Hemispheric lateralisation Flashcards
What is hemispheric lateralisation?
The idea that the two hemispheres of the brain (left and right) have specialised functions
What are the left hemispheres main functions?
→ Language - Broca’s area and Wernicke’s area
→ Receives input from the right visual field and it controls the actions of the right side
What are the right hemispheres main functions?
→ Visual imagery
→ Spatial/motor
→ Receives input from the left visual field and it controls the actions of the left side
→ Left handed people tend to have language in the right hemisphere
What are split brain patients?
Individuals who have suffered severe epilepsy and as a last resort treatment have had their corpus callosum cut.
This disconnects their right and left hemispheres.
What type of experiment was Sperry’s study?
Quasi experiment
What was the experimental design of Sperry’s study?
Independent measures
What was the independent variable of Sperry’s experiment?
Whether the individual had a split brain or not
What was the dependent variable of Sperry’s study?
The individual’s performance on visual and tactile tasks
Who were the participants in Sperry’s study?
11 participants - all epileptic and had previously had undergone commissurotomies to deal with their severe epileptic convulsions
What was Sperry and Gazzaniga’s aim in their research?
The aim of their research was to examine the extent to which the two hemispheres are specialised for certain functions
What was Sperry and Gazzaniga’s method?
An image/word is projected to the patient’s left visual field (which is processed by the right hemisphere) or the right visual field (which is processed by the left hemisphere). When information is presented to one hemisphere in a split-brain patient, the information is not transferred to the other hemisphere (as the corpus callosum is cut)
What were the tasks in Sperry and Gazzaniga’s study?
In thedescribe what you seetask, a picture was presented to either the left or right visual field and the participant had to simply describe what they saw.
In thetactile test, an object was placed in the patient’s left or right hand and they had to either describe what they felt, or select a similar object from a series of alternate objects.
Finally, in thedrawing task, participants were presented with a picture in either their left or right visual field, and they had to simply draw what they saw.
What were the findings from Sperry and Gazzaniga’s study?
Words or images presented to the right visual field could be verbally identified
Words or images presented to the left visual field could not be verbally identified but the individual could draw what they saw
These findings tell us that language functions in the left hemisphere
→ Supports the idea of hemispherical lateralisation
