maguire et al. Flashcards
background
according to maguire, the role of the hippocampus is to facilitate spatial memory, in the form of navigation, from previous studies it was impossible to know whether differences in brain anatomy are predetermined, or whether the brain is susceptible to plastic changes, in response to environmental stimulation – in this case driving a taxi
aim
To examine whether structural changes (plasticity) could be detected in the brain of people with extensive experience of spatial navigation (London taxi drivers) and to investigate the functions of the hippocampus in spatial memory
research method
quasi experiment in a lab setting
what is a quasi experiment
IV not manipulated- contains a naturally occurring IV (difference between people that already exists eg. gender,age)
- researchers only have partial control of their independent variables- so you cannot be certain that the IV affects the DV
sample
- 16 right handed male taxi drivers
- mean age: 44
- all participants had been driving for more than 1.5 years and had completed the knowledge course
- control group of 16 non taxi drivers matched on age range of taxi drivers
procedure
- used MRI scans (by measuring soft tissue by exposing the brain to a strong magnetic field and radio waves to produce detailed pictures of the brain)
hypothesis
If there were any differences in the brains of those who rely heavily on spatial navigational skills in their working life, then these differences would be found in their hippocampus.
limitation of the sample
- does not include women or left-handed people. - - This is a limitation as there are likely to be female London taxi drivers, and it may be that female navigational ability may be different from males due to stereotype views about female drivers.
- This means that any conclusions drawn will not be representative of all London taxi drivers and so the study cannot be generalised of the whole population.
What methods did the researchers use to analyse the images produced from the MRI scans?
- VBM
- pixel counting
what is VBM
Measures density of grey matter in the brain. It provides a three-dimensional measurement of the volume of an area.
what is pixel counting
Measures volume of hippocampus. it provides a two-dimensional measurement of an area.
results from VBM
Taxi Drivers- increase in grey matter in the left and right hippocampus. The increase was limited to the POSTERIOR.
Control Group
- They had a greater volume in the anterior
results from pixel counting
Taxi Drivers - No difference in the overall volume of their hippocampus compared to the control group - but it was different when comparing specific regions.
Both methods showed higher volume of grey matter in the POSTERIOR for TAXI DRIVERS, and higher volume of grey matter in the RIGHT ANTERIOR for NON-TAXI DRIVERS.
what did the results show?
(correlation)
- A negative correlation between the length of time as a taxi driver and the volume of grey matter in the right anterior - the longer the time spent as a taxi driver the less the volume of grey matter in the right anterior.
- A positive correlation between the length of time as a taxi driver and the volume of grey matter in the right posterior - the longer the time spent as a taxi driver the greater the volume grey matter in the right posterior.
conclusions
The brain has plasticity - the ability to change to meet the demands of the environment. This is why there was a greater volume associated with the taxi drivers with the greater time spent as a taxi driver.
- The left and right sides of the hippocampus have different functions - the right side may be responsible for mental maps - this may be why the taxi drivers with more experience had a greater volume.
- Anterior Hippocampus - involved in previously learned information
- Posterior Hippocampus - involved in new environmental information
