Senior moments

Psychologists divide general intelligence into two categories: crystallized and fluid. Crystallized intelligence consists of the knowledge and skills that accumulate over a lifetime, such as vocabulary, storehouse of facts, and how to do things, such as knitting and skiing. Fluid intelligence consists of our ability to reason, flexibly engage with the world, recognize patterns and solve problems. An emergency room doctor uses fluid intelligence to assess symptoms and make a diagnosis; she uses crystallized intelligence to treat the problem.

Crystallized intelligence accrues over a lifetime and may peak at about age 65 or above. Fluid intelligence tends to peak at about age 20, then decline with age. The rate of decline varies from person to person. Some people, such as ninety-three-year-old Warren Buffet, have managed to retain strong fluid intelligence. Morrie Markoff, who died at the age of 110, remained mentally sharp to the end. (His eighty-two-year-old daughter is donating his brain to science.) But these guys are outliers.

So what about that euphemism “senior moments? We old people—I turn 88 this month—say we’re having a “senior moment” when we can’t remember something. It seems less embarrassing than saying “I can’t remember.” I have lots of those moments. They consist mostly of an inability to remember a name, word, or phrase. Supposedly such moments are normal “age-related memory loss,” probably from decreasing neurotransmitters and brain size. I haven’t been able to find out where that fits in with the crystallized/fluid scheme. Maybe it doesn’t matter.

For an introduction to this blog, see I Just Say No; for a list of blog topics, click the Topics tab.