Greek name hippocampus Maguire et al (2000) your amazing brain! 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! Why HIPPOCAMPI? Each hemisphere of the brain has a hippocampus hippocampi means TWO Where in the brain is the hippocampus
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: Natural 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 hippocampi in taxi driver brains
LH left hemisphere RH Right hemisphere Maguire et al (2000)
Maguire et al (2000) • Findings (2): Correlational analysis • Variable 1: length of time as taxi driver • Variable 2: Right posteria hippocampus • volume of right posteria 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 posteria 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 datadiscuss: strengths & limitations • Quantitative = matters of fact objective, scientific & replicable • useful for analysis & comparison • or: • 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