The analysis found that among those followed, 551 people developed Alzheimer’s disease. For every one-unit increase in lifetime cognitive reserve, the risk of Alzheimer’s dropped significantly by 38%. Looking at different life stages, early, middle, and late-life cognitive enrichment were associated with risk reductions of 20%, 21%, and 29%, respectively.
That may not sound striking, so let’s put it in perspective. Compared to those in the lowest 10% of lifetime cognitive reserve, those in the top 10% had their average age of Alzheimer’s onset delayed from 88.4 to 93.8 years—a full 5.4 years later. For mild cognitive impairment (the precursor to dementia), this delay was as long as seven years. By life stage, early, middle, and late-life cognitive enrichment delayed dementia by 2.9, 3.5, and 5.5 years, respectively.
In other words, this is like investing in anti-aging for your brain. Reading more and building up cognitive reserves now could leave you with a mind as sharp in your eighties as someone else’s in their seventies. And it’s never too late to start—cognitive enrichment in later life had the greatest impact, delaying dementia by a full 5.5 years.
Further analysis revealed that higher lifetime cognitive reserve was associated with higher baseline overall cognitive function at the start of the study. More importantly, greater cognitive reserve also slowed the rate of subsequent cognitive decline. Specifically, compared to those with average cognitive reserve (the 50th percentile), individuals with low cognitive reserve (the 10th percentile) experienced a 14% faster rate of cognitive decline, while those with high cognitive reserve (the 90th percentile) saw their decline slow down by 10%. This protective effect was observed across all cognitive domains, including memory and processing speed.
To be honest, there is a huge body of research on this topic, especially with an explosion of papers in recent years. Going into all the details would be quite tedious, but they basically all point to the same thing: when older adults perform cognitive tasks, they often maintain their performance by additionally recruiting higher order brain regions. A subset of exceptional older adults, thanks to a lifetime of accumulated knowledge, skills, and highly efficient neural networks shaped by training, show a stronger ability to resist cognitive aging. Gosh, this suddenly brings so many things to mind. Maybe it’s time to take action.
I believe this may be more true than currently understood. It would be difficult to describe the phenomenon objectively, but when thinking about complex problems – as opposed to recalling solutions to similar ones – I am aware of myself drawing on cognitive processes and, importantly, specific intellectual tools of thought, that go back to years of my life on a graduate research team in which we were all pushing the limits of our intellect on a daily basis. That was more than 50 years ago and I can still “sense” the impact of those experiences on my thought processes.
It would be an interesting topic to explore further. As I write this, I am thinking about distinctions between the application of specific tools of thought (e.g., conceptual analysis, convergent and discriminant analysis), intellectual standards for conceptual and empirical adequacy and their many gradations, acquired habits for probing beyond the received view, and more. Each of these attributes (products, skills) is complex in its own right. It is a topic that I would like to see taken on by multidisciplinary research team that includes philosophers, and behavioral and brain scientists. Such a team might also benefit from the contributions of a health and nutrition specialists. I can clearly see the contribution of certain lifestyle elements to my mental functioning, or perhaps its duration across the day.