Lateralisation & Split Brain Research

Question 1

Define the term hemispheric laterilisation (2)

Answer 1

1. 🧠 split into 2 symmetrical halves called left/right hemisphere
2. idea that 2 DIFFERENT hemispheres are responsible for different mental processes

eg LHS controls right side of body and is responsible for language

Question 2

Explain the function of LHS

Answer 2

1. recieves info from right visual field(RVF)
2. controls right side of body

Question 3

Explain function of RHS

Answer 3

1. recieves information from LEFT VISUAL FIELD
2. controls LEFT SIDE OF BODY

Question 4

Define CONTRALLTERAL WIRING (2)

Answer 4

1. TWO hemispheres work together by communicating through corpus callosum
2. not all functions of brain is laterilised

Question 5

Many Functions are not laterilised give three examples and why

Answer 5

• 1. VISION
  2. MOTOR
  3. SOMATOSENSORY
• occur in BOTH hemispheres

Question 6

What is the LHS responsible for? (2)

Answer 6

1. language as two main centres Broca’s area responsible for speech production
2. Wernicks area responsible for understanding language are located in LHS

Question 7

What is RHS responsible for ? (2)

Answer 7

1. recognition of faces places, objectives and creativity 👨‍🎨
2. only produce rudimentary words and phrases but contributes to EMOTIONAL CONTEXT of what is being said

Question 8

whats RTS

Answer 8

P - 😁 Sperry using split brain patients with a severed corpus collosum

E - found that ppts shown image of object to right visual field patients could name it verbally

> could identify object through pointing

E - supports idea that 🧠 is lateralised
and hemispheres responsible for language abilities

L - therefore supports theory of hemispheric laterilisation

Question 9

Why has Sperry’s R been criticised ☹️

Answer 9

P - Individual differences in how laterilised ppts brain was

E - degree which corpus collosum was severed varied GREATELY

some having greater disconnection between two hemispheres than others

L - R may not be measuring effects of laterilisation effectively > reduces ⬇️ IV of

R therefore may not be appropriate for explaining hemispheric laterilisation not

Question 10

How can HTS be discussed?

Answer 10

may not be appropriate explanation of how brain functions as R suggests brain has plasticity and rewires itself to compensate for any loss of function

Question 11

WHATS RTC HEMISPHERIC LAT

Answer 11

P - case study EB

E - EB suffered from brain damage that resulted of removal of LHS

E - despite this after ⏱️ managed to regain some if his lang abilities which could not be possible if brain was completely lateralised (and only left responsible for language)

L - demonstartes that lang must be in >1 area of brain

therefore ❌arguing against laterilisation of function in brain

Question 12

WHATS D point for EB

Answer 12

P - lacks pop val

E - not be appropriate to Gf on laterilisation of function to typical pop
as unique cases where brain damage may have affected way in which brain damage

L - these are unique case studies where brain damage may have affected the way in which the brain junctions and some individuals may be able to process language in the right hemisphere. some R has suggested that language is not solely lateralised to the left hemisphere but is found in the DOMINANT CEREBRAL HEMISPHERE > commonly found to be opposite to the DOMINANT HANDEDNESS

L- more research is needed with more diverse samples before firm conclusions on the lateralisation of language is possible.

Question 13

Define Split brain (2)

Answer 13

1. split brain patients have had surgery (normally to treat epilepsy) to cut area that connects two hemispheres of 🧠

(CORPUS CALLOSUM)

2. Surgery may relieve epilepsy has major side effects

> two hemispheres become functionally seperate as act as 2 seperate independent brains

Question 14

What is the aim of split brain R

Answer 14

1. to investigate effect of severing connection between two hemispheres of 🧠

(corpus collosum) on functioning

Question 15

What method and sample did sperry use?

Answer 15

1. Natural experiment
2. 11 I’s who had their corpus collosum severed due to surgery

Question 16

How/Procedure is split brain tested?

Answer 16

1. ppts sit infront of screen whilst fixating gaze on spot of middle of a screen
2. ppts then presented w an image of LVS or RVS for 1/10th of second

so not enough time for other visual field to switch focus to visual image

Question 17

What were the findings?

Answer 17

1. If visual info presented on RVS then object can be named verbally
2. objects seen only LVS then only identified via pointing out 👉🏼but cannot be named by ppt

Question 18

what did sperry conclude/

Answer 18

1. two hemispheres of brain have different abilities and functions

ONLY LEFT PRODUCES LANG

2. right hemisphere recall + identify information but cannot verbalise this

Question 19

Give a strength of Split Brain Research

Answer 19

P - controlled environment

E - uses objective empirical techniques such as controlled lab setting

E - R found that helped identify which hemisphere is responsible for which task eg split brain R patients only say what saw in RVF

L - increases overall IV raising psychs scientific status

Question 20

How can split brain R be discussed?

Answer 20

P - individual differences in participants in terms of the relation to how lateralised their brain was
.
E - The degree to which the corpus callosum was
severed for each patient varied greatly
.
E = As some patients had a greater disconnection
between the two hemispheres than others.

• This is a weakness because the research may not be measuring the effects of lateralisation effectively which reduces the IV of split brain research

Question 21

Give a weakness into split brain research

Answer 21

P - casual rs hard to establish

E - bh of sperrys split-brain ppts compared to neurotypical group ehere none of control group had epilsept

E- acts as major confounding variable as difference in two groups could have been due to epilepsy rather than split brain

as epilepsy may have caused unique changes in brain that may have influenced findings of how brain is laterilised

L - diff to establish whether ppts cognitive abilities and lateralisation are due to split brain or epilepsy

lowering IV of split brain R

Question 22

How does holistic theory differ from LOC and HTS

Answer 22

1. Before investigations into LOC and laterilsation scientists believed all parts of brain worked together when processing information