernickes areas

What is the right hemisphere generally lateralised to

Processing visual info, imagination, creativity and spatial info

Who conducted split brain research

Sperry (1968)

What is a commissurotomy

the severing of the corpus callosum in order to treat epilepsy

Who were the participants in Sperrys study

11 patients with severed corpus callosum

What was the study aim based on

the idea of contralateral control

What is contralateral control

info from Left visual field goes to the right hemisphere and info from right visual field goes to the left hemisphere

What was the aim of Sperrys research

to Study how split hemispheres deal with speech and vision

What was the first Task in Sperrys research

Describe what you see - stare at the dot in centre - image presented to RVF or LVF and patient says what they saw

What was the finding from Task 1

images shown to the LVF (RH) patients couldn’t say what they saw but could draw it with their left hand

images show to the RVF (LH) patients can say what they saw

What was the second task in Sperrys research

Tactile Task - objects placed in the right or left hand and patients asked what it is

what was the finding of task 2

objects in the right hand (LH) - patients can say what is in their hand

objects in the left hand (RH) - patients cant say what is in their hand but can find the object most associated with it

what is the conclusion from Sperrys findings

shows that certain functions of the brain are lateralised and shows LH is verbal and RH is emotional

Give one example of research support for Sperrys findings

Michael Gazzaniga showed split brain people perform better than normal patients in tasks like odd one out

Give one other strength of Sperrys research

the methods are well controlled which means its replicable and so can be tested for consistency therefore has high reliability

Give an example of research that shows a limitation of Sperrys findings

Nielson showed that while each hemisphere had specific roles in different tasks there is no evidence of either one bieng dominant

Give one other limitation of Sperrys findings

the limited population of possible participants means that it is hard to generalise these findings because all patients were already neurodivergent because of their epilepsy