Context/background
Biological workings of brains determine how individuals behave
Maguire said that experiences can cause changes in brains and found people who use navigation constantly = differences in the hippocampus
The hippocampus= a small curved part of the brain in the limbic system involved with memory, learning and emotions, there is 1 hippocampi above each ear
Mammals and birds = larger hippocampuses because of spatial memory, food storing, but there was not much human research into this before maguire.
Aim
To investigate if there is a difference in hippocampus volume between individuals with navigational experience or not
Method
Magnetic resonance imaging (Mri) scanning, a magnetic field affects water molecules and produce a detailed image that shows the brain in 3 shades and produce a detailed image
Voxel-based morphometry = VBM = images in blocks = voxels
pixel counting = image analysis technique, allows number of pixels in an area occupied by a tissue type are counted and converted into a volume
quasi-experiment because IV (taxi driver or not) was natural
DV= volume of hippocampus
Independent measures, matched participants
Procedure
16 taxi drivers, right handed, on average 44, and on average had 14.3 years experience as a licensed london taxi driver
Control group= 50 for VBM analysis and 16 for pixel counting = matched p's
The control group was used to compare the hippocampus responses to the taxi driver brains
Findings
VBM= no significant difference except
a. taxi drivers had less grey matter in their hippocampus
b. controls = more grey matter in the anterior hippocampus (front)
Pixel counting= taxi drivers had greater posterior hippocampus volume than the controls and the control had greater anterior volume
Correlations= positive correlation between time as a taxi driver and right posterior hippocampus volume
Conclusions
Structural differences between hippocampus of taxi drivers and non taxi drivers
Time as a taxi driver = greater hippocampul volume
Supports nature > nurture
Supports brain maliability and plasticity
Evaluation
Research method- lab experiment so high control and higher validity, cause and effect was fairly clear, and it was straightforward to replicate, had high consistency
No demand characteristics as they did not perform a task
Data type- quant. data = easy to compare and analyse, also highly objective so independent of experimenter bias
Ethics- informed consent, could be dangerous because of the magnet in the scan
Sample- large sample but all work in london so ethnocentric, right handedness may affect results, was a varied sample when it came to age