Does Lifelong Learning actually make a difference, or is it overhyped?

The evidence linking continued mental engagement to dementia risk is unusually self-aware about its own biggest weakness -- reverse causation, where early undetected cognitive decline reduces a person's activity levels rather than inactivity causing decline -- and several recent studies were designed specifically to address it. Weighing the data: Lifelong Learning looks potentially significant but still under-researched — its estimated impact on longevity is rated high (55/100), while the evidence itself is only moderate (62/100).