Next time grumpy Aunt Gertrude growls at her bridge partner or one of her well-wishing nephews, look at it from this angle: She just may be smarter than all the rest.

New research suggests just that, revealing that older people with above-average intelligence tend to be disagreeable.

The study authors noted, however, that superior intelligence does not always go hand-in-hand with surliness -- with smart young people more likely to be open to new situations, rather than being disagreeable.

"It appears that at younger ages, openness to experience is the most important personality factor correlating with the attainment of facts, vocabulary, and book learning," said study co-author Jacqueline Bichsel, an associate professor of psychology at Morgan State University, in Baltimore.

"But when we get older -- and this hasn't been found before -- it appears that openness to experience is no longer as important, and what is important is a disagreeable nature," she added.

Bichsel and her colleagues reported their findings Thursday at the American Psychological Association's 2006 Convention in New Orleans.

The authors focused on 381 healthy adults between the ages of 19 and 89, who had various degrees of education ranging from completion of high school to graduate school.

The 246 adults who were over the age of 60 were classified as "older." That group was further divided into two equally sized smaller groups -- older adults with cognitive abilities comparable to that of the younger group, and older adults with cognitive abilities superior to all the rest, both young and old.

The remaining 135 adults below the age of 60 were classified as "young."

All the participants were given the same battery of tests and questionnaires to gauge both intelligence and personality traits such as openness, conscientiousness, extraversion, agreeableness, and neuroticism.

None of the adults was revealed to have any demonstrable age-related declines in their cognitive abilities.

In fact, the researchers found that while the younger adults performed no better than any of the older adults on any seven different measures of intelligence, the "superior" older adults actually outperformed all the rest on every cognitive test.

The researchers concluded that among the older participants, agreeableness appears to be negatively related to intelligence. This implies, the researchers suggested, that being older and unfriendly might actually equate with being smarter.

By way of explanation, the authors pointed out that prior research has indicated that highly intelligent people tend to be more independent, and that self-reliance can perhaps render the need to be agreeable less important.

The older "superior" group was also observed to be more conscientious, which was associated with better short-term memory and auditory processing -- two skills the study authors attributed to better test-taking abilities rather than improved smarts.

For young people, it was "openness" that appeared to be the key ingredient to gaining knowledge. Openness appeared to be specifically associated with better short-term memory. The researchers also found that young people who were relatively less extroverted also scored higher on knowledge tests.

The researchers concluded that the association between intelligence and personality changes with age -- with the kind of openness younger people need to absorb new information perhaps less meaningful to older and smarter adults who have already acquired a lot of knowledge.

"So, you don't necessarily need to get on cranky grandma and grandpa," said Bichsel, who was involved with the study while at Penn State University. "It may be good for them to be a little argumentative, and it may show that they are retaining a high cognitive capacity."

But, Richard Robins, a professor in the department of psychology at the University of California, Davis, expressed some doubt about the findings.

"I haven't heard of this kind of finding before, and this is a relatively small study sample," he said. "So, I wouldn't be surprised if the findings weren't replicated in a larger sample."

By way of explaining the complexity of the subject, Robins pointed to recent work he conducted with a sample of about 10,000 college-age students that revealed a weak but consistent association between young disagreeable men and women and slightly higher SAT scores.

This, he noted, is not in line with the current study's findings.

"So, I would be skeptical," Robins said, "about making any interpretations just yet, based on this age association."

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