Wednesday, October 13, 2010

Cognitive ability: use it or lose it?

A study just published in the Journal of Economic Perspectives tells us that if we want to retain our cognitive ability into old age we shouldn't retire.  The old 'use it or lose it' axiom.  But, as Gina Kolata points out in the NYT write up about the study, it could just be that people who are losing their cognitive skills retire earlier than those who aren't.  Does this study sort this out?

The authors analyzed the results of memory tests given to 22,000 Americans over age 50, administered by the National Institute on Aging every 2 years.  The test is a measure of how well people remember a list of 10 nouns immediately after hearing them, and then 5 or so minutes later, after having been asked other survey questions.  A perfect score would be 20.  Studies have been done in a number of countries in Europe and Asia, so that cross-cultural comparisons can be made.

As Kolata wrote,
People in the United States did best, with an average score of 11. Those in Denmark and England were close behind, with scores just above 10. In Italy, the average score was around 7, in France it was 8, and in Spain it was a little more than 6.
Examining the data from the various countries, Dr. Willis and his colleague Susann Rohwedder, associate director of the RAND Center for the Study of Aging in Santa Monica, Calif., noticed that there are large differences in the ages at which people retire.
In the United States, England and Denmark, where people retire later, 65 to 70 percent of men were still working when they were in their early 60s. In France and Italy, the figure is 10 to 20 percent, and in Spain it is 38 percent.
So, if it's true that retirement leads to cognitive decline, what is it about retirement that would do this?  It's hard to think of a single factor that all employment shares, other than a paycheck -- not everyone has a schedule, or punches a clock, or irons a shirt in the morning, or has to be at an office at 9, or socializes at the water cooler, or leaves their work behind when they go home at 5.  We can't even say that everyone must be competent at their job (see our post on the Ig Nobel prize winning paper about this very subject.)  And certainly not everyone is happy at work.  Similarly, not all retirements are equal.  So what's the common denominator?

The authors propose two possible answers.  One is the "unengaged lifestyle hypothesis", or mental retirement which accompanies actual retirement.  The other is that with the prospect of retirement, the soon-to-be-retiree slows down mentally in preparation, and stops "investing in human capital".  The "on the job" retirement effect.

Well, neither of these are very compelling explanations to us for a number of reasons including that a lot of people are busier in retirement than when they were employed, and we all know employed people who checked out long before they even gave retirement a thought.

Indeed, a number of further questions remain unanswered, in addition to Kolata's question of which came first, retirement or decline.  What would the slope of the line look like in 10 year olds cross culturally, for example?  Or  40 year olds?  That is, is the difference in ability (and, by the way, the top score, 11 words remembered correctly out of 20, doesn't strike us as all that good!) only apparent in older people?  Does the ability to remember 10 words actually indicate cognitive abilities such as reasoning or logic?

And, of course, there's the Bear Bryant phenomenon that we have to think about here at Penn State. Bear Bryant was the legendary coach of the University of Alabama football team.  At the tender age of 69, perhaps knowing that his best years were behind him, he decided to retire.  When a reporter asked him what he would do in retirement, he joked that in a week he'd be dead.  Four weeks later, he was!

Now this is relevant because our coach here at Penn State, the even more legendary Joe Paterno, is about to turn 84, with 2 years remaining on his contract.  That may be more games than his team will win the rest of the year, but the point here is that there have been quips that he doesn't want to end up like Bear Bryant.  So if he never retires.....he'll be immortal!
So the premonition spook could be a factor in peoples' retirement decisions, when, or perhaps if, they have a choice.

But before we decide to work til we drop, or work so we won't, we need to see the results of a more rigorous study.

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