How Joe Biden Could Address the Age Issue | The New Yorker
Our minds naturally evolve over the course of our lives. In general, fluid intelligence—our ability to think creatively, reason abstractly, and learn new skills—declines with age, whereas crystallized intelligence, by which we integrate accumulated knowledge to solve problems and make decisions, tends to increase. The speed at which we process new information peaks in our twenties and thirties; our vocabularies expand into late middle age. Memory loss exists on a spectrum, and even speaking of “memory” as a monolith is misleading. (Deficits in working memory versus long-term memory, for instance, suggest different pathologies.) Geriatricians often try to differentiate normal age-related memory loss from what’s known as mild cognitive impairment. Whereas the former leads to minor and occasional lapses—where’s my phone? when’s his birthday?—the latter indicates a more significant limitation, and, in a third of cases, progresses to Alzheimer’s disease within five years. These determinations are rendered through a battery of neuropsychiatric tests and a series of careful conversations with patients and their families—not on cable news or by special counsels.