Biological Area Flashcards
What are the key assumptions about the biological area?
Left side is for language and right side is for creativity
Things in left visual field go to right side of brain vice Versa
What is contralateral control
Control of opposite side of brain
What is lateralisation of function
Each hemisphere has own function
What were the aims of maguires study
- investigates differences in brains between people who extensively use spatial navigation and those who don’t
- further investigate functions of hippocampus
What research method and experimental design was used in maguires study
Matched groups-age gender dominant hand
Quasi and correlation
Sample from maguires study
Experimental group: 16 right handed male London taxi drivers, 32-62 years old, had 1.5 to 42 yrs experience, were all deemed medically and psychologically healthy
Control group: 50 MRI scans of right handed males aged 32-62 from a data base
What are strength and weakness of sample by maguire
Range of experience, participant variables are controlled-increase validity
Can’t generalise to females or left handed taxi drivers-decrease in population validity
What was the procedure in maguire
Taxi drivers got MRI scan, to get image of structure of brain
MRI’s were all analysed
What were the two techniques used to analyse the MRI scans
Voxel based morphometry and pixel counting
What did VBM and pixel counting give
VBM gave a 3D measurement of volume of the grey matter
Pixel counting gave 26 slices of brain, to give a 2D measurement of area of grey matter
Who analysed the MRI scans in maguires study
Someone who was blind to the experiment (didn’t know who the mri scan belonged to)
What was the results of VBM analysis maguire
There was an increase in grey matter volume in the posterior hippocampus and a decrease in volume of anterior hippocampus in the taxi drivers
What was the findings of the correlational study on whether there was a relationship between time as taxi driver and hippo amp all volume
Positive correlation between the right posterior hippocampus area and time spent as a taxi driver
Negative correlation between volume of anterior hippocampus and time spent as taxi driver
What are the conclusions of maguires study
Evidence of regionally specific structural differences between hippocampi of licences London taxi drivers and the control, and correlational analysis confirmed the difference is related to environmental stimulation
What does the anterior and posterior, left and right hippocampus do
Posterior-long term/previously learned
Anterior-short term/newly learned
Right-mental maps
Left-memories and events
How ethical was maguires study
Extremely, didn’t break any guidelines, informed consent etc
Does maguires study have internal reliability
Lab experiment so highly controlled, so standardised and replicable
Does maguires study have concurrent validity
Blakemore and cooper brain plasticity, shows the same results, brain structure adapts to the environment
Does maguires study have ecological validity
MRI is not every day occurrence, however hippocampi size can not be falsified, nondemand characteristics so participants can’t change the size of it, so yes high ecological
Does maguires study have population validity
Only for right handed males, not for females or lefties
Species specific as brain functioning is same for everyone
Is maguires study ethnocentric
Yes-only represents London taxi drivers due to knowledge test
No-species specific behaviour, as brain plasticity is in response to spatial demands
How is maguire related to biological area and the key theme of brain plasticity
Investigates neuroplasticity in brains of humans, demonstrated plasticity of hippocampus and mri scan gave biological data
Fully developed adult brain could change and adapt to environmental demands, neuroplasticity explained as hippocampus having to adapt to enable taxi drivers to meet demands of job
How does maguires study link to the nature nurture debate
Nurture supported
Shows that spatial knowledge is improved with experience, you aren’t born with good spatial knowledge, it develops as you use it more
Why does maguires study link to psychology as a science
Highly controlled lab, can replicate, and objective method of measurement (MRI)
How does maguire link to usefulness
Developed further understanding of how brains can adapt
Allows for more advances in brain analysis and treatment/diagnosis
What is a similarity between blakemore and maguire
Both support nurture debate Highly controlled labs Aimed to get objective data-MRI and neurophysiological measures Quantitative data Both ethical
What’s a difference between maguire and blakemore
One on cats one on humans
Maguire is snap shot, blakemore was longitudinal
Maguire hippocampus blakemore visual neurones
What’s the aim of sperry
Investigate the effects of de-connection and show that each hemisphere has different functions; to map lateralisation of brain function and show that information in one side of brain is not accessible to other side
What’s the method and design of sperry
Quasi experiment comparing split brain subjects and normal subjects in laboratory subjects
Sperry sample
11 participants who had experienced commissurotomy prior to study
Opportunity sample
All had severe epilepsy
What was procedure of sperry
Sat at table with hands out of site, visual information shown to left or right visual field for 1/10th of second and tactile information shown to either one of hands or both
What was the visual investigation of sperry
Showing one stimulus at a time to one visual field, or showing two stimuli simultaneously to two different visual fields
What was the tactile investigations sperry
Subjects hand hidden from view,
- asked to find object corresponding with what they had seen on screen
- asked to say what they could feel in hand
- asked to point to what they could feel in hand
What were the results of visual investigations
- if shown to right visual field, subject able to say what they seen, could identify it from array of pictures, could find it with right hand
- if shown to left visual field, unable to name it, but can draw it with eyes closed, could find it by pointing at pictures and could find it with left hand
Results of tactile investigations
- Same irrespective of whether object was held by one hand at a time or by both hands simultaneously
- if out in right hand can identify by name, if in left hand no conscious awareness of it however would be able to find it in bag with array of objects
Results of right hemisphere
Right hemisphere carry out simple math problems
Left hand sort objects in size, texture, shape
When see geometric shapes, giggle when picture of nudity shown, non verbal response suggest right hemisphere has second conscious entity
Conclusion of sperry
Gave support to idea that brain consists of two seemingly independent hemispheres each with its own consciousness
Discuss ethics of sperry
No deception
Consent given
Neither harmed or unduly stressed
Discuss validity of sperry
- low due to small sample, within that sample there was “striking modifications and even outright exceptions” suggesting many individual differences in 11 people, must be vast differences in normal brains
- can’t generalise to normal brains as they only tested split brain participants
- low ecological, because normal situations both eyes open and things don’t flash for 1/10th of second, tactile tasks more ecologically valid as we do root about in bags etc
Discuss reliability of sperry
“Outright exceptions” challenge the reliability
Sperry found trends and similarities in the lateralisation of brain function in split brain participants suggest some reliability
Is sperry ethnocentric
Brain lateralisation is affected by anatomy and physiognomy of brain can argue it’s not ethnocentric as investigating species specific behaviour
Individual differences were noted and exceptions to the rule. Environment and culture influence how brain develops, non western raised people may experience differences
Why does sperry link to science
Controlled lab experiment, fulfil criteria of theory, control, evidence and replication
Is possible to prove false with another fresh sample and replicating the study it is falsifiable
Sperry link to usefulness
Revealed in proton W of corpus callousness as pathway for internal communication between two sides of brain
Why does sperry link to freewill/determinism
Suggest position of biological determinism, undergoing commissurotomy mean split brain patients for example can’t name objects they touch with left hand out of sight, inability to do this is determined by physiological factors
Why does sperry fall into biological
Investigating regions of brain and lateralisation of brain function, demonstrated importance of corpus callosum as communication pathway between hemispheres providing evidence of different functions of each hemisphere
Aim of Casey
See if low delayers on marshmallow test age 4 still struggled in adulthood
Examine activity In areas of the brain thought to be associated with ability to resist temptation
- low delayers show more errors on go/no-go task if stimuli were hot (rewarding emotional faces) than high delayers
- lowdelayers show lower activity in right prefrontal cortex suggesting lower inhibition
- low delayers show increased activity in central striatum where positive cues are processes than high delayers
The sample in Casey go no-go task
59
27 low layers (16 female, 11 male)
32 high delayers (20 female, 12 male)
How did Casey get final sample
Longitudinal study
Group of participants from marshmallow test completed self control test on self report inventory in 20s and 30s-135 participants
117 Potential participants contacted and 59 agreed
What was experiemnt 1 Casey
- self control measured by go no-go task
- all 59 did 4 tasks
- has to press a button when see certain stimuli
- hot stimuli, cold stimuli
- laptop delivered to their home, face appeared for 500ms, instructions given,
What were the 4 go no go tasks
- cool version male neutral face
- cool version female neutral face
- hot version happy face
- hot version fearful face
All target faces appeared 120/160
What was experiemnt 2 Casey
Investigate regions of brain that implicated self control
- completed 48 trials of go/no-go in fMRI
- 27 out of 59 agreed to do this
- one participants results removed due to poor task performance
- 15 high delayers (10 female), 11 low delayers (4 female)
Result of experiment 2 Casey
Low delayers showed more false alarms in go trials
Low delayers showed lower activity in right inferior gyrus than high delayers
Low delayers showed higher activity in ventral striatum when happy faces were no-go stimuli
Casey conclusions
- resisting temptation is relatively stable individual characteristic shown by 40 year study low delayers aged 4 had more difficulty suppressing responses to socially alluring cues (happy face)
- suggest delay ability it is hindered by alluring cues not problem with cognitive control
- hot system is ventral striatum, cool system is inferior frontal gyrus
Discuss ethics of Casey
Consent
No deceptions
The participant attrition shows the use of withdrawal
Discuss validity of Casey
- standardised instructions and highly controlled-fMRI so high design validity
- low population validity, due to subject attrition the sample is not as generalisable as the original sample, those who continue to volunteer may have similar characteristics, only 4 female low delayers in experiment 2
- low ecological as the go no go tasks have no equivalent in every day life, being in a fMRI is not everyday occurrence could have impacted performance if they didn’t like being in one
Discuss reliability of Casey
It’s longitudinal so Not easy to replicate as study took 40 years, would have to follow participants from age 4
However did start with fairly large sample for experiemnt 1 and showed consistent results
Is Casey ethnocentric
No as it’s species specific as self control and deferred gratification is affected by anatomy and physiognomy
Yes only conducted in America and being raised in culture of capitalism and consumerism which puts temptation in people more than other culutr w might mean there may not be as many low delayers in other countries
Why does Casey link to science
Laboratory experiemnt
Used scientific equipment-fMRI
Theory, control, evidence and replication
Casey nature/nurture
Shows the stability of lack of self control over time-nature
Nurture-watch and learn from those who resist temptation, the rewards we get from environment for resisting or not
Why Casey fall into biological
Investigates whether specific regions of brain impact our ability to resist temptation of rewarding stimuli, specifically, providing empirical evidence that our biology has significant part to play in ability to defer gratification
Similarity between sperry and Casey
Highly controlled labs
Both conducted ethically
Difference between Casey and sperry
Casey studied normal brain, sperry studied abnormal brain
Casey longitudinal, sperry snapshot
Casey has scientific equipment to observe functioning, sperry had to infer from what participants could and couldn’t do
Aim of blakemore and cooper
Limit visual experience of kittens to one orientationand to compare the behavioural consequences of this restricted visual experience.
To investigate neurophysiological effects on neurones in kittens visual cortex
Blakemore and cooper procedure
- from birth kittens housed in complete darkness
- from aged 2 weeks, exposed to either only vertical orientated or horizontal orientated environment
- exposure ended when 5 months old and kittens had passed through critical period for visual development
Behavioural results of blakemore and cooper
- Cats removed from dark room for several hours
- when first exposed to well lit room both cats showed visual deficit
- no startle response
- no visual placing
- moved around by touch
- 10 hours after exposure deficits disappeared and began to show visual placing and startle responses
- visual tracking remained clumsy and jerky and often bumped into things
What two test conducted showed the differences between the two kittens
- rod used to play with kittens, only seen if it was presented in the same orientation as the stripes in the cylinder
- Perspex sheet with stripes in same orientation as cylinder would result in startle response when presented to cat
What were the neurophysiological findings of blakemore and cooper
Normal cat has even balance of horizontal and vertical neurones
Horizontally raised kitten had no neurones in vertical orientation and vice verse for other cat
Blakemore and cooper conclusions
“Evidently the visual experience of animals in early life has modified their brains and there are profound perceptual consequences”
-development of brain responds to environment that’s experienced
Discuss ethics of blakemore and cooper
- was conducted within guidelimes laid down by home offic for studies conducted on animals
- no long lasting effects however initial deprivation was cruel
Discuss validity of blakemore and cooper
High levels of control-cylinder same shape and height, wore a cone
Behavioural and neurophysiological measures show concurrent validity
Discuss reliability of blakemore and cooper
Detailed descriptions of procedure it would be possible to repeat to get test re-test reliability
Small sample may be flukes?
Is blakemore and cooper ethnocentric
Study on cats so species specific, but can not be generalised to any other animal/human
Why does blakemore link to nature/nurture
Showed development of visual orientation in cats was products of both nature and nurture
Nature provide kittens with neurones of proffered orientations
But restricted visual environment had strong effect on how their brains developed
Results of experiemnt 1 casey
- both high level accuracy in both cool n hot go trials
- both made more errors on no-go tasks, low delayers made more errors on hot task
- low delayers made more errors with the happy no-go face
Why does blakemore link to science
Controlled laboratory experiments
Fulfil criteria of theory, control, evidence, replications
Why does blakemore link to biological
Falls within biological as it’s investigating effect of environment on developing brain in cats, demonstrated brain plasticity of kittens brains as neurones original primed to prefer one orientation switch to prefer the other
Why does Casey link to usefulness
- Studies linked high delayers at age 4 to development of better social-cognitive and emotional coping in adolescence
- if could create strategies to train brains of low delayers to become high delayers might help protect them from vulnerability to those problems above
