When does your intelligence peak?

When Does Your Intelligence Peak?

Luci Gutiérrez

“It’s not true that no one needs you anymore.”

These words came from an elderly woman sitting behind me on a late-night flight from Los Angeles to Washington, D.C. The plane was dark and quiet. A man I assumed to be her husband murmured almost inaudibly in response, something to the effect of “I wish I was dead.”

Again, the woman: “Oh, stop saying that.”

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I didn’t mean to eavesdrop, but couldn’t help it. I listened with morbid fascination, forming an image of the man in my head as they talked. I imagined someone who had worked hard all his life in relative obscurity, someone with unfulfilled dreams—perhaps of the degree he never attained, the career he never pursued, the company he never started.

At the end of the flight, as the lights switched on, I finally got a look at the desolate man. I was shocked. I recognized him—he was, and still is, world-famous. Then in his mid‑80s, he was beloved as a hero for his courage, patriotism, and accomplishments many decades ago.

As he walked up the aisle of the plane behind me, other passengers greeted him with veneration. Standing at the door of the cockpit, the pilot stopped him and said, “Sir, I have admired you since I was a little boy.” The older man—apparently wishing for death just a few minutes earlier—beamed with pride at the recognition of his past glories.

When Do Your Mental Powers Peak in Life?

When Does Your Intelligence Peak?

Frazer Hudson / Getty Images

At what point in your life do different mental powers peak? Some of the earliest intelligence tests simply categorized all people over the age of 16 as “adults.” Today, researchers recognize that the brain continues to develop and change throughout early adulthood and that there are significant changes in how the brain functions as people age.

Still, we often tend to think of the adult brain as a relatively stable and unchanging thing, suggesting that various mental abilities are simply static, or even on the decline, throughout most of adulthood. Conventional ideas about intelligence often suggest that people hit their mental peak fairly early in life and then follow a long, slow decline into old age.

There is also a tendency to believe that certain mental abilities, such as fluid intelligence, typically peak relatively early in adulthood. Crystallized intelligence, on the other hand, is often suggested to peak during late adulthood.

According to some experts, this long-held dichotomy might be far too simplistic. Researchers Joshua Hartshorne and Laura Germine utilized a large pool of online participants to gather information about exactly what ages certain mental abilities are the strongest. What they discovered was that there was a surprising consistency to when particular abilities typically peak.

According to the study published in the journal Psychological Science, different aspects of fluid intelligence peak at different ages, with some abilities hitting their apex 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’ve peaked on most things, much less all of them,” explained researcher Joshua Hartshorne of MIT and one of the study's authors.

Hartshorne had previously found that visual short-term memory peaks in the mid-30s before beginning to go down. In a 2011 study, Germine found that the ability to recognize faces also improves until people are in their early 30s and then begins to gradually decline.

Digging deeper, the two began looking at archival data from older intelligence tests. What they discovered was that there appeared to be no single mental peak. Instead, different abilities seemed to peak at wildly different and sometimes surprising ages. These results helped inspire their further investigation into how mental abilities change with age.

The latest study was able to draw on a large online sample of participants who utilized the websites gameswithwords.org and testmybrain.org. Using the approach, the researchers were able to gather data from nearly 50,000 people across a wide range of ages.

Four different types of cognitive tasks were used as well as one task that looked at the ability to detect the emotional states of other people.

Hartshorne and Germine's earlier research had shown that these tasks measured mental abilities that change as people age.

The results revealed what the researchers called “considerable heterogeneity in when cognitive abilities peak.”

Among the key findings from the latest study and earlier research:

  • 18-19: Information-processing speed peaks early, then immediately begins to decline.
  • 25: Short-term memory gets better until around age 25. It remains fairly steady until it begins to decline around age 35.
  • 30: Memory for faces peaks and then starts to gradually decline.
  • 35: Your short-term memory begins to weaken and decline.
  • 40s-50s: Emotional understanding peaks in middle to later adulthood.
  • 60s: Vocabulary abilities continue to increase.
  • 60s and 70s: Crystallized intelligence, or accumulated knowledge and facts about the world, peaks late in life.

While the results that crystallized intelligence peaks later in life are consistent with earlier findings, this study implies that this peak occurs much later in life than previously believed.

What could explain this late peak in mental abilities? The researchers suggest that their results might be due to the fact that people today have more education, greater access to information, and more mentally demanding jobs than did previous generations of adults.

When Does Intelligence Peak?

When does cognitive functioning peak? As we get older, we certainly feel as though our intelligence is rapidly declining.

(Well, at least I do!) However, the nitty gritty research on the topic suggests some really interesting nuance.

As a recent paper notes, “Not only is there no age at which humans are performing at peak on all cognitive tasks, there may not be an age at which humans perform at peak on most cognitive tasks.”

In one large series of studies, Joshua Hartshorne and Laura Germine presented evidence from 48, 537 people from standardized IQ and memory tests.

The results revealed that processing speed and short-term memory for family pictures and stories peak and begin to decline around high school graduation; some visual-spatial and abstract reasoning abilities plateau in early adulthood, beginning to decline in the 30s; and still other cognitive functions such as vocabulary and general information do not peak until people reach their 40s or later.

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When Does Your Intelligence Peak? Credit: “When Does Cognitive Functioning Peak? The Asynchronous Rise and Fall of Different Cognitive Abilities Across the Life Span”, by Joshua Hartshorne and Laura Germine, in Psychological Science, March 13, 2015

The Dark Matter of Intelligence

The picture gets even more complicated, however, once we take into account the “dark matter” of intelligence. As Phillip Ackerman points out, should we really be judging adult intelligence by the same standard we judge childhood intelligence? At what point does the cognitive potential of youth morph into the specialized expertise of adulthood?

In the intelligence field, there is a distinction between “fluid” intelligence (indexed by tests of abstract reasoning and pattern detection) and “crystallized” intelligence (indexed by measures of vocabulary and general knowledge). But domain-specific expertise—the dark matter of intelligence—is not identical to either fluid or crystallized intelligence.

Most IQ tests, which were only every designed for testing schoolchildren, don't include the rich depth of knowledge we acquire only after extensive immersion in a field. Sure, measured by the standards of youth, middle-aged adults might not be as intelligent as young adults, on average.

But perhaps once dark matter is taken into account, middle-aged adults are up to par.

To dive deeper into this question, Phillip Ackerman administered a wide variety of domain-specific knowledge tests to 288 educated adults between the ages of 21 and 62.

Domains included art, music, world literature, biology, physics, psychology, technology, law, astronomy and electronics. Ackerman found that in general, middle-aged adults are more knowledgeable in many domains compared with younger adults.

As for the implications of this finding, I love this quote from the paper:

“[M]any intellectually demanding tasks in the real world cannot be accomplished without a vast repertoire of declarative knowledge and procedural skills.

The brightest (in terms of IQ) novice would not be expected to fare well when performing cardiovascular surgery in comparison to the middle-aged expert, just as the best entering college student cannot be expected to deliver a flawless doctoral thesis defense, in comparison to the same student after several years of academic study and empirical research experience. In this view, knowledge does not compensate for a declining adult intelligence; it is intelligence!”

There was an important exception to Ackerman's finding, however. All three science-related tests (chemistry, physics and biology) were negatively associated with age. Tellingly, these three tests were most strongly correlated with fluid intelligence. This might explain why scientific genius tends to peak early.

Nevertheless, on the whole, these results should be considered good news for older adults.

Unless you're trying to win the Nobel prize in physics at a very old age, there are a lot of domains of knowledge that you can continue to learn in throughout your life.

What's more, Ackerman found that certain measures of personality, such as intellectual curiosity, were related to domain-specific knowledge above and beyond the effects of standard measures of intelligence.

And even if you do want to maintain your fluid intelligence as long as possible, there is recent research suggesting that having a greater purpose in life can help protect against cognitive decline among older adults.

Giyeon Kim and colleagues combined seven items looking at various aspects of purpose, including plans for the future, importance of daily activities, dedication to ensure plans made are actualized in the future, a good sense of what one wishes to accomplish in life, whether one has accomplished all one wishes to accomplish in life, whether one cares about the future, and whether one has a sense of direction and purpose in one's life. They found that after adjusting for covariates, purpose in life acted as a protective factor against cognitive decline.* The researchers argue that purpose in life could be used as a treatment technique for cognitive decline in clinical settings.

Their research adds to a growing literature showing the many benefits of maintaining a purpose in life for health and well-being.

Greater purpose in life has been linked to reduced all-cause mortality and cardiovascular problems, increased longevity, maintenance of general physical functioning, reduced risk of stroke and reduced incidence of sleep disturbances.

One longitudinal study over a 10-year period found that increased meaning in life was associated with lower allostatic load (the “wear and tear on the body”). This is important considering that allostatic load has also been positively linked with increased risk of diseases, mortality and cognitive decline.

The good news for older adults is that not only can we continue to acquire domain-specific knowledge into older age, but purpose in life is also modifiable. It seems that the question “When does intelligence peak?” is actually a rather meaningless question.

Not only do our various cognitive functions peak at different times, but past a certain age it might make more sense to view adult intelligence not through the lens of youthful general processing speed and reasoning, but through the lens of expertise, wisdom and purpose.

At What Age Do Our Intellectual Abilities Peak?

March 28, 2015 4 min read Opinions expressed by Entrepreneur contributors are their own.

When it comes to ability, conventional wisdom says age matters.

At one end of the spectrum is the belief that mental sharpness peaks early, a viewpoint enforced by the college-aged entrepreneurs currently raising billions in Silicon Valley.

Meanwhile, there exists a simultaneous, parallel narrative, one that equates experience with intelligence (consider that we've never elected a U.S. president younger than 43, and aren't legally allowed to elect anyone under 35).

From a cognitive standpoint, which position holds more sway? Do our intellectual abilities peak in our mid-20s, or do they continue to ripen with age?

According to a recent study published in Psychological Science, the answer is yes to both.

When neuroscientists at MIT and Massachusetts General Hospital gathered data from nearly 50,000 individuals aged 10 to 71 on a wide variety of online cognitive tasks, they found substantial variances in the relationship between age and intellectual abilities.

Performance on processing speed, for example, peaked and began to decline early, around high school graduation; verbal and visual working memory tasks plateaued in the mid-30s; emotion-perception gradually crested in late middle-age.

Finally, vocabulary continued to steadily climb into the 60s and beyond.

Related: How Old Is Too Old to Start a Business? The Answer May Surprise You. (Infographic)

“These findings motivate a nuanced theory of maturation and age-related decline, in which multiple, dissociable factors differentially affect different domains of cognition,” the authors write.

“On the practical side, not only is there no age at which humans are performing at peak on all cognitive tasks, there may not be an age at which humans perform at peak on most cognitive tasks.

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This view of human ability – one that recognizes the existence of multiple, co-existing intelligences, each with its own individual life-cycle — helps explain why many personal renaissances arrive later in life: Harland Sanders started KFC his 60s, Ray Kroc opened McDonald’s in his early 50s, Steve Jobs spearheaded the iPod, iPhone, iPad and iMac after the age of 45.

Of course, certain abilities do, in fact, favor the young. “A lot of what it comes down to — are you cognitively able to do it?” James C. Kaufman, a professor of educational psychology at the University of Connecticut, recently told The New York Times. “Most software developers don’t suddenly start at 60.

”  Attempting to develop a new skill at an age where your ability is already waning, the deck is literally stacked against you.

“It is generally very difficult to get a late start in a field that requires lots of fluid intelligence from the get-go,” Dean Keith Simonton, a professor of psychology at the University of California, Davis told the outlet.

Related: 8 CEOs Who Amassed a Fortune Before Age 30 (Infographic)

This, of course, gets at the root of Silicon Valley's youth obsession; some of the bias is founded in fact. But the blanket statements often bandied about – “people under 35 are the people who make change happen…people over 45 basically die in terms of new ideas,” venture capitalist Vinod Khosla famously pronounced – are oversimplifications.  

Engineering, programming and coding are skills ideally acquired before middle-age, but entrepreneurship itself is not a profession reserved for the young. A recent report from the Kauffman Index of Entrepreneurial Activity found that the highest rate of entrepreneurial activity in the U.S.

happens in the 45-54 age bracket, with a considerable amount occurring in the 55-64 demographic.

Meanwhile, when a team of researchers looked into the backgrounds of 502 successful engineering and technology American companies founded between 1995 and 2005, they discovered that the median age of their founders was a nearly middle-aged 39.

When Does Your Intelligence Peak?

We know that from early childhood to adulthood our intelligence grows and that after a certain point in adulthood our ability to learn declines. It is a commonly held belief that our intelligence and capacity to learn increases until we reach adulthood, but when does our intelligence peak? 

Part of the answer to the question requires addressing and defining the different types of intelligence. We must also consider the way the brain grows and changes throughout different stages of development. The answer is complicated, but ultimately, different types of intelligence peak at different ages. 

At what ages do different types of intelligence peak?

According to this study, the following is an approximate indication of the ages when different types of intelligence peak. Of course, the ages will vary depending on personal life experiences. 

  • Late teens/early twenties: Information-processing peaks and starts to rapidly decline.
  • Mid-twenties: Short-term memory improves until about 25 and is mostly steady until it starts to decline near the age of 35.
  • Thirties: Facial recognition peaks and starts to slowly decline.
  • Mid-thirties: Short-term memory starts to decline.
  • Forties-Fifties: Emotional intelligence peaks.
  • Sixties: Vocabulary ability continues to increase.
  • Sixties and seventies: Accumulated knowledge (or crystallized intelligence) peaks.
  • Fluid intelligence and crystallized intelligence

According to this article, crystallized intelligence refers to our ability to use already accumulated experience, knowledge, and skills. Research suggests that the older we get, the more our crystallized intelligence grows. Fluid intelligence refers to using reason and problem-solving skills in new or unique situations. 

While fluid intelligence peaks during young adulthood, crystallized intelligence continues to grow and peaks later in life. So while we may be more capable of absorbing new information, thinking more quickly, and solving new problems at a younger age, we have stronger vocabularies, higher emotional intelligence, and more overall knowledge when we are older. 

The good news

This information goes against the commonly held belief that we are more intelligent and capable of learning at a young age and then slowly decline once we reach adulthood.

The research clearly shows that our intelligence does not peak during young adulthood except for a few specific types of intelligence.

This is possibly due to the fact that humans in today’s world have more access to information, are better educated, and have jobs that require more brainpower than ever before. 

The takeaway

At every age, certain types of intelligence are reaching their peak, some are increasing, and some are declining. At no one point or age are we at the peak of all types of intelligence, so technically there is no peak age for the wide umbrella of the term “intelligence.” 

Also, the above chart may not even be accurate for many people. Data from old intelligence tests reveal that different skills and types of intelligence peaked at various and surprising ages.

There is no one size fits all model of intelligence, including at what age it peaks.

More studies will need to be conducted to try to determine if there is any more conclusive common link between age and the different types of intelligence.

At What Age Does Your Brain Peak?

(Photo: Anita Ponne/Shutterstock)

Sports writers will tell you that athletes peak in their 20s, after which point their skills quickly erode. Most other things in our lives—our careers, for example—take a good deal more time to develop.

Intelligence, it turns out, peaks a bit later, too, though with a twist, according to a recent study: Some facets of intelligence peak when we're still in high school or college, while others continue to improve into our 40s, 50s, and beyond.

Research on intelligence began a century ago with French psychologist Alfred Binet's work aimed at identifying schoolchildren with learning disabilities in the early 1900s. For a while, psychologists focused on how they could measure intelligence.

 But more recently, psychologists have been interested in what makes a person intelligent, or, for that matter, whether there is even one single thing we could call intelligence. (Probably not.) As the latter idea's taken hold, researchers have wondered how different sorts of intelligence develop over time.

Answering that question has implications not only for scientists' theories of intelligence, but could also improve teachers' effectiveness, and help doctors identify and address cognitive decline in senior citizens.

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To get some answers, psychologists Joshua Hartshorne and Laura Germine tested 21,926 people aged 10 to 71 who had visited the website TestMyBrain.org.

There, participants were tested on vocabulary, the ability to encode strings of numbers into symbols, something called the “mind in the eyes” test, an emotion-recognition test which asks people to identify someone's feelings using only a picture of their eyes, and working memory—that is, the ability to recall recently viewed objects.

The study aims to show that cognitive abilities don't all peak at the same time or even follow any one trend as people age

Depending on which of those given measures you're going by, people peak at very different times. Some of the youngest participants did best on the number-to-symbol coding task, with the peak performance around 19 or 20 years old. After that, performance steadily declined with age. Working memory peaked between the mid 20s to mid 30s before beginning a relatively slow decline.

Those over 40 shouldn't fret, though. On the “mind in the eyes” test, participants reached near-maximum abilities by their early 20s but kept improving until 48, after which emotion-recognition skills declined very slowly. Vocabulary, meanwhile, climbed with the participants' age, and gave little sign of slowing down.

This Is The Age You Reach Peak Intelligence, According to Science

There are a lot of skills that peak in your 20s. By the time most of us hit 30, it's likely that our best sport, drinking and memorising days are over. And it's generally thought that our ability to think on our feet and quickly recall information declines as we get older too.

But now new research has shown that not all aspects of intelligence age in the same way, and while some peak during high school and college, others continue to improve after 40.

To investigate how intelligence changes with age, psychologists from Massachusetts Institute of Technology (MIT) and the Massachusetts General Hospital in the US tested 48,537 people between the ages of 10 to 89 who had visited the sites GamesWithWords.org and TestMyBrain.org, where they conducted language, IQ and memory tests that measured their emotion-recognition, working memory, number skills and vocabulary.

They found that, depending on your definition of 'intelligence', the skills peak at very different times throughout your life. While young participants mostly did the best on the number-to-symbol coding tasks, with a peak age of around 19 to 20 years old, working memory peaked between the mid-20s and mid-30s, before starting to slowly decline.

And while 20-somethings were really good at recognising someone's emotions from simply looking at a photo of their eyes, this ability kept improving all the way up until the age of 48, after which the skill dropped very, very slowly. Vocabulary just kept getting better with age, finally peaking in the 60s or 70s, without any obvious sign of decline.

The results, which have been published in Psychological Science, highlight the fact that different parts of our intelligence peak at different times throughout our lives, according to the authors, Joshua K. Hartshorne and Laura T. Germine.

  • As Hartshorne explained in an MIT press release: “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.”
  • “It paints a different picture of the way we change over the lifespan than psychology and neuroscience have traditionally painted,” added Germine.
  • Source: Pacific Standard Magazine

The rise and fall of cognitive skills

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.”

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