6. BIOPSYCHOLOGY (SPLIT-BRAIN RESEARCH / HEMISPHERIC LATERLAISATION) Flashcards
What is hemispheric lateralisation in the brain?
Hemispheric lateralisation refers to the idea that the two hemispheres of the brain are functionally different, with specific mental processes and behaviours primarily controlled by one hemisphere over the other.
How does hemispheric lateralisation affect speech production and facial recognition?
Speech production is lateralised to the left hemisphere (Broca’s area), while facial recognition is lateralised to the right hemisphere.
What is the role of the corpus callosum in the brain?
The corpus callosum connects the two hemispheres, allowing communication between them and enabling the sharing of information, such as visual stimuli processed by both sides.
How did split-brain research arise?
Split-brain research came about when surgeons cut the corpus callosum in patients to treat epilepsy, which allowed researchers to study the functioning of each hemisphere independently
What is the split-brain procedure?
The split-brain procedure involves presenting stimuli to each visual field separately. In normal brains, the corpus callosum allows the two hemispheres to share the information. In split-brain patients, this sharing is not possible.
What happens when a split-brain patient sees an object in their right visual field?
The patient can describe the object, as it is processed by the left hemisphere, which controls language.
What happens when a split-brain patient sees an object in their left visual field?
The patient may report seeing nothing because the right hemisphere processes the information but lacks the language centre to describe it. The left hemisphere doesn’t receive the information.
What did Sperry & Gazzaniga’s study show about the left and right hemispheres?
Their study demonstrated that the left hemisphere controls verbal tasks, while the right hemisphere is more adept at spatial and non-verbal tasks, like face recognition.
How did split-brain patients perform on object recognition tasks involving the left visual field?
They couldn’t verbally describe what they saw, but could select a matching object using their left hand, as the right hemisphere processes this visual information.
What did Sperry & Gazzaniga’s study reveal about face recognition?
The right hemisphere was dominant for face recognition, as split-brain patients could consistently select the correct face when it was presented to the left visual field (processed by the right hemisphere).
What is one strength of Sperry & Gazzaniga’s split-brain research?
The research is a quasi-experiment with high control, as researchers studied patients with naturally occurring hemisphere deconnection, providing evidence for hemispheric lateralisation.
What is a limitation of Sperry & Gazzaniga’s split-brain research?
The study has low population validity because the sample was small (11 split-brain patients), and the participants’ epilepsy may have caused brain changes not seen in other people.
What is a strength of the hemispheric lateralisation theory?
The case study of ‘Tan’ supports the theory, as it shows that the left hemisphere (Broca’s area) is responsible for speech production
What is a limitation of the hemispheric lateralisation theory regarding language?
Language is not always restricted to the left hemisphere in all people; left-handed individuals may have language centres in either hemisphere or both.
How does age affect hemispheric lateralisation?
Lateralisation appears to change with age. For example, younger individuals tend to have more lateralised brain functions, while older adults may rely more on both hemispheres due to age-related cognitive decline.
