Navigation-related structural change in the hippocampi of taxi drivers.
Level 4 - case-series / case-control
Cross-sectional case-control neuroimaging study comparing taxi drivers to controls.
PubMed 10716738 · doi:10.1073/pnas.070039597
What was done
Structural magnetic resonance imaging (MRI) scans were collected and compared between licensed London taxi drivers, who have extensive spatial navigation experience, and control subjects who did not drive taxis. Regional hippocampal volumes were analyzed, and relationships between volume and duration of taxi driving experience were assessed.
What was found
The posterior hippocampi were significantly larger in taxi drivers compared to controls, whereas the anterior hippocampus was larger in control subjects than in taxi drivers. Posterior hippocampal volume correlated positively with the amount of time spent working as a taxi driver, while anterior hippocampal volume correlated negatively with time spent driving. The abstract reports no exact numerical values, p-values, or sample sizes.
Why it matters
This study provides landmark evidence supporting structural neuroplasticity in the healthy adult human brain, showing that specialized, intensive cognitive demands such as spatial navigation are associated with regional anatomical alterations in the hippocampus.
Limits
The abstract does not disclose the sample size, participant demographics (such as age or sex), or quantitative effect sizes and confidence intervals. Because of the cross-sectional, observational design, causality cannot be definitively established from these data alone, leaving open the possibility of pre-existing anatomical traits influencing career selection despite the reported correlation with driving experience.
Cited by
- supports London taxi drivers who memorize city street layouts have greater gray matter volume in their hippocampus compared to controls.
- supports London taxi drivers have physically larger hippocampus regions due to spatial learning required for 'The Knowledge'.