Adults over 70 with higher levels of education forgot words at a greater rate than those with less education, according to a new study from the University of Southern California.
The findings, published in the current issue of Research on Aging, suggest that after age 70, educated adults may begin to lose the ability to use their schooling to compensate for normal, age-related memory loss.
Study director Eileen Crimmins of the USC Leonard Davis School of Gerontology says she wouldn't recommend halting any schooling based on the results. But they help us understand the way we learn and unlearn as we age.
"We are starting to find evidence of how the brain works over the entire lifecycle," said Crimmins. "This study clarifies that while cognitive performance in old age is related to early life education; not all aspects of cognitive performance relate to education in the same way."
More education is consistently related to better cognitive performance in older adults and in this study, too, individuals with higher levels of education had a higher ability at any given age. However, it was those with the highest education whose performance dropped the most.
"Even though we find in this research that those with higher education do better on mental status tests that look for dementia-like symptoms, education does not protect against more normal, age-related declines, like those seen on memory tests," said lead author Dawn Alley of the University of Pennsylvania, who conducted the research while a doctoral student at the USC Davis School.
Verbal memory was tested by immediate and delayed recall, which consisted of 10 common nouns read aloud by the interviewer, followed by a request for respondents to remember as many nouns as possible from the list. Five minutes later, participants were asked how many of the words they could recall.
Data came from the Asset and Health Dynamics of the Oldest Old (AHEAD) study, a nationally representative longitudinal study of older Americans. Participants, born in 1923 or earlier, were interviewed up to four different times through 1993 and 2000.
Researchers note that while the excess decline among those with more education is small, it is significant. However, they caution that other factors could account for the difference, such as the possibility that less educated adults had a greater rate of decline earlier in life, before the data was collected.
Kristen Sellers, of the National Women's Health Action Network, also contributed to the study while a USC doctoral student.