Little evidence that old age causes work deterioration

By Beth Azar
Monitor staff

At 78, Supreme Court Justice John Paul Stevens is considered one of the more intellectual justices, known for his distinct reasoning skills in written opinions and his piercing questions during oral arguments.

This image of a sharp, highly productive member of what researchers label the 'old old'?as opposed to the 'young old' between 65 and 75?contradicts the more common perception that older folks become slow and confused, unable to compete in the working world. It also contradicts research showing that people?s cognitive abilities, such as memory, attention and reasoning?all of which are associated with job performance?deteriorate with age.

But, to date, a barrage of studies of many types of jobs support Stevens? ability to maintain his status on the court, finding little evidence for age-related declines in job performance.

'We want to know how this is possible,' says Georgia Tech psychologist Timothy Salthouse, PhD, who is one of several researchers looking for an answer. 'If cognitive ability is important to job performance and cognitive abilities decline with age?why is there no impact on job performance?'

Salthouse and others have proposed several hypotheses to explain the paradox. One is that older people compensate for a cognitive slowdown by using their accumulated experience and knowledge. For example, an older judge who has presided over hundreds of cases during a long career, may rely on memories of earlier judgments rather than reason through each case individually, the way younger judges do.

Another theory holds that job experience selectively protects the cognitive abilities specific to that job?architects maintain spatial skills while musicians maintain a strong short-term memory for melodies.

Neither of these hypotheses has been proved or disproved, say researchers. In fact, the answer appears to be much more complex than either theory suggests.

Offsetting deficits

Research on real-world job performance can be difficult, admit researchers. Measures of performance are tricky to design, and it?s difficult to gain access to a large number of workers because both employees and employers resist to intrusions by researchers.

As a result, many researchers have turned to the laboratory to tease apart the relationship between aging, cognitive abilities and job performance. Salthouse and his colleagues have been testing theories of how people may compensate for cognitive declines.

Highly experienced musicians, they find, still have declines in their ability to hold melodies in working memory, even though they use such skills when they play. Salthouse and graduate student Elizabeth Meinz, studied 128 people age 18 to 83 with musical experience ranging from zero to 60 years. People with more musical experience were better able to remember complex musical melodies than those with little or no experience, regardless of age. But that experience did not protect older musicians from age-related working-memory declines, the researchers report in the Journal of Gerontology: Psychological Sciences (Vol. 53B, No. 1, p. 60?69).

Researchers studying pilots find similar results: Although they see no general age-related performance declines, older pilots do show deficits in the cognitive skills, such as perceptual-motor and memory skills, that they use in their jobs.

The reason cognitive declines don?t seem to be related to performance declines may be because many jobs are more knowledge- and experience-based than cognitively-based, posits Salthouse.

In a study of crossword puzzle proficiency?largely considered a cognitive-reasoning task?he and graduate students Zach Hambrick and Elizabeth Meinzhis found that puzzling is primarily knowledge dependent. Even though older, experienced crossword puzzlers showed standard age-related declines in reasoning, they were at least as good, and often better, at completing puzzles as younger experienced puzzlers, the researchers find in a series of four studies in press in the Journal of Experimental Psychology: General. Their ability is due almost entirely to their greater knowledge base, and proficiency for younger puzzlers was also due almost entirely to knowledge, not reasoning.

'It could be that the reason we do so well as we age is that many tasks rely on knowledge, not fluid cognitive skills like reasoning,' says Salthouse.

Practice makes perfect?

Maintaining maximum skill may also depend in part on whether and how people practice. Experts become adept at a skill through 'deliberate practice'?practice aimed toward improving performance. Musicians who maintain a high level of deliberate practice show no declines in performance as they age, finds Florida State University (FSU) psychologist Anders Ericsson, PhD, and his colleagues. Declines only start when they retire and they practice less.

FSU?s Neil Charness, PhD, also has evidence that deliberate practice?more than amount of time spent playing?is the strongest predictor of success for professional chess players in Canada and Germany. And such practice is more important for older players to maintain their ranking than for younger players, says Charness.

Overall, success in timed chess tournaments declines with age. But if players aren?t forced to think quickly, they perform just as well as younger players, says psychologist Dean Keith Simonton, PhD, of the University of California, Davis.

Auditing aging

Older workers may always have a hard time competing with younger workers on tasks that require speed, agrees Czaja, director of the Miami Center on Human Factors and Aging Research, which is funded by the National Institute on Aging.

She and her colleague Joseph Sharit, PhD, have evidence that older people perform worse than younger people on three computer-based tasks that they?ve designed to simulate real-life jobs: A data-entry task modeled after a truck tracking form used by a large shipping company; a database-inquiry task modeled after health-insurance customer service jobs; and a problem-solving task using a computer program to balance bank accounts.

For each job, Czaja and Sharit trained and tested 120 people, ranging in age from 20 to 75. After a day of training, participants spent three hours a day for three days 'working' at the tasks.

The biggest predictor of performance on all the tasks was prior computer experience, says Czaja. But even after controlling for this, they found that older participants were significantly slower at the tasks than younger people. When they examined which cognitive skills might account for the age differences, they found that slower psychomotor speed explained all of the age-related difference on the data entry task. And poorer working memory and slower procedural speed accounted for differences in the account-balancing task.

'The age difference [in performance] is mediated by age differences in cognitive abilities,' says Czaja. She and Sharit will publish their results in the Journal of Experimental Psychology: Applied, the Journal of Gerontology and the International Journal of Cognitive Ergonomics.

Although these findings suggest some age-related performance declines, Czaja emphasizes the positive: The older people were perfectly able to learn the new tasks. And, although their productivity lagged behind their younger counterparts, they tended to be highly accurate in the work they completed.

'If companies are only concerned with amount produced, older adults will never compete with younger adults on tasks like these,' says Czaja. But if they?re concerned with accuracy and adequate productivity, older workers are perfectly capable.

Indeed, at least in creative jobs such as the arts and scientific research, the ratio of successful ideas to total tries stays relatively constant, Simonton finds.

'They?re shooting fewer times at the target, but their aim is just as good as it ever was,' he says.