Acquiring "the Knowledge" of London's layout drives structural brain changes.
Level 3 - non-randomized controlled study
Prospective longitudinal controlled cohort study tracking structural brain changes over time
PubMed 22169537 · doi:10.1016/j.cub.2011.11.018
What was done
A prospective longitudinal study tracked average-IQ adults over four years as they trained in the complex layout of London's streets ("the Knowledge") to become licensed taxi drivers. Structural brain imaging (measuring gray matter volume) and memory assessments were performed before and after the training period across three groups: trainees who successfully qualified, trainees who failed to qualify, and non-trainee control participants.
What was found
The abstract reports no numerical values, effect sizes, or group counts. It qualitatively reports that trainees who qualified developed a selective increase in gray matter volume in the posterior hippocampus alongside changes in their memory profile. In contrast, trainees who failed to qualify and control participants showed no structural brain changes.
Why it matters
This study provides longitudinal evidence that long-term, intensive cognitive training in real-world spatial navigation can induce selective macrostructural neuroplasticity in the adult human hippocampus.
Limits
The abstract does not provide exact sample sizes, attrition rates, or quantitative effect sizes for brain volumes and memory tests. Group allocation was non-randomized, meaning self-selection and baseline differences between those who succeeded and those who failed training could confound the observed structural changes.
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'.