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Maguire et al (2000)
your amazing brain!
Greek name
hippocampus
A London Taxi
A sea horse
What do these have to do with your brain!
Maguire et al (2000)
your amazing brain!
Navigation related structural change in
the Hippocampi of London taxi drivers
Interesting Question:
Does the structure of your brain change
in response to environmental demand
Maguire et al (2000)
your amazing brain!
Where in the brain is the hippocampus
What does the
hippocampus do?
The role of the
hippocampus is to
facilitate spatial
memory (navigation)
Maguire et al (2000)
your amazing brain!
Where in the brain is the hippocampus
Why hippocampi?
Each hemisphere of
the brain has a
hippocampus
hippocampi means two
Maguire et al (2000)
your amazing brain!
Research Question
Can changes in the brain be detected in those with extensive navigation
experience ?
The hypothesis
That the hippocampi in London taxi drivers will be structurally different to
the hippocampi in non-taxi drivers
Maguire et al (2000)
your amazing brain
•London
taxi Drivers ‘On the knowledge’
•It takes two years to train to become a London Taxi driver
•Must memorise thousands of routes
•Tested by police before a license issued
Maguire et al (2000)
Method: Quasi experiment
2 groups of participants (their brain)
 IV
London Taxi driver brain
Non taxi driver brain
 DV
structure & volume of
hippocampi
Comparison of analysis of MRI scans
Maguire et al (2000)
Participants
 16 right handed, male, taxi drivers
 Average age 44, all licensed more than 18
months, average time as taxi driver 14.3
years
 16 right handed, male, age matched, non
taxi drivers
Maguire et al (2000)
How was it done?
The procedure
 MRI scans of brains of 50 healthy, right
handed, male, non taxi drivers aged 33 61 were analysed to establish a
comparison data base of ‘average
hippocampi’
 Analysis by Voxel Based Morphometry
(VBM)
Maguire et al (2000)
The procedure
 MRI scans of brains of 16 taxi drivers and
of 16 matched controls were analysed by
VBM and compared to the data base of
images
 Control: the expert conducting the
analysis did not know whether MRI scan
was taxi driver brain or not
Maguire et al (2000)
Findings (1)

increased volume of grey matter in both
the right & left posterior hippocampi in
taxi driver brains
Maguire et al (2000)
LH
left hemisphere
RH
Right hemisphere
Maguire et al (2000)
Findings (2): Correlational analysis
 Variable 1: length of time as taxi driver
 Variable 2: Right posterior hippocampus
 volume of right posterior hippocampus
increased as length of time as taxi driver
increased
Maguire et al (2000)
Findings (2): Correlational analysis
Maguire et al (2000)
Findings (3)
 taxi drivers had greater volume in the
posterior hippocampus but non taxi
drivers had greater volume in the anterior
hippocampus
 indicating redistribution of grey matter
in hippocampus
Maguire et al (2000)
Conclusion
 That the structure of the brain changes in
response to environmental demand
Conclusion
 That the mental map of the city of
London is stored in the posteria
hippocampi
Maguire et al (2000)
Is this useful?
The evidence that normal activity can
induce changes in the structure of the
brain, and in the volume of grey matter,
has many implications for rehabilitation
after brain injury
Maguire et al (2000)
Ecological Validity?
Is the way the experiment
◦ measures the DV (brain structure)
◦ and the experimental setting
◦ and the sample of participants
realistic in a real life setting?
Discuss: why or why not?
Maguire et al (2000)
Types of data
Discuss: strengths & limitations
Quantitative: matters of fact objective, scientific
& replicable, useful for analysis & comparison
Qualitative: matters of opinion, subjective, rich in
detail, can be hard to analyse, may be
misinterpreted
Maguire et al (2000)
The experimental methodology
Was the method appropriate for the aim?

Are the experimental conditions realistic?
(mundane realism = real world realism)

How was the DV operationalised and was this a
valid measure of the behaviour being studied?
Maguire et al (2000)
The experimental procedure
How were the participants allocated to the
conditions and were controls used to remove
‘extra variables’ ?
 Were there any cues that might have
generated demand characteristics ?
 Reliability: Could the study be replicated to
find the same results? Why or why not?

Maguire et al (2000)
The sample
◦ Who were the participants
◦ Was the sample biased in any way?
◦ Was the sample large enough to mask the effect
of individual differences?
◦ To which population can we safely generalise the
findings?
Maguire et al (2000)
Psychology!!!
Brains,
taxis,
sea horses
The most
interesting
science