• Researchers have been running large-scale experiments on the Internet, where people of any age can become research subjects. Their websites feature cognitive tests designed to be completed in just a few minutes. Shown here is a

    Researchers have been running large-scale experiments on the Internet, where people of any age can become research subjects. Their websites feature cognitive tests designed to be completed in just a few minutes. Shown here is a "pattern completion test" inspired by their website, testmybrain.org.

    Illustration: Jose-Luis Olivares/MIT

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The rise and fall of cognitive skills

Researchers have been running large-scale experiments on the Internet, where people of any age can become research subjects. Their websites feature cognitive tests designed to be completed in just a few minutes. Shown here is a "pattern completion test" inspired by their website, testmybrain.org.

Neuroscientists find that different parts of the brain work best at different ages.


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Scientists have long known that our ability to think quickly and recall information, also known as fluid intelligence, peaks around age 20 and then begins a slow decline. However, more recent findings, including a new study from neuroscientists at MIT and Massachusetts General Hospital (MGH), suggest that the real picture is much more complex.

The study, which appears in the journal Psychological Science, finds that different components of fluid intelligence peak at different ages, some as late as age 40.

“At any given age, you’re getting better at some things, you’re getting worse at some other things, and you’re at a plateau at some other things. There’s probably not one age at which you’re peak on most things, much less all of them,” says Joshua Hartshorne, a postdoc in MIT’s Department of Brain and Cognitive Sciences and one of the paper’s authors.

“It paints a different picture of the way we change over the lifespan than psychology and neuroscience have traditionally painted,” adds Laura Germine, a postdoc in psychiatric and neurodevelopmental genetics at MGH and the paper’s other author.

Measuring peaks

Until now, it has been difficult to study how cognitive skills change over time because of the challenge of getting large numbers of people older than college students and younger than 65 to come to a psychology laboratory to participate in experiments. Hartshorne and Germine were able to take a broader look at aging and cognition because they have been running large-scale experiments on the Internet, where people of any age can become research subjects.

Their web sites, gameswithwords.org and testmybrain.org, feature cognitive tests designed to be completed in just a few minutes. Through these sites, the researchers have accumulated data from nearly 3 million people in the past several years.

In 2011, Germine published a study showing that the ability to recognize faces improves until the early 30s before gradually starting to decline. This finding did not fit into the theory that fluid intelligence peaks in late adolescence. Around the same time, Hartshorne found that subjects’ performance on a visual short-term memory task also peaked in the early 30s.

Intrigued by these results, the researchers, then graduate students at Harvard University, decided that they needed to explore a different source of data, in case some aspect of collecting data on the Internet was skewing the results. They dug out sets of data, collected decades ago, on adult performance at different ages on the Weschler Adult Intelligence Scale, which is used to measure IQ, and the Weschler Memory Scale. Together, these tests measure about 30 different subsets of intelligence, such as digit memorization, visual search, and assembling puzzles.

Hartshorne and Germine developed a new way to analyze the data that allowed them to compare the age peaks for each task. “We were mapping when these cognitive abilities were peaking, and we saw there was no single peak for all abilities. The peaks were all over the place,” Hartshorne says. “This was the smoking gun.”

However, the dataset was not as large as the researchers would have liked, so they decided to test several of the same cognitive skills with their larger pools of Internet study participants. For the Internet study, the researchers chose four tasks that peaked at different ages, based on the data from the Weschler tests. They also included a test of the ability to perceive others’ emotional state, which is not measured by the Weschler tests.

The researchers gathered data from nearly 50,000 subjects and found a very clear picture showing that each cognitive skill they were testing peaked at a different age. For example, raw speed in processing information appears to peak around age 18 or 19, then immediately starts to decline. Meanwhile, short-term memory continues to improve until around age 25, when it levels off and then begins to drop around age 35.

For the ability to evaluate other people’s emotional states, the peak occurred much later, in the 40s or 50s.

Christopher Chabris, an associate professor of psychology at Union College, said a key feature of the study’s success was the researchers’ ability to gather and analyze so much data, which is unusual in cognitive psychology.

“You need to look at a lot of people to discover these patterns,” says Chabris, who was not part of the research team. “They’re taking the next step and showing a more fine-grained picture of how cognitive abilities differ from one another and the way they change over time.”

More work will be needed to reveal why each of these skills peaks at different times, the researchers say. However, previous studies have hinted that genetic changes or changes in brain structure may play a role.

“If you go into the data on gene expression or brain structure at different ages, you see these lifespan patterns that we don’t know what to make of. The brain seems to continue to change in dynamic ways through early adulthood and middle age,” Germine says. “The question is: What does it mean? How does it map onto the way you function in the world, or the way you think, or the way you change as you age?”

Accumulated intelligence

The researchers also included a vocabulary test, which serves as a measure of what is known as crystallized intelligence — the accumulation of facts and knowledge. These results confirmed that crystallized intelligence peaks later in life, as previously believed, but the researchers also found something unexpected: While data from the Weschler IQ tests suggested that vocabulary peaks in the late 40s, the new data showed a later peak, in the late 60s or early 70s.

The researchers believe this may be a result of better education, more people having jobs that require a lot of reading, and more opportunities for intellectual stimulation for older people.

Hartshorne and Germine are now gathering more data from their websites and have added new cognitive tasks designed to evaluate social and emotional intelligence, language skills, and executive function. They are also working on making their data public so that other researchers can access it and perform other types of studies and analyses.

“We took the existing theories that were out there and showed that they’re all wrong. The question now is: What is the right one? To get to that answer, we’re going to need to run a lot more studies and collect a lot more data,” Hartshorne says.

The research was funded by the National Institutes of Health, the National Science Foundation, and a National Defense Science and Engineering Graduate Fellowship.


Topics: Brain and cognitive sciences, Aging, Memory, Research, School of Science, National Institutes of Health (NIH), National Science Foundation (NSF)

Comments

Aging is inevitable. Staying healthy should be a priority for every aging adult. Be physically active, stay mentally sharp, remain socially engaged and follow a good diet. Staying healthy can help reduce illness and injury and also reduce medical costs. I recently found the site Retirement And Good Living which has many pages and posts about aging, health, fitness and nutrition and several games and health calculators.

In early age, long-term memory maybe important,which provide young people basic knowledge to survive.

Interesting research, would also be curious to know if the same logic would apply to people with Autism or Asperger's where they have challenges with regards to understanding and processing of emotions, if yes then it opens up a window of hope going forward for these individuals and for people who are working with these differently abled individuals

well at 64, I still have high speed mental and cognative abilities far above the normal that I meeet in my daily worklife.....I hoping I havent peaked as yet.....:O)

Good to hear that vocabulary peaks between 60/70. Being 65 and becoming a writer seems to be realistic. I am sure many of the e-mail reactions on articles in the NYC are from this age group: they have lots of time left

Hello, thank you for this stunning article. But could it be that the
test you talke about (Weschler IQ tests) is not written "Weschler" but
"Wechsler"? More information about Wechsler Adult Intelligence Scale you can find here: https://en.wikipedia.org/wiki/...

Very interesting. Following up, how are these study findings similar to and different from the Schaie study findings (Seattle Longitudinal Study?) And the data are cross sectional, correct? And the sample reflects adults who play online "brain food" games, correct?

Since the testing was done over a relatively short period (essentially a snapshot in time), how does one distinguish between the twin possibilities that
1. vocabulary skills peak during one's late 60's or early 70's, or
2. those who are now in their late 60's and early 70's were exposed to some factor in their pasts that fostered better vocabulary skills than those of other ages?
The conclusion seems analogous to looking at a photo-finish from a horse race and concluding that the winner passed the runners-up as they came down the stretch.

Isn't Psychological Science an oxymoron?

Great article, as a psychologist I feel the need to clarify the authors description of fluid reasoning. In particular, her description of this process as "..our ability to think quickly and recall information" is not entirely accurate. Broadly speaking, current theories of psychological processing define our ability to think quickly as processing speed. The broad ability to recall information is better understood as short-term memory and/or long-term storage and retrieval, depending on context. By all means, processing speed, short-term memory, and long-term storage/retrieval are necessary in order for the brain to effectively "reasoning fluidly." However, it is erroneous to describe fluid reasoning as consisting of these abilities alone. Rather, fluid reasoning is best described as the deliberate but flexible control of attention to solve novel "on the spot" problems that cannot be performed by relying on previously learned habits, schemas, scripts, or knowledge.

In addition, she mentions that the findings from Germine's study about facial recognition do not align well with previous theories of fluid reasoning. However, this statement should be clarified and expounded upon as the ability to recognize faces cannot be attributed solely to fluid reasoning. Indeed, fluid reasoning comes into play when our brains recognize faces, but the skill is more attributed to long-term storage and retrieval (as well as the brains visual-recall pathways). I know, I know; this is all rather trivial to point out. That said, it should be noted that all psychological processes are active to some extent during moment to moment human existence.

Interesting research! Was there any examination of when the ability to use Piagetian formal operations peaked? Did that ability decline after a certain age? For sure not many actually get that ability at any age, but I wonder if those who do lose it at some point. Nevertheless, that kind of cognitive ability is pretty crucial and fundamental to innovation and socio/technological progress.

As a novelist, I am delighted to learn that my crystallized intelligence is peaking right about now. If only I could convince my teenage children of this.

--Larry Constantine, '67 (pen name, Lior Samson)

I should think some of the findings might result from evolutionary pressures -- particularly the survival value of certain skills at certain ages. For example, it clearly has survival value for the infant if his/her parents recognize him/her as theirs, and don't waste their scarce resources on similar looking other infants in the troop. So good facial recognition skills may be more "needed" during that point in life when you are bearing & raising small children. High in the twenties and maybe peaking (with practice?) in the early thirties?

Nice to see someone who doesn't jump to a single binary conclusion, nor conflate correlation with causation. Though the University methodology cynic in me says "we're going to need to run more studies" can be translated as "give us several years more funding". Perhaps data can be correlated from other studies and research experiments.

my new research progress about, neuron relation to light,it has similarity to light wave, I identify a new phenomena, a new kind of Nero communication, in insects, honeybee, fruit fly ants they are conscious, like human, their neurons are very few with compare human, another example the Nero communication of gellyfish, my another research also provides the light speed variation in expanding universe. so further search for the transformed geometric shape of light waves in expanding universe. it may belong to another universe.
human evoluted neurons are conceptualised a new light wave communication during the Nero fire. algorithm may have given the sequence of Nero data transformation to the storing memory

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