Core Study – Maguire et Al
– Mean age 44 (range 32-62 years)
– All participants licensed London taxi drivers for more than one and a half years and had completed the knowledge course
– Control group of 16 non-taxi drivers, matched on age range of taxi drivers
Weakness – Only observes structure, doesn’t tell active function of the brain
Pixel Counting – Measures volume of hippocampus. it provides a two-dimensional measurement of an area.
-increase in grey matter in the left and right hippocampus. The increase was limited to the POSTERIOR.
-They had a greater volume in the anterior
-No difference in the overall volume of their hippocampus compared to the control group – but ti 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.
– 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.
– 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
– Test the participants over a certain period of time ensuring that the test is an exact replication of the first assessment
– Participants could then be tested a week later using the same process
– This length of time should not allow natural changes in the brain to occur, therefore making it similar to those before
– The data produced would most likely be the same – MRI scans are very reliable as they are an independent, objective measurement
– By using a machine to gather data, researchers are able to:
-Rule out Human Error
-Rule out Investigator Bias
– Increase reliability
– Data produced from an MRI scan is quantitative, which makes it easier to analyse and to repeat the test.
Also, include other types of drivers e.g. comparing emergency drivers with public transport drivers and having an equal number of both for each group. This would make the study more generalised to a wider population as it will be more representative of drivers.
Also, quantitative data was collected through precise measuring equipment, increasing validity and this also eliminates demand characteristics.
Weaknesses – Differences between the groups may have been due to other factors