Maguire et al

Maguire et al

1. Aim:

   • Find out whether taxi drivers had diff brains to non-taxi drivers.
     • Maguire wanted to know if humans' posterior hippocampi gets bigger when migrating than when settled.

2. Hypothesis:

   • Taxi drivers would have structurally different hippocampus compared to non-taxi drivers.

3. Participants:

   • Experimental group: 16 male licensed black cab drivers aged 36-62 (average age 44) + average length of time as taxi driver 14.3 years, right-handed.
   • Control group: 50 Brain scans from MRI database of healthy, right handed males aged 32-62. None were cab drivers.
     • All had been licensed taxi drivers for at least 1.5 years

4. Variables:

   • IV: job (taxi/non-taxi driver)
   • DV: Scores on the MRI scans

5. Method:

   • Quasi-experiment. IV was naturally occurring.

6. Controls:

   • Taxi drivers + non-taxi drivers were age matched.
     • All participants were men.
       • All participants were scanned at the same unit.
         • Pixel counter was blind as to whether participant was taxi/non-taxi driver.

7. Analysing MRI scans:

   • 1st Technique: VBM
     • Automatic procedure w statistical mapping identifies differences in the density of grey matter in diff parts of brain.
       • Grey matter = dense neutral connections + associated w higher order thinking.
   • 2nd Technique: Pixel Counting technique
     • Calculating hippocampal volume: pixels counted on photographic 'slices' made through brain using MRI scan.
       • Person counting pixels was blind to whether participant was taxi/non-taxi driver.
         • Pixels counted for anterior, posterior + body of hippocampus.

8. Volume:

   • Taxi drivers have greater grey matter volume in their posterior right hippocampus.
     • Controls have greater volume in their anterior hippocampus.

9. Procedure:

   • Structural MRI: can involves using computer software programme to reduce 3D image of brain.
     • MRI: works using radio waves to obtain 3D images of brain + body tissue
       • Scans analysed using VBM + PCM. Resulting in not being able to calculate volume of grey matter in hippocampus.