| Background | - Eriksson shown that human HIPPO has the ability to generate new cells throughout life (neurogenesis)
- Found rats in an ‘enriching’ environment leads to the enlarging of hippo |
| Hippocampus meaning | - HIPPO is linked to moving info from our short-term memory to our long-term memory
- Controls spatial awareness + navigation
- Can act as a cognitive map, neural representation of the environment |
| Voxel based morphometry meaning | - Neuroimaging analysis of brain anatomy
- Measures density of grey matter |
| Pixel counting meaning | - 2D measurement which counts pixels of the P+A, body of the HIPPO
- Measures grey matter volume |
| Blind Researcher meaning | - The pixel counter was blind to the VBM results whether the scans were of a taxi or non-taxi drive
- Avoids any bias that could occur from the readings of the brain scans and pixel |
| ‘The Knowledge’ meaning | – London taxi drivers are required to know the 25,000 streets within a six-mile radius of Charing Cross
- And general knowledge of major routes |
| MRI scan (magnetic resonance imaging) | – Standard brain scan |
| VBM (Voxel-based morphometry) | – A scan showing the density of the brain
- Measures volume of grey matter |
| Anterior hippocampus meaning | - Front |
| Posterior hippocampus meaning | - Back |
| 1 EXPERIMENT | 1 EXPERIMENT |
| Aim | - To investigate differences in the volume of the HIPPO in London taxi drivers + non-taxi drivers
- To see the neuroplasticity after extensive navigational experience |
| Research method | - Quasi Lab Experiment |
| Design (BOTH INVESTIGATIONS) | - Independent Measures
- Matched participants |
| Data collection (BOTH INVESTIGATIONS) | - Only Quantitative data of the brain scans and pixel counting and years of working |
| IV and DV | IV – London taxi driver or non-taxi driver
DV– Vol of HIPPO measured by VBM and pixel counting |
| What were the two samples? | - Group 1
- Control group |
| Group 1 | -16 taxi drivers, right-handed, male London taxi drivers, mean time as a licensed London taxi driver 14.3 years
- Healthy, all passed ‘The Knowledge’ |
| Control sample | - 16 right handed male non-taxi drivers, age matched, healthy
- Selected from the MRI scan database of 50 males which provided a comparison database of average hippocampi volume |
| Procedure | - Each individual had an MRI scan
- HIPPO were separated into different areas: R+L hemisphere, P + A
- Vol. of grey matter in A + P measured + compared
- MRI scans were analysed by VBM + Pixel counting which also gives a measure of volume (cross-sectional slices) |
| Control group | – Matched on age, gender, health, right handed
- Expert conducting the analysis did not know whether the MRI scan was of a taxi driver or not, this avoids bias |
| 2 CORRELATION | 2 CORRELATION |
| Aim | - To see if there is a significant correlation between the number of years spent being a taxi driver and the volume of the hippocamp
- To see if the brain can be altered by the environment |
| Research method | - Correlation |
| What were the two variables | - Variable 1= Length of time as a taxi driver
- Variable 2 = Volume of the right posterior hippocampus |
| Procedure | - Time in months as a taxi driver was correlated with the vol of the right posterior HIPPO taken from MRI scans of the taxi driver group |
| Controls | - Groups matched on age, gender, health, right handed
- Blind analysis meant that the expert conducting the analysis did not know whether the MRI scan was of a taxi driver or not |
| Results (EXPERIMENT) | - Taxi drivers compared to non-taxi drivers
- Taxi drivers had greater vol in the posterior HIPPO
- Non-taxi drivers had greater vol in the anterior HIPPO
- The overall size of the hippocampus body was similar |
| Results (CORRELATION) | - As length of time as a taxi driver increased, the vol of the right posterior hippocampus increased, + correlation
- As length of time as a taxi driver increased, the vol of the right anterior hippocampus decreased, - correlation |
| Conclusions | - Sig. fig. in the hippo of taxi drivers compared to non-taxi drivers
- Suggests that the environment can change structure of the brain
- + correlation found between time spent as a taxi driver + vol of right posterior hippo
- This disregards the explanation that people may choose to become a taxi driver because of a pre-existing brain difference |
| Sampling Bias | - 16 taxi drivers was quite large given they had to have an MRI scan
- All right handed males, cannot be generalized to females or left handers
- Age spread + time in the job contributed to a varied sample |
| cEcological validity | - Low EV, lab, very controlled, however the realism in this task didin't matter
- Interests/occupations not considered, so there could be individuals with other reasons to have high navigational skills
- However this isn’t likely to be an issue because the correlation demonstrated increased hippocampal volume with experience |
| Internal Validity | - High as it is impossible to alter the activity in their brains intentionally
- No risk of demand characteristics as they weren’t doing a task |
| Reliability | - Same individual assessed all of the brain scans
- Blind analysis, the conductor carrying out the analysis... |
| Usefulness | - Important for rehabilitating people with brain damage
- Although it only shows that the hipp can alter in adulthood, it could suggest that other areas of the brain could too
- Can lead to advances in diagnosis + treatment |
| Data | - Quantitative data is very good for statistical analysis and is measurements are highly objective |
| Research Method | - Lab, lots of scientific equipment + procedure
- Controlled + degree of control can be maintained in lab enviro. |
| Ethical considerations | - Fully aware of procedure + aims, gave consent
- MRI scans aren’t dangerous, other than some ppts may not like being in a small enclosed space for the scan |
| Ethnocentrism | - Not ethnocentric, investigating a species-specific behaviour
- But only representative of London taxi drivers so not everyone's hippo has a similar capacity for brain plasticity |
| Nature– nurture debate | - Shows how environmental demands placed upon the spatial memory of taxi drivers led to brain plasticity in their hippo
- As their experience increased so their hippo changed to accommodate the demands placed on their spatial memory |
| Psychology as a science | - Highly controlled - fulfils scientific criteria of theory, control, evidence and replication
- Objective method of measurement (MRI) - highly scientific |
| Link to the biological area | – Bio area explains behaviour through biological + neurological processes
- M hypothesised that experiences can cause changes in the brain
- He found that people who use navigation skills constantly in their work (taxi drivers) show differences in parts of their brains |
| Similarities between Maguire and Blakemore and Coopers | - Highly controlled lab
- Objective evidence, M with MRI scanner, B + C with neuropsychological measures
- Quantitative data
- Independent measures design |
| Differences between Maguire and Blakemore and Coopers | - M studied the human brain, B + C studied brains of cats
- M, snapshot study, B + C longitudinal study
- B + C studied visual neurons, M investigated hippocampus |
| How does the study of Maguire improve our understanding of brain plasticity? | - B+C only knew about how visual experiences in a kittens’ early life can modify their brains
- Showed that the environ can determine perception at both a behavioural and psychological level, this shows plasticity
- M tells us how the human brain works, tells us about how the grey matter in hippo can change depending if u r a taxi driver or not
- Showed how the brain adapts for memory and spatial awareness
- Both B + C + M tell us that brain plasticity occurs because of your surrounding environment |
| How does the contemporary study improve our understanding of individual, social and cultural diversity? INDIVIDUAL DIVERSITY | - Ms study showed that brain plasticity does not only apply to animals but to humans as well
- M showed that constant use of navigational skills led the brain to accommodate the demands placed on their spatial memory |
| How does the contemporary study improve our understanding of individual, social and cultural diversity? SOCIAL DIVERSITY | - Ms study doesn’t tell us more about social diversity
- But does show great improvements in the ability to measure human brain activity, allows for future research to now explore this |
| How does the contemporary study improve our understanding of individual, social and cultural diversity? CULTURAL DIVERSITY | - Ms study doesn’t tell us anything about cultural differences
- Only taxi drivers from one place were used
- However, the hippo is present throughout all cultures so it is reasonable to assume similar results could be found |
