The Tireless Brain

There was no doubt about the executives' IQs. They were all successful men who had demonstrated their ability to get ahead in highly competitive fields. But now their average age was 52, and many were older. Were they slipping? If so, how badly? In some cases, their employers wanted to know. In others, the men themselves wanted the answer. In all cases, Psychologists Willard A. Kerr of the Illinois Institute of Technology and Ward C. Halstead of the University of Chicago wanted to find out whether a man's mental ability necessarily declines with age.

Each executive took some tests that seemed, at first glance, to have nothing to do with mental ability. They were asked to show how steady they could hold their hands, how fast they could wiggle their index fingers, how fast a light could flicker before they saw it as a steady beam. Such studies were to show how well the nervous system was functioning at the physiological level. There were other tests that dealt with reactions to abstract patterns, and that graded the subjects on ability to understand and remember what they heard and read. Because of little-understood crossovers in the brain's circuitry, results of all the tests gave clues to each man's ability to absorb new ideas and deal with new words.

The tests were also designed to show actual mental impairment, which could be the result of arteriosclerosis or other damage to brain arteries. But among executives subject to regular medical checkups, such impairment was not likely to have gone undetected. What the psychologists were really looking for was any suggestion of changes in mental function resulting solely from age. Among the men in their 50s, they found no changes that were inevitable. Some of the men in their 60s and 70s showed a loss of memory, reasoning and decision-making power, but many did not. Most of the group of 424 aging executives showed as much mental agility as a bunch of medical students averaging 25 years old.

Any decline of mental powers with age, the psychologists conclude, is more likely to result from the brain's getting too little rather than too much work. The brain simply does not get exhausted from overwork, though the individual may get worn out from emotional strain associated with his effort.

"Mental fatigue independent of emotional strain probably never has been measured," says Dr. Kerr. "It takes less energy to think the greatest thought ever thought than it takes to spit."

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