Biopsychology - 6) Split-Brain Research into Hemispheric Lateralisation Flashcards
Hemispheric lateralisation
Idea that each hemisphere of the brain is mainly responsible for certain behaviours, processes and activities
Which hemisphere controls which side of the body?
Right hemisphere controls left side of the body
Left hemisphere controls right side of the body
Lateralisation of emotion
Emotion could be in both hemispheres but there are different types of emotion in each
Davidson et al found that left hemisphere was more active for pleasure and right was more active for negative emotions
Who conducted split brain research?
Sperry (1968)
Aim of Sperry’s research
Examine the effects of disconnecting the brain’s two hemispheres on people’s behaviour
Corpus collosum
Bundle of nerves which connect the two hemispheres together
Allows communication between left and right hemispheres
Participants of Sperry’s split brain research
11 patients who had their corpus collosum severed (split-brain patients) to stop left and right hemispheres from communicating
What is splitting the brain a treatment for?
Epilepsy
What type of experiment did Sperry carry out?
Quasi experiment as the patients already had a split brain
Method of Sperry’s research
Multiple tests carried out where words were shown on left or right side of a screen with a cross in the middle
Participants told to look at cross and words would appear on one (or both) sides for 1/10th of a second
Why were the participants only shown a word for 1/10th of a second?
Prevented both visual fields of the eye being exposed to the information, so only one hemisphere would process it
Results of Sperry’s research (example)
When picture of an object was presented to left visual field (right hemisphere) participants couldn’t name what they had seen
When picture of an object was shown to right visual field they could easily describe what they had seen
Conclusion of Sperry’s research
Hemispheres are lateralised
Negative evaluation of Sperry’s research
Only 11 participants - very niche group of people makes it hard to generalise findings
Years of drug treatment might have affected the way their brains work which could’ve affected the findings
Positive evaluation of Sperry’s research
High validity as experiment was conducted in controlled conditions
Highlights differences between hemispheres
