The elderly man had just sat down in the pew. Folding up his walker, he watched his home health-care aide push his wife’s wheelchair down the hallway toward the ladies room, then turned to me (I was serving as an usher at this service). "Will you tell the colored girl where I’m sitting?”

I cringed. But, figuring there was no point in saying anything, I just nodded politely and put the man’s language down to his age, to being raised in an era when “colored” was acceptable. At least he didn’t say something worse.

Studies since the late 1990s have shown that older Americans tend to be more racist than younger people. That has been explained by the Social Security generation growing up, and having its social and political attitudes formed, in a period when racism and ethnic prejudice were not as unacceptable as they became in, say, the 1960s. But now there is evidence that this generational explanation is only part of the story, finds a study being published in the October issue of the journal Current Directions in Psychological Science.

Many people harbor unintentional and even unconscious stereotypic thoughts--"ethnic or racial group X is [fill in the blank with unflattering adjective of your choice]"--which we manage to overcome or at least squelch. By “we,” I mean our frontal cortex, the site in the brain that acts to inhibit unwanted thoughts and behaviors. (It is immaturity of the frontal lobes that makes many teens so impulsive and unable to inhibit their worst instincts.) “It might be that older adults have greater difficulty inhibiting these stereotypic thoughts despite their efforts to avoid being prejudiced,” writes psychologist William von Hippel of Australia’s University of Queensland. Older adults might be "more prejudiced than younger adults because they can no longer inhibit their unintentionally activated stereotypes.”

The loss of inhibition is the result of the brain’s traitorous tendency to shrink as we age. The frontal lobes in particular atrophy. The result is educed ability to inhibit irrelevant or unwanted thoughts. This loss of inhibition might explain other behaviors that crop up in many elderly, including “social inappropriateness.”