Quasi experiment -An experiment with a naturally occurring independent variable, research not/cannot manipulate.
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I.V?
Whether the participant was a taxi driver or not.
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D.V?
Volume of the hippocampi including -anterior, body and posterior regions.
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What was the D.V measured by?
VBM-3D measure of grey matter DENSITY in MRI scans + Pixel Count-2D measurement, count of pixels within x3 regions of the hippocampus; posterior, body + anterior to measure grey matter VOLUME
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Experimental Design?
Independent Measures- Participants were either in the taxi driver or control group. + Matched Participants- Control group + taxi drivers were matched on handedness, sex,mean age +age range.
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Sample?- taxi drivers
16 male licensed London taxi drivers+ Right-handed +Healthy medical
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Sample?-Control Group
50 male p's+ Non taxi drivers + Right-handed
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controls?
1)All p’s male 2)Taxi+non taxi drivers were age matched 3)All p’s from London area 4)All p’s right handed 5)All p’s scanned at the same unit
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Result- VBM?
1)showed no significant differences between the brains of the two groups except: Taxi drivers =increased grey matter volume in the right+left posterior hippocampi compared to controls.
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Results – Pixel Count?
1) Showed there was no significant difference in overall volume of the hippocampi between the x2 groups: 2) Taxi drivers=greater posterior hippocampal volume than controls.
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Results – Pixel Count?
3) Controls=greater anterior right hippocampal volume than the taxi drivers. 4)significantly greater hippocampal body volume on the right than the left in both the taxi drivers+Controls.
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Results - Correlation?- how?
Data correlated between time as taxi driver+volume of hippocampus.
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Results - Correlation?
1) Significant positive correlation between time as a taxi driver + volume of right posterior hippocampus. 2).Significant negative correlation found between time as a taxi driver+volume of anterior hippocampus
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Conclusions?
taxi drivers’ hippocampi may have changed due to studying for the ‘knowledge’ ,showing plasticity of the brain. + longer a cab driver, greater the volume of their right posterior hippocampus.
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Overall conclusion of Maguire?
The human brain has plasticity and can adapt to meet the needs of the enviornment.
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