Do all human beings lose some brain capacity with age?
A | Most certainly. We all lose about 85,000 neurons a day. We can just kiss them good-bye. Q | At what age does this decline in brain cells start? A | We’re probably at our mental peak at 18 or 19 years old, at least for most of the cognitive performances that can be measured in the lab. Q | What a waste of adulthood! A | Well, in caveman days, humans didn’t live much past 23 or 24. We lived just long enough to be reproductively competent and to raise kids who could also reproduce. Which is why after age 40, we’re in genetic free fall in terms of aging. Sorry about that. Q | How does the loss of neurons affect our ability to learn and to remember new information? A | The effects still aren’t well-documented. But the answer to your question really depends on how we define memory. When a piece of information comes into your head, it goes through four separate processing steps, all of which you could call learning of a sort. The first step is encoding, in which information actually enter
