Maguire (2000)

Preperation for SAQ neuroplasticity and methodology: brain imaging techniques

what is it?

study on london taxi drivers and brain plasticity

aim

investigate whether the hippocampus changes in response to extensive spatial navigation experience

sample

16 right-handed male london taxi drivers

control group

50 right-handed males (non-taxi drivers) from MRI database

taxi driver requirement

completed the knowledge test and had license for min. 1.5 years

control varibale

wide age range to control for age differences

research design

quasi-experiment (correlational, IV not manipulated)

single-blind study

researcher did not know which scans belonged to taxi drivers

MRI scans purpose

brain imaging to measure hippocampal volume

VBM

measured density of grey matter

pixel counting

measured hippocampal area from MRI images

posterior hippocampus findings

significantly larger in taxi drivers than controls

anterior hippocampus findings

significantly smaller in taxi drivers than controls

correlation

right posterior hippocampal volume positively correlated with years of taxi driving

conclusion

hippocampus can change in response to environmnetla demands

localisation of function posterior hippocampus

using previously learned spatial information

localisation of function anterior hippocampus

encoding new spatial layouts

strength: quasi-experiment

naturally occuring IV (years of taxi driving)

strength; blind analysis

reduced researcher bias

strength; ethics

safe, non-invase MRI, informed consent

limtiation: no causation

quasi-experiment cannot estbalish cause-effect

limtation: sampling bias

only right-handed male taxi drivers; generalisability limited

counter to ecological validitiy criticism

MRI measured anatomy only; not behaviour, so validity is not compromised