Oct. 12, 2010 -- You might be counting down the years until retirement, but new research suggests that hanging up your hat could be bad for your head. A new study of data from countries around the world found that early retirement can lead to poor memory.
Watch "World News with Diane Sawyer" for more on this story tonight on ABC.
Researchers from the RAND Center for the Study of Aging and the University of Michigan examined 20 years' worth of government data from the United States and a dozen European countries, plotting the performance of 60- to 64-year-old men and women on memory tests, along with the percentage of the population still working.
Americans, who often work well into their 60s, performed better on the memory tests, while Spanish, Italian and French men and women, most of whom retire by their early 60s, performed the worst. Other countries' cognitive performance also fell on the trend line, implying that the workplace is far better mental stimulation than any brain teaser.
"The big difference here is that people spend thousands of hours at work, and work can be a very powerful environment. It may be that you need this intensive and long exposure," said Dr. Richard Suzman of the National Institute on Aging.
The authors say their study adds to a growing body of evidence that when it comes to brain power, you either "use it or lose it" in your retirement years.
Another study reported today in the Wall Street Journal found that bilingual people have a later onset of dementia than people who speak only one language fluently. And while the mind-preserving promises of crossword puzzles and brain games remain scientifically unproven, that hasn't slowed the development of an entire industry to sell them.
Staying at Work Keeps Professor Sharp
80-year-old Rutgers University professor Dan Morgenstern has never even considered retirement, and he thinks his brain is the better for it.
"I am absolutely certain that continuing to work is something that is helping me to keep my mind reasonably alert," said Morgenstern, who has been at work at Rutgers' Jazz Music Institute every day for the past 34 years.
While the study's authors say the causal link between retirement age and cognitive ability is strong, not everyone agrees. Some question whether it's a specific type of work that improves memory, or whether other factors are responsible.
"If it is work, we need to find what aspect of work is causing the retention of memory and cognitive function," said Suzman.