🟢 Biopsychology - Lateralisation & Split Brain

Question 1

What is the corpus collosum

Answer 1

Structure between the 2 hemispheres, allows communication between the left and right hemisphere

Question 2

What is split brain research

Answer 2

Research on people who have had their brain split in half - severing the corpus callosum

Question 3

What is lateralisation

Answer 3

The idea that the 2 halves of the brain are functionally different

Question 4

Who carried out famous studies on split brain

Answer 4

Sperry and Gazzaniga in the late 1960s

Question 5

Sperry (1968) AIM

Answer 5

to examine the effects of disconnecting the brains 2 hemispheres on people’s behaviour

Question 6

Sperry (1968) METHOD

Answer 6

• 11 participants, natural experiment
• hemispheres all disconnected by severing Corpus Callosum
• apparatus used which could present information to 1 hemisphere
• sat at table, visual stimuli presented to 1 hemisphere
• screen divided L+R visual fields and stimuli projected for 1/10th second too fast for any eye movements
• test on vision, emotion, olfaction, consciousness

Question 7

Sperry (1968) RESULTS

Answer 7

• disconnecting the hemispheres does not affect participants ordinary behaviour, intelligence or personality
• it does affect short term memory, orientation and fatigue
• shows hemispheres have different abilities and functions
• one hemisphere doesn’t know what the other has seen or felt

Question 8

Sperry (1968) CONCLUSION

Answer 8

SUPPORTS LATERALISATION

the 2 hemispheres have different functions and that split brain patients have ‘divided consciousness’

Question 9

Sperry (1968) EVALUATION

Answer 9

✅ highlights difference between 2 hemispheres
✅ provides insight to normal brain functions

❌ natural experiment meaning Sperry could not manipulate which group participants where in and no control group
❌ small sample, rare, limited generalisation

Question 10

What hemisphere specialises language

Answer 10

Left hemisphere

Question 11

What does the hemisphere specialising in language depend on

Answer 11

Handiness,

95% of right handed participants specialised language on left hemisphere

70% left handed participants specialised language on right hemisphere

Question 12

What is the Wada test

Answer 12

Test to determine which hemisphere in the brain specialises in language

Question 13

Process of Wada test

Answer 13

Anaesthetic injected into carotid artery on one side of the head. ( anaesthetic on one hemisphere).

P then reads aloud but was disrupted 90% of people.

Question 14

Evidence of left hemisphere specialising language, aphasia

Answer 14

Language aphasia occurs more as a result of damage to left hemisphere than right hemisphere

Question 15

Sperry (1968), naked person experiment

Answer 15

• presented naked person to split brain patient’s left visual field
• Left visual field —- right hemisphere
• reported that they saw nothing however did smile and giggle, embarrassed
• suggests right hemisphere is lateralised for emotional language

Question 16

Evaluation of lateralisation

Answer 16

✅ control of extraneous variables in experiments
❌ small sample, not generalise able
❌ difference between 2 hemispheres may have been over emphasised, may have shown demand characteristics, lack ecological validity
❌ more recent research shows right hemisphere couldn’t process even basic language (Turk et al 2002)