Lateralisation

• What is hemispheric lateralisation?

  Hemispheric lateralisation is the idea that the two hemispheres of the brain are functionally different and certain processes or behaviours are controlled by one hemisphere rather than the other.
• The right hemisphere processes information from the left side of the body while the left hemisphere processes information from the right side of the body.
• Sperry's experiment into visual recognition of split-brain patients:

  Participants were shown a visual image to either the left or right visual field.

  Images that were shown to the right visual field could be clearly described while images that were shown to the left visual field could not be described and were reported to not be seen.
• Explain the findings of Sperry's experiment into visual recognition of split-brain patients.

  The patient's inability to describe what they had seen in their left visual field was because of a lack of language processing centres in the right hemisphere.

  In the normal brain, information about the image would have been passed from the right hemisphere to the language centres in the left hemisphere via the corpus callosum.
• Sperry's experiment into touch recognition in split-brain patients:

  Participants were shown a visual image and asked to select the object from an array of items behind a screen.

  Images that were shown to the right visual field could be verbally named and selected while images shown to the left visual field could not be verbally named but could be selected.
• Explain the findings of Sperry's experiment into touch recognition in split-brain patients.

  In each case, the patient’s right hemisphere could understand/recognise what the object was, and they could pick it up. However, without being able to send the message to the language processing centres of the left hemisphere the participants could not produce the necessary words associated with the object when the image was shown to the left visual field.
• Sperry's experiment into touch recognition in split-brain patients:

  Participants were shown a different word to both the left and right visual field at the same time.

  Images that were shown to the right visual field could be verbally spoken but not written while images that were shown to the right visual field could be written with their left hand but not spoken.

  This shows that the right hemisphere is superior to the left hemisphere when it comes to drawing.