The Neurology of Grumpiness

There is a thin line between honestly speaking one’s mind and lacking all social graces, and that line seems to blur with age. Old people say things that the rest of us would never consider saying publicly. Things that make us cringe when we hear them, like racially insulting remarks. Is it simply that times have changed, and old people are from a different—and far less tolerant--era? Or perhaps those in their twilight years just don’t care anymore whether they insult people.

Each of those explanations may contain an element of truth, but the root cause of such rudeness may be even more fundamental than that. Indeed, new studies suggest that something as basic as age-related changes in the brain tissue may be underlying the crankiness of old age as well as other socially inappropriate behaviors.

Psychologist William von Hippel of the University of Queensland, Australia, suspected that old people’s insulting remarks aren’t really meant to be insulting, that they related more to a lack of censorship than to meanness of spirit. He knew that the brain—especially the tissue of the frontal lobes—tends to atrophy with age, and that such atrophy could theoretically impair what’s called “executive functioning.” Executive functioning includes such skills as future planning and self-control over thoughts and behavior. He decided to explore a possible link between the loss of frontal lobe neurons, loss of inhibition, and unacceptable behavior.

He used several psychological tests to measure volunteers’ ability to censor themselves. The “trail making test,” for example, presents volunteers with randomly arrayed letters and numbers, and they are required to draw a line from A to 1 to B to 2, and so forth. It’s hard, because to do it right one must override the basic urge to both count and recite the alphabet. Or, in the so-called Stroop test, people see the word red in green letters, and they must quickly say the color of the ink; this requires that they quash the automatic impulse to read. Both of these tests, and others like them, provide a good measure of one’s ability to control and inhibit one’s thoughts.

Old people tend to have diminished capacity for thought control on such lab tests, probably a result frontal lobe degeneration. But here’s the interesting finding, as reported in the October issue of Current Directions in Psychological Science: When von Hippel compared the test results with actual social behavior in the elderly, he found that the only old people who made inappropriate social remarks were those with diminished cognitive capacity. And these people knew their remarks were wrong. They professed egalitarian beliefs, and did not want to be perceived as prejudiced, but they appeared unable to keep themselves from blurting out their unwelcome thoughts.

Racially insensitive remarks are just one example of social blunders in the elderly. Old people are also more likely to ask awkward questions in public settings, like: “Have you gained weight recently?” Or they just talk excessively about things that are not relevant to what everyone else is talking about—“off-target verbosity” in the jargon. Von Hippel found that these uninhibited behaviors are also linked to poor executive functioning resulting from brain atrophy.

One of von Hippel’s most intriguing and disturbing findings has nothing to do with insults or rudeness. He found that loss of self-censoring power is also connected to a particular kind of depression that strikes late in life. Presumably the normal brain degeneration of aging leads to an inability to censor one’s thoughts as well, leading to rumination, which in turn leads to mood disorders. Grumpy old people, it appears, may be saving the worst of their grumpiness for themselves.

For more insights into the quirks of human behavior, visit “We’re Only Human . . .” at www.psychologicalscience.org/onlyhuman.