biological

Question 1

sperry aim

Answer 1

to show the independent streams of conscious awareness possessed by each hemisphere

Question 2

sperry Sample

Answer 2

All 11 the participants were epileptics had previously undergone commissurotomies to deal with their severe epileptic convulsions and had fibres at the back of brain severed.

Question 3

visual investigation sperry

Answer 3

Visual Investigation: PPS asked to cover one eye asked to fix gaze on central fixation point image is then projected for 1/10th of a second to either the LVF or RVF.

Question 4

tactile investigation sperry

Answer 4

Tactile Investigation: PS presented with objects in Right hand, in Left hand or both without ability to see what object was the image out from an array of pictures/objects

Question 5

sperry brain part

Answer 5

CORPUS CALLOSUM

Question 6

sperry method

Answer 6

used a quasi experiment in a laboratory with an independent measures design

case study = qualitative data

Question 7

Casey aim

Answer 7

To find out if participants who were low delayers on the marshmallow test at age four and also reported low self control on psychometric measures in their twenties and thirties (low delayers)

Question 8

Casey sample

Answer 8

Participants bhad done Marshmallow test at age four and self control report. Test age four = 562 participants
Self report = 135 participants
59 participants in go-no go trials (27 low delayers, 16 female and 11 males)

Question 9

Casey section a

Answer 9

Longitudinal, quasi experiment. Consent gathered
Experiment one: go/no go task click for happy face or click for fearful face (59 participants)

Cool version: having to press button whenever male or female neutral face appeared

Hot version: having to press button when happy or fearful expression appeared
Experiment 2: MRI scan
Same task in scanner

Question 10

casey results

Answer 10

Both groups performed high in accuracy in Go trials for both hot and cold versions, low delayers showed more false alarms (high = 14.5% and low 10.9%)
Both groups made more errors on No go task (happy or fearful face)

Question 11

Casey conc

Answer 11

Resisting temptation is s relatively stable individual characteristic (similar over 40 years)
‘Hot’ system in central striatum and ‘cool’ In inferior frontal gyrus

Question 12

Blakemore and Cooper aims

Answer 12

Look further at the physiological and behavioural effects of restricted early visual experience on the development of cells of the visual cortex
To consider whether the brain development/plasticity occurs due to nurture rather than nature

Question 13

blak and cop sample

Answer 13

Two cats, one reared in a vertical environment, other horizontal. New-borns at start, 7.5 months old at end

Question 14

blak and cop procedure

Answer 14

• Laboratory experiment, independent measures
  
  • Special cylinder constructed where kitten stood on clear glass platform (with horizontal or vertical stripes varying in width), no corners in there and kitten were collar to prevent seeing its own body
  • Early experience: 1st two weeks in dark room, two weeks 5 hours a day in cylinder (res time back in dark room)
    Exposure to normal environment: Behavioural experiment (initial responses to regular visual world),

Neurophysiological assessment: anaesthetised and temporarily paralysed to measure the electrical firing of individual neurons, cats eyes shown lines of al possible orientations to test responses

Question 15

blak and cop results behavioural assessment

Answer 15

Some cat reflexes normal (eyes dilating regularly)
Temporary deficit (visual placing not shown immediately like reaching out with paws to know if surface was nearby), recovered in 10 hours to normal

Permanent deficit reaching out to touch something very far away/out of reach)
When shown long black rod if horizontal cat sure it shook vertically they wouldn’t react

Question 16

blak and cop results neurophysiological assessment

Answer 16

• In both cats 75% of cells were clearly binocular (both eyes) and in almost every way responded as a normal animal would
  However some orientation responses were abnormal

Question 17

blak and cop conclusions

Answer 17

The brain is modified by nurture/the environment so that the biological system fits the demands of the environment
The unused parts of the innate nervous system don’t simply degenerate but they adapt to match the actual visual input experienced
Both these conclusions demonstrated brain plasticity

Question 18

brain plasticity

Answer 18

the adult human brain can change and adapt to environmental demands

Question 19

Maguire aims

Answer 19

To investigate whether doing a job demands navigational experience and spending more years in that job affect the volume of the hippocampus.

Question 20

Maguire sample

Answer 20

16 right handed male taxi drivers with a mean of 44 years. Their experience as licensed taxi driver varied between 1.5 years and 42 years and their training had taken 2 years. All were medically, physiologically and psychologically healthy.

Question 21

Maguire procedure

Answer 21

Quasi experiment. Matched pairs design.

IV: whether it’s a London taxi driver or a person who doesn’t drive taxis
DV: the volume of a hippocampi including their anterior, body and posterior regions. Correlational analysis between variables of hippocampus volume and time spent as taxi driver

The images were analyzed by counting number of pixels occupied by hippocampus tissue then converting into a volume
MRI scans of all participants taken and analyzed by same experienced individual who was blinded to participants conditions

Question 22

Maguire results

Answer 22

Taxi drivers had significant increase in grey matter volume in both right and left hippocampus

Taxi drivers significant decrease in grey matter volume bilaterally in right and left anterior hippocampus compared to control who had relatively greater grey matter volume in these areas

There was no significant decrease in overall volume of the hippocampi between two groups

Question 23

Maguire conclusions

Answer 23

• There are regionally specific structural differences between the hippocampi of licensed taxi drivers
  
  • There is a an effect of nurture
    Changes from being taxi driver rather than it being people who choose to become taxi driver having pre-existing brain differences

Question 24

sperry and cas simiarlity

Answer 24

Both studies used a quasi experiment method to investigate brain functions.

In Sperry’s experiment the independent measure of the split brain (those with a cut corpus callosum and severed fibers) compared to non-split brain individuals to investigate the independent awareness of the left and right hemisphere. To measure this Sperry used the dependent variable of performance on visual and tactile tasks. This was a naturally occurring independent variable as it these individuals didn’t have the surgery to be studied but to help severe epilepsy and seizures.

Casey used the naturally occurring independent variable of low delayers (those poor at delaying gratification) compared to high delayers (those good at delaying gratification). These individuals were grouped by their performance on the marshmallow task at the age of 4, on self report on self control and the go/no-go task in out of MRI scanner in their twenties and thirties

Question 25

sper and cas difference

Answer 25

The studies gained different types of data from their experimental research.

Sperry obtained qualitative data from the participants written descriptions of results from visual and tactile tasks, mainly being their verbal responses. This allowed Sperry to map laterization of function.

Casey obtained quantitative data from the participants numerical scores on the go/no-go tasks.

Question 26

Casey extent regions of brain

Answer 26

Casey et al. can be seen as adding to Sperry’s research by telling us about the role that other regions of the brain appear to play.

For example, the regions located in the prefrontal cortex that are responsible for delay of gratification. These being the inferior frontal gyrus which is associated with deciding whether or not to resist reward and has been found to have low activity in low delayers. The ventral striatum which is associated with emotion and desires and has been found to have high activity in low delayers

Question 27

prefrontal cortex

Answer 27

deciding whether or not to resist reward

low activity in low delayers

Question 28

ventral striatum

Answer 28

desires and emotions

high activity in low delayers

Question 29

Casey extent increases understanding of diversity

Answer 29

Sperry already suggested that individual differences in the brain lead to observed differences in behavior and Casey et al furthered this understanding by focusing on more specific regions of the brain that contribute to individual differences. They found that the ventral striatum/inferior frontal gyrus are associated with a lack of self-control.

Question 30

mag and blak/cop similarity

Answer 30

scientific - laboratory setting and control

Blakemore Cooper studied early visual experience of kittens, leaving all for 1st two weeks in dark room and two weeks 5 hours a day in cylinder

Maguire analysed images of the brain using a MRI scanner on taxi drivers in London to look at difference in grey matter in the hippocampus

Question 31

mag and blak/cop difference

Answer 31

One difference is the species used as the sample.

Blakemore and Cooper to investigate the impact of early visual experience used a sample that were non-human/animals.

Whereas, Maguire to investigate the plasticity of the hippocampus used humans as their sample.

Question 32

maguire extent increase understanding of brain plasticity

Answer 32

Maguire et al.’s research was able to show that brain plasticity does not only apply to animals such as cats which Blakemore & Cooper found but to humans as well.

Maguire et al showed that excessive use of navigation skills led the brain to adjust and for grey matter in the posterior hippocampi to develop to accommodate this demand, thus demonstrating individual diversity.

Question 33

Maguire extent increases understanding of diversity

Answer 33

Maguire et al.’s research was able to show that brain plasticity does not only apply to animals such as cats which Blakemore & Cooper found but to humans as well.

Maguire et al showed that excessive use of navigation skills led the brain to adjust and for grey matter in the posterior hippocampi to develop to accommodate this demand, thus demonstrating individual diversity. In terms of cultural diversity, there is something unique about the experiences of London taxi drivers in that they have to take ‘the knowledge’, this means there could be differences in hippocampal volume due to culture.