“The Cognitive Upside of Aging” is an article by Alexandra Michel in the February 2017 “Observer”, a publication of the Association for Psychological Science (APS). This article corrects some major misconceptions about memory and aging. This realization is important as the expectation is that “the next ten years will witness an increase of about 236 million people aged 65 or older throughout the world.”
A 2014 survey on perceptions of brain health and aging conducted by the AARP found that people believed that the brain peaks at age 29 before beginning to deteriorate by age 53. Now these are opinions regarding brain health and aging. Actual research on this topic reveals how woefully in error these conceptions are.
Joshua K. Hartshone of Boston College, and Laura Germine of the Harvard Medical School reanalyzed an old set of scores from the Wechsler IQ and memory tests taken by a geographically diverse group of adults in the 1990s. Scores from 2,450 test-takers were divided into 13 age categories representing people between the ages of 16 and 89. The researchers then charted peaks in a variety of cognitive skills, ranging from memory to vocabulary, from adolescence through old age.
There was no single apex in overall cognitive skill. Instead, there was a huge variation in cognitive capabilities across the lifespan. The cognitive peaks were all over the place. Hartshone said that this was the “smoking gun” that it’s not all downhill for the aging brain.
Although these data were important, the pool of participants was too small to make any solid conclusions. Most psychological research is done with people in their late teens and early 20s. Getting people in their 50s, 60s, and 70s into the lab is a major obstacle.
Hartshone and Germine were quite creative in addressing this obstacle. The decided to use viral Internet quizzes. Along with Ken Nakayama of Harvard University Germine founded TestMyBrain.org. This website hosts a variety of short cognitive tests that users can complete within minutes. Since the site’s foundation in 2008, data has been collected from more than 1.7 million volunteers across the country. Hartshone has founded a website called GamesWithWords.org as a “Web-based laboratory” for studying language.
Both Hartshone and Germine thought it important for the tests on the websites to be short and engaging to ensure that participants enjoyed taking each one so much that they would be interested in taking a few more or even forwarding them to friends. They wanted to make taking a cognitive battery just as easy and fun as taking one of the not-so-scientific personality tests people like to take on social media sites. More than 3 million people have taken quizzes on the two websites.
In this new set of studies Hartshone and Germine used TestMyBrain.org and GamesWithWords.org to collect large samples of data across five specific cognitive tasks. Three of these tasks, digit symbol coding, verbal working memory, and vocabulary, overlapped with the tasks from the Wechsler exam used in the previous study. The researchers also included a widely used test of emotional perception, which was not included in the original Wechsler tests.
These test data collected from online participants shows a very clear picture of cognitive peaks across the lifespan, one that largely matched the same pattern of results from the decades-old Wechsler tests. Information processing speed crested early in life, around the age of 18 or 19. Short-term memory improved until age 25 before beginning to decline around 35.
However, many cognitive proficiencies, vocabulary, math, general knowledge, and verbal comprehension did not peak until much later in life. These results make sense because people should continue to learn new things and gather new experiences as they age. These skills are usually regarded as belonging to crystalized intelligence. Vocabulary skills had no single high point and continued to improve well into participants’ late 60s and early 70s. The Wechsler data show vocabulary skills topping out mostly in the 40s. To reconcile these results Germine and Hartshone inconcluded the General Social Survey, which has been testing people’s vocabularies for decades. These data confirmed that there really has been a steady shift in vocabulary performance over the last few decades.
Germine and Hartshone wrote, “With the increase in the proportion of adults engaged in cognitively demanding careers, it may be that ages of peak performance are later in the more recent Internet sample, particularly for vocabulary. This could be related to the Flynn effect that IQ has increased steadily in modern times, possibly because of increasing amounts of time devoted to mental activity.”
The Flynn Effect refers to the need to recalibrate the IQ test so that they would have a mean of 100. For years, Flynn argued that this must be some sort of artifact. See the healthy memory blog post “More on Flynn and the Flynn Effect” to learn how Flynn decided that this increase was real and not an artifact. Moreover, he attributed it not just to the amount, but also to the types of cognitive processing people were doing.
Emotional skill also improved with age. To test this ability, researchers asked participants to identify the mood of a person based only on a photograph of the individual’s eyes. A menu provided a selection of potential options such as fearful, tentative, or playful for each photograph. Adults in their 40s and 50s consistently outperformed much younger adults. This ability had a much longer plateau than any of the other cognitive skills that were tested. Germaine and Hartshone wrote “The peak in emotion-recognition ability was also much broader than any of the other tasks, which reflects a long period of relative stability in performance between the ages of 40 and 60 years.”
The researchers recruited another large set of more than 18,000 online participants between the ages of 10 and 73 to confirm their visual and verbal working-memory findings. The replication found the same pattern of cognitive peaks as the other experiments.
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