And, once again, health/longevity research where the arrow of causality is very unclear. Does a stimulating mental environment stave off dementia, or is this a

And, once again, health/longevity research where the arrow of causality is very unclear. Does a stimulating mental environment stave off dementia, or is this a matter of the ability/desire to do something a measure of current capability? If you enjoy reading that effectively says it's something reasonably easy for you and thus is a measure of your mind.