split-brain research into hemispheric lateralisation

Question 1

what is hemispheric lateralisation

Answer 1

the idea that 2 halves of the brain are functionally different and that certain mental processes and behaviours are mainly controlled by one hemisphere rather than the other

Question 2

split brain studies

Answer 2

Sperry’s studies involved a unique group
- their corpus callosum and other tissues that connect the 2 hems were cut
- allowed Sperry to see the extent to which the 2 hems were specialised for certain functions and if they performed tasks independently

Question 3

procedure

Answer 3

1. an image or word would be projected to an individuals right visual field
2. the same or diff image was projected to the left visual field
   - presenting the image to one hem meant the info could not be conveyed to the other

Question 4

key findings

Answer 4

• describing what you see
• recognition by touch
• composite words
• matching faces

Question 5

describing what you see

Answer 5

when an image was shown to right side, they could easily describe what was seen
- if same image was shown to the left, they could not describe what was seen and typically reported that there was nothing there

Question 6

why was this found

Answer 6

bc lack of language centres in the right hemisphere, so they cant describe what they saw even if they know what it is

Question 7

recognition by touch

Answer 7

while they could not name objects projected to the left, they could select a matching object using their left hand
- could also select an object closely related to the object shown to left visual field
> eg. pic of cig shown, picked up ashtrayc

Question 8

composite words

Answer 8

if 2 word presented simultaneously, one on either side, they could:
- select the object shown on the left w their left hand
- say the word seen on the right out loud

Question 9

matching faces

Answer 9

right hem dominant in terms of recognising faces
- when asked to match a face from a series of other faces, pic processed by left eye was consistently selected
- picture presented to the right eye was ignored
- when a composite pic if 2 diff halves of a face was shown, the left hem dominated in terms of verbal description and right hem in selecting a matching picture

Question 10

supporting evaluation for split-brain research

Answer 10

1. strengths of methodology
   2.

Question 11

strengths of methodology

Answer 11

E - ppt asked to stare at a given point where an image would be projected for 1/10 sec
E - split-brain ppl won’t have time to move eyes across image to spread info to both sides of brain
- allows Sperry to ensure only one hem was receiving info
L - made high use of standardised procedures and provides strong internal validity

Question 12

opposing evaluation for split brain research

Answer 12

1. issues with generalisation

Question 13

issues with generalisation

Answer 13

E - unusual and small sample, only 11 ppts and all had history of epileptic seizures
E - may cause unique changes in the brain that could have influenced the findings
L - provides valuable insights into hem lat but caution needed when generalising to neurologically typical people