Lateralisation and split brain research

Question 1

Hemispheric lateralisation

Answer 1

The two hemispheres of the brain are functionally different and that certain processes are governed by a specific hemisphere of the brain

Question 2

Left Hemisphere

Answer 2

*Controls right side of the body.
*Understanding written language/hearing.
*Right visual field.
*Speech
*Logical thinking.

Question 3

Right Hemisphere

Answer 3

*Controls left side of the body.
*Creativity.
*Spatial awareness.
*Left visual field.
*Recognising faces.
*Musical ability

Question 4

Left Visual Field

Answer 4

*Information received in the LVF is processed in the right hemisphere.

Question 5

Right Visual Field

Answer 5

Information received in the RVF is processed in the left hemisphere.

Question 6

Corpus Callosum

Answer 6

Hemispheres are connected via the corpus callosum and therefore can share information

Question 7

Split Brain Patients

Answer 7

Commissurotomies procedure.
Involves cutting the corpus callosum to prevent epileptic seizures

Question 8

Split Brain Context

Answer 8

*1950s
*Sperry developed the split brain procedure for animals to prove hemispheric dominance in the brain.
*It was discovered that the procedure could assist with helping epileptic seizures.

Question 9

Sperry & Gazzaniga (1968) - Procedure

Answer 9

*11 split-brain patients who had the surgery.
*Participants sat in front of a screen with hand holes to cover their hands.
*Told to fixate on one position on the screen.
*Images flashed for 1/10th of a second on either the left or right visual field.

Question 10

Sperry & Gazzaniga (1968) - Results

Answer 10

When an image was displayed in the RVF it was processed by the left hemisphere, therefore participants could describe the image but not draw it.

When an image was displayed in the LVF it was processed by the right hemisphere, therefore participants could draw what they say (left hand) but not describe it.

Question 11

AO3

Answer 11

• Language may not be restricted to the left hemsisphere
• Lateralisation changes with age
• Evolutionary Benefits

Question 12

Language may not be restricted to the left hemsisphere

Answer 12

Turk et al (2002)
*JW developed the capacity to speak using his right hemisphere.
He can now use both the left and right hemisphere for language production.

Question 13

Lateralisation changes with age

Answer 13

Szaflarski (2006)
*Found that in children and adolescents there was left hemisphere dominance for language, but this decreased over time the older the participants were.
*This may be a compensation strategy due to age related decline of functioning.

Question 14

Evolutionary benefits

Answer 14

*Rogers et al (2004)
*Found in chickens. brain lateralisation is associated with an enhanced ability to perform two tasks simultaneously (finding food & being aware of predators).
*Shows that brain lateralisation enhances brain efficiency in cognitive tasks.

*However, there is very little evidence for this in humans.