German researchers are challenging what they’re calling the “myth” that a senior’s memory problems are proof of cognitive decline.
“Psychometric tests do not take account of the statistical skew of human experience, or the way knowledge increases with experience,” Universitat Tubingen neurologist Michael Ramscar says. “The human brain works slower in old age, but only because we have stored more information over time.”
In what amounts to a frontal assault on epistemology, Ramscar and his colleagues reviewed thousands of pages of research and test data and even created sophisticated computer simulations to test their theory that a senior’s slower response time, or difficulty recalling names or words, is a reflection of how much information she is carrying, not her capacity to use it.
In the team’s view, “Many of the assumptions scientists currently make about ‘cognitive decline’ are seriously flawed and, for the most part, formally invalid,” Ramscar writes for the team, in the latest edition of Topics in Cognitive Science.
Take, for instance, the matter of birthdays. “We are usually reminded of the birthdays of family members on an annual basis, and this usually makes us good at remembering them,” Ramscar says. “However, as we move through life, we learn about other birthdays. As we learn each new birthday, the mean exposure we have had to all the birthdates we know declines, and the task of recalling a particular birthday becomes more complex.”
That’s not to say that seniors’ cognitive abilities aren’t vulnerable to diseases such as dementia, the researchers say. “Our answer is that except in the case of neurological diseases where there is evidence of pathology, there is no neurobiological evidence for any declines in the processing capacities of healthy older adults,” Ramscar says.
Ramscar and his colleagues take particular aim at vocabulary tests, which are often used to test cognition. There are millions of words in the English language, which means, among other things, that “any English speaker learns only a fraction of the language’s total vocabulary, and that individual speakers’ vocabularies will grow steadily across the life span,” Ramscar writes.
But few vocabulary tests account for older folks’ larger vocabulary, and instead measure their cognitive skills by how quickly they can recall low-frequency words or phrases, he says.
Ramscar and his team ran models where the computer was given a steady rate of new words to “learn.”
Using what they called “a conservative reading rate,” the researchers assumed that the typical adult learned to read by age nine and read 85 words per minute, for 45 minutes per day over 100 days in a year.
The models were then set up so that one would simulate a 21-year-old (with 12 years of reading experience), the other a 70-year-old (with 61 years of reading experience). When the simulations were run, the “21-year-old” had scanned 1.5 million word tokens at that rate, the “70-year-old,” 29 million word tokens.
When given straightforward vocabulary tests, the “older” machine had much slower response times than the younger ones, Ramscar says.
As the world population ages, Ramscar and his colleagues say they’re worried that the pernicious ideas of aging—what he calls “the myth of cognitive decline”—are “exerting a strong, negative influence on the lives of many millions of older adults.”
“We hope this can change,” Ramscar says. “At the outset, we noted that population aging is seen as a problem because of the fear that older adults will be a burden on society; what is more likely is that the myth of cognitive decline is leading to an absurd waste of human potential and human capital.”
The German team’s findings are music to the ears of advocates for the elderly such as Frank Romano. Romano sits on the American Health Care Association Board of Governors and has long advocated for the dignity of long term care residents.
“This study highlights that while we know much about cognition and the aging process, we also still have much to learn in this exciting field,” he says. “It also reminds us to challenge our yardsticks and our perspectives—to recall the richness of the aging experience, to remember that it’s not synonymous with decline in abilities, and that our elders are an important and often undervalued resource.”