Maguire Flashcards
Background Research
Lee shown that hippocampal volumes in birds/small mammals
enlarge during seasons where demand for spatial ability is greatest
Maguire wanted to see whether the human brain responds to experiences requiring spatial memory is the same way as birds/small mammals
Define
1) Brain plasticity
2) Spatial memory
3) Hippocampus
1) brains tendency to change and adapt as a result of experience and new learning
2) form of memory that allows us to navigate though an environment and remember locations
3) plays a role in memories and spatial memory
Aim of Maguire
To investigate whether there is a difference in hippocampal volume between taxi drivers and other people
Research method of Maguire
Quasi experiment
IV - whether the participant was a London taxi driver or not was naturally varying + not manipulated by researchers
DV - volume of hippocampi measured by analysing MRI scans using VBM and pixel counting
Experimental design of Maguire
Matched-participants design
= matched for health, handedness, sex, mean age and age range
Sample of Maguire
16 taxi drivers
all healthy, right-handed, male London taxi drivers with a mean age of 44 and mean time as licensed London taxi driver for 14.3yrs
Control group did not drive taxis (50 for VBM, 16 for pixel counting) matched for all characteristics
Why did Maguire use taxi drivers
London taxi drivers must have spatial and navigational infro (pass The Knowledge Test) on city of London to get taxi drivers licence
Maguire could then examine the direct effect of spatial experience of brain structure
Procedure of Maguire
used an MRI scanner to calculate the amount of grey matter in the brains of taxi drivers and set of control participants
VBM was used to calculate the volume of grey matter in specific regions of the brain to be measured precisely (3D measure 1.5x1.5x1.5mm)
Pixel counting was used to measure the volume of anterior + posterior hippocampi (2D measure)
> maguire counted no. of pixels in hippocampus then converted this into volume
The images were analysed by one person experienced in this technique and blinded to whether the scan belonged to taxi-driver or non-taxi driver
Difference between anterior and posterior hippocampus
Posterior = previously learned spatial information (memory of roads)
Anterior = more involved in learning of new spatial information
Results of Maguire
Posterior hippocampi volume of taxi drivers was significantly larger than control participants
Posterior hippocampi volume was positively correlated with amount of time spent taxi driving
Controls had significantly greater anterior hippocampal volume than taxi drivers
Conclusions of Maguire
There are structural differences between hippocampus of licensed London taxi drivers compared to those who aren’t
Taxi drivers navigational skills are associated with a distribution of grey matter in the hippocampus
Generalisability of Maguire
range of taxi drivers in terms of age and length of licence
> generalisable
only male and right-handed taxi drivers
> can’t generalise to females + left-handed taxi drivers
Reliability of Maguire
all participants had MRI scans + standardised techniques used to analyse scans
> VBM + pixel counting were standardised techniques to measure hippocampal volume
same experienced research counted pixels on all scans
> consistency in way hippocampal volume was measured > more replicable and reliable
Applications of Maguire
Rehabilitate people with brain damage
> suggests brain can change in response to enviroment
Validity of Maguire
NO EXPERIMENTER BIAS
= research analysing scan was blind to each participants condition (taxi vs non-taxi)
GOOD VALIDITY
= participants watched on age and right-handedness
= reduced participant variables affecting results
= can be sure its hippocampal volume is affected by taxi driver or not
Ethics of Maguire
INFORMED CONSENT
= MRI scans are powerful magnetic field so had to ask if taxi drivers had mental implants eg. pacemakers
= some people find MRI scanners claustrophobic
Type of data in Maguire
QUANTITATIVE DATA
= measurement of volume of hippocampus
Strength as it can be statistically analysed + objective
= the hippocampal volume of taxi-drivers could be easily compared against those of non-taxi drivers
Maguire and biological area
biological area looks at how biological factors affect our behaviour eg. genes, brain structure, neurons
Maguire looked at brains of taxi drivers + compared to non-taxi drivers using MRI scans
Found taxi drivers who pass Knowledge test have greater posterior hippocampal volume
Study shows how brain structure, a biological factor) can affect our behaviour eg. navigational skills
Maguire and key theme ‘brain plasticity’
found taxi drivers brain can change in relation to their job as they have to understand and learn routes around London
specifically, posterior hippocampal volume gets bigger
Maguire and Nature/Nurture Debate (interactionist view)
considers both nature + nurture
nurture
= brain adapts to out environment
= vol of grey matter in posterior hippocampus was greater in taxi drivers as it stores info about spatial memory
= vol of posterior hippocampus increases with length of time in job
nature
= certain brain structures eg. anterior + posterior hippocampi have particular functions determined by our biology
Two controls in Maguire
1) only use male right-handed participants for both taxi/non-taxi drivers to control participant variables
2) same researcher measured hippocampal volume using VBM
Evaluate usefulness of providing biological explanation for behaviour
Biological explanations are useful as they help us understand how biological factors eg, brain structures affect behaviour and lead to medical treatments
Maguire showed how hippocampus changed in taxi drivers vs non taxi drivers
useful as showed brain plasticity + can be used to rehabilitate people with brain damage
Not useful as biological explanations don’t consider how environmental factors affect behaviour
on other hand, Maguire did
to what extent does maguire change our understand of key theme
changes understanding of brain plasticity as it looked at humans whereas B&C looked at animals only
B&C looked at visual cortex of kittens changed as result to exposure of only H or V lines
Maguire looked at posterior hippocampal volume had increase in taxi drivers vs non. as result to navigational skills
To what extent does Maguire change understanding of individual, cultural and social diversity
INDIVIDUAL
= Maguire showed this in hippocampal volumes as taxi drivers with navigation skills cause grey matter in hippocampus to redistribute so there is more in posterior hippocampus
SOCAIL
= only used males so no
= showed improvements in measuring brain activity for future research
CULTURAL
= london taxi drivers
= could be cultural differences in brain plasticity
