Component 2: Maguire et al (Biological) Flashcards
What is Maguire et al.s study about?
Taxi-driver brains
What is the background to Maguire’s study?
The hippocampus is a small part of the brain. There is one hippocampus in each hemisphere and is found in the temporal lobe.
The researcher has shown that the hippocampus is central to spatial memory. For example. in species that have a need for a spatial memory the hippocampi are larger than in species with less need for spatial memory.
In some animals the size of the hippocampi increases during seasons when they use their spatial memory the most.
What was the aim of Maguire’s study?
To investigate the volume of grey matter in the hippocampi of the taxi drivers who rely on spatial navigation.
What was the research method of Maguire et al.s study?
Quasi experiment (IV- whether the participant was a London taxi driver or a person who didn’t drive a taxi. DV- was the volume of hippocampi including their anterior, body and posterior regions, measured by analysing MRI scans of participants brains using the two techniques of VMB - identifies differences in grey matter that enable 3D representation & pixel counting
The study also used matched pairs design.
Describe the sample in Maguire et al.s study.
It was a self-select sample.
The experimental group of 16 taxi drivers were all healthy, right handed, male, London taxi drivers, with a mean age of 44 years old.
The control group who did not drive taxis (50 for VBM analysis and 16 for pixel counting) were matched for health, handedness, sex, mean age and age range.
Describe the procedure of Maguire et al.s study.
- The scans of the control group were selected from the structural MRI scan data base at the same (i.) VBM (Voxel Based Morphometry) which is an automatic procedure that ‘normalises’ the scans to a template to eliminate overall brain size as a variable and then identifies differences in grey matter density in different regions of the brain. The brains of the 16 taxi drivers were compared to those of the non-taxi-drivers to see if there were any differences in structure.
(ii.) Pixel Counting compared the volumes of anterior, body and posterior cross-sections of the taxi drivers hippocampi with those of a previously age, gender and handedness matched sample of 16 controls taken from the 50 used in the VBM analysis. The images were analysed by one person experienced in the technique and blinded to whether the scan was of a taxi driver or a control and the VBM findings. This procedure allowed the total hippocampal volume to be calculated.
What were the results of Maguire et als study?
Taxi drivers had significantly increased grey matter volume in the right and left posterior hippocampi compared to controls.
In the controls there was a relatively greater grey matter volume in the right and left anterior hippocampi compared to the taxi drivers.
Correlations showed a significant positive correlation between the length of time as a taxi driver and the right posterior hippocampal volume, but a negative correlation for the anterior hippocampal volume.
What were the conclusions of Maguire et als study?
It can be suggested that the changes in the arrangement of hippocampal grey matter are acquired i.e.. due to nurture.
Findings also show the possibility of local plasticity in the structure of a normal human brain which allows it to be adopt in response to prolongued environmental stimuli.
