Nobody wants to be a number. But there is one number that probably says a lot about you, whether you know it or not: your IQ, or intelligence quotient.(President Donald Trump recentlybragged to Forbes that he would "win" if his IQ test score was compared to that of his Secretary of State, Rex Tillerson.)
IQ is often dismissed as antiquated, misguided, or less important than personality traits. But according to Stuart Ritchie, an intelligence researcher at the University of Edinburgh, there's a massive amount of data showing that it's one of the best predictors of someone's longevity, health, and prosperity. And psychologists have been able to replicate these findings over and over.
(Richie and I go further into why IQ research makes some people uncomfortable in a Q&Ahere.)
In a new book, Intelligence: All that Matters, Ritchie persuasively argues that IQ doesn't necessarily set the limit for what we can do, but it does give us a starting point. And the truth is some people start ahead.
Here are nine facts that help explain IQ and why it matters.
(Most of these charts have been pulled from Intelligence: All that Matters. It's a spry, uncluttered read if you're interested in learning more.)
1) Most people have average intelligence
The first thing to know about IQ is that it is a composite score made up of the results of many different tests of reasoning, memory, acquired knowledge, and mental processing speed. These sub-scores are totaled, and are then compared with those of the rest of the population. A perfectly average score is set at 100.
Note: A full IQ test is an hour-plus, intense process. It needs to be administered by a trained tester, and certain portions are timed. Those free quizzes you see online are not legitimate IQ tests.
Like other variable human traits (height, for example), the range of IQ is on a standard curve bell curve.
Most people you meet are probably average, and a few are extraordinarily smart. Just 2.2 percent have an IQ of 130 or greater.
What's fascinating is that people who score well on one of the tests tend to score well on them all. So your score on a task on how fast you can turn off a blinking light (one component of some intelligence tests) is correlated with your scores on verbal and spatial reasoning.
Psychologists call this overlap of scores the "G," or general intelligence, factor.
"The classic finding — I would say it is the most replicated finding in psychology — is that people who are good at one type of mental task tend to be good at them all," Ritchie says.
Where or how "G" exists in the brain isn't well-understood. But no matter how it arises, the G-factor is real in the sense it can predict outcomes in our lives — how much money you'll make, how productive of a worker you might be, and, most chillingly, how likely you are to die an earlier death.
2) Having a higher IQ protects you from death
This is an uncomfortable one: According to the research, people with high IQs tend to be healthier and live longer than the rest of us. This graph represents a study of 1 million Swedish men. The researchers found a threefold difference in the risk of death between the those with the highest IQs and those with the lowest.
There are a few interrelated reasons why this may be. One is the fact that people with higher IQs tend to make more money than people with lower scores. Money is helpful in maintaining weight, nutrition, and accessing good health care.
It could also be that people with higher IQs are smart enough to avoid accidents and mishaps. There's actually some evidence to support this: Higher-IQ people are less likely to die in traffic accidents.
3) IQ is correlated with career success and wealth, but not necessarily happiness
Like mortality, the association between IQ and career success is positive. People with higher IQs generally make better workers, and they make more money.
But these correlations aren't perfect.
Correlations are measured from -1 to 1. A correlation of 1 would mean that for every incremental increase in IQ, a fixed increase in another variable (like mortality or wealth) would be guaranteed.
Life isn't that pretty. Many of these correlations are less than .5, which means there's plenty of room for individual differences. So, yes, very smart people who are awful at their jobs exist. You're just less likely to come across them.
With all the perks of a high IQ — wealth, health, longevity — you'd think the severely smart would be happier for it. But that's not necessarily the case.
"The correlation between IQ and happiness is usually positive, but also usually smaller than one might expect (and sometimes not statistically significant)," Ritchie says.
Also know that IQ, generally, is not related to the personality factors that can also get us ahead in life. Of the "Big Five" personality traits, the only linked to IQ is openness to experience. "To some degree smarter people will seek out more experiences and think about things more and enjoy considering ideas," Ritchie says.
(IQ often beats personality when it comes to predicting life outcomes: Personality traits, a recent study found, can explain about 4 percent of the variance in test scores for students under age 16. IQ can explain 25 percent, or an even higher proportion, depending on the study.)
4) You're probably stuck with what you got
Studies have found if you're a smart kid, you'll be a smart old person.
This chart shows a Scottish study where a group of 90-year-olds were given an IQ test they previously took at age 11.
Even though intelligence generally declines with age, those who had high IQs as children were most likely to retain their smarts as very old people.
5) Intelligence peaks in your mid- to late 20s, and then slowly declines
I'm 26 years old. And I'm probably as smart as I'll ever be in life.
After your mid-20s, your "crystallized intelligence" — i.e., accumulated knowledge — plateaus, while your "fluid intelligence" — the ability to solve new problems — starts to drop. Your mental quickness takes an even steeper dive.
Ritchie says understanding these age-related intelligence declines is one of the most important reasons for studying the biology of IQ.
"If we know the genes related to intelligence — and we know these genes are related to cognitive decline as well — then we can start to a predict who is going to have the worst cognitive decline, and devote health care medical resources to them," he says.
6) Around half the variance in IQ can be explained by genetics
Studies comparing identical and fraternal twins find about half of IQ can be explained by genetics.
But what's odd is that genetics seems to become more predictive of IQ with age.
That is, twins' genes seem to be less important for IQ when they're children compared with when they're adults. The reason why isn't entirely understood.
Intelligence researchers Robert Plomin and Ian Deary suggest it may be due to what's known as "genetic amplification," a process in which "small genetic differences are magnified as children select, modify and create environments correlated with their genetic propensities," they write in a 2015 literature review.
Consider this: A child with a genetic propensity to be smart may choose to spend more time in a library. A tiny 6-year-old may not be allowed to go to the library by herself. But a 16-year-old can.
The idea is as we age, we grow more in control of our environments. Those environments we create can then "amplify" the potential of our genes.
7) Genes are not the only thing that matters in intelligence
Genetics doesn't seal your destiny when it comes to IQ. About half the variability in IQ is attributed to the environment. Access to nutrition, education, and health care appear to play a big role.
But overall, the environmental determinants of IQ aren't as well understood as the biology.
"In terms of environment, it’s much harder to pin things down," Ritchie says. "People’s lives are really messy, and the environments they are in are messy. There’s a possibility that a lot of the environmental effect on a person’s intelligence is random."
8) Humans are getting smarter
Hurray! Mean IQ scores appear to be increasing between 2 and 3 points per decade.
This phenomenon is know as the Flynn effect, and it is likely the result of increasing quality of childhood nutrition, health care, and education. (In his book, Ritchie explains, it might also be the result of an increased emphasis on knowledge as the engine of our economy, which has encouraged the type of abstract thinking IQ exams test for.)
9) IQ is increasing faster in developing countries
Some of the greatest gains in IQ are happening in the developing world, where increases in childhood nutrition (namely via iodine supplements) and access to health care have made the greatest difference in IQ.
There's actually some evidence that the Flynn effect may be waning in the developed world. "It might well be we are running out of these low-hanging fruits [like standardized education and nutrition] that we know improve IQ," Ritchie says.
One final note: Know that people with higher IQs aren't better at everything. In fact, they're more likely to need glasses to correct for nearsightedness. Nerds!
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What is the normal IQ for a 9? ›
|Age of Child||Average IQ|
|9 years old||Between 10 and 30|
|10 years old||Between 30 and 50|
|11 years old||Between 30 and 50|
|12 years old||Between 40 and 65|
Meaning of IQ
85 to 115 - Two thirds of us have an IQ in this range: the 'average' IQ is 100. Over 135 - You are in the top 1%.
Although there are no standard IQ levels of intellectual giftedness, some experts suggest the following IQ ranges: Mildly gifted: 115 to 129. Moderately gifted: 130 to 144. ighly gifted: 145 to 159.What IQ is considered genius? ›
Notably, the average IQ score falls between 85 and 115. A score above 140, meanwhile, is considered to be genius level.Is 120 IQ smart? ›
An IQ score over 140 indicates that you're a genius or nearly a genius, while 120 - 140 is classed as "very superior intelligence". 110 - 119 is "superior intelligence", while 90 - 109 is "normal or average intelligence".What is a 95% IQ? ›
The IQ 95 result indicates that you have a normal sort of thinking capacity that falls into the category of "Average Intelligence" in the IQ scale range chart, which accounts for 51.6 percent of the world's population. That suggests you or your child have the same degree of intelligence as the majority of individuals.What IQ is needed for Mensa? ›
The minimum accepted score on the Stanford–Binet is 132, while for the Cattell it is 148 and 130 in the Wechsler tests (WAIS, WISC). Most IQ tests are designed to yield a mean score of 100 with a standard deviation of 15; the 98th-percentile score under these conditions is 131, assuming a normal distribution.Is 120 IQ good for a 12 year old? ›
Scores of 90-109 are Average. Scores of 110-119 are High Average. An IQ of 125 is considered by many schools to be “gifted.” Scores of 120-129 are Superior. And scores above 130 are Very Superior.What is the average American IQ? ›
Psychologists revise the test every few years in order to maintain 100 as the average. Most people (about 68 percent) have an IQ between 85 and 115. Only a small fraction of people have a very low IQ (below 70) or a very high IQ (above 130). The average IQ in the United States is 98.Does IQ increase with age? ›
Abilities change, but IQ scores tend to be very stable. However the intelligence ability is changing during the life, the IQ (intelligence quotient) does not. This measure is defined to have mean of 100 in each age group. So the average IQ e.g. in the age 5 is 100, and the same in the age 50.
What IQ puts you in the top 2 percent? ›
A score of 130 or higher signals a high IQ. Membership in Mensa, the High IQ society, includes people who score in the top 2 percent, which is usually 132 or higher.What is the 99th percentile IQ? ›
If we apply the empirical rule to IQ distribution, we can say that 68% of people have an IQ between 85 and 115; 95% - between 70 and 130; and 99.7% - between 55 and 145.Whats a 99th percentile IQ? ›
Approximately 98–99th percentiles on standardized tests. Terms Highly to Exceptionally Gifted or Very Advanced on IQ tests. IQ scores of about 130 to 140.What is the average IQ of a Phd? ›
Originally Answered: What is the average IQ of PHds? It depends on the field. Generally above 120, similar to law and medicine. For physics and math, some estimates are around 145.What was Albert Einstein's IQ? ›
Smarter than Einstein? Albert Einstein likely never took an IQ test but is estimated to have a 160 IQ—but even that can't stand up to these masterminds.Is IQ 140 gifted? ›
Depending on which test is used, the gifted IQ range is as follows: Mildly gifted: 115 to 129. Moderately gifted: 130 to 144. Highly gifted: 145 to 159.What is the IQ of Mark Zuckerberg? ›
Various sources, however, estimate it at 152 IQ based on biographical data, publications, and achievements. He is regarded as a genius and among the world's most intellectual individuals. A score of 152 is regarded as high, while a score of 100 is considered normal.What was Stephen Hawking's IQ? ›
Similar to Einstein, theoretical physicist Stephen Hawking had an estimated IQ of 160, yet it is unknown if he ever took an IQ test, according to enhancingbrain.com. According to Healthline, about 68% of people have an IQ between 85 and 115. The average IQ score in the U.S. is 98, says Healthline.Who has 400 IQ? ›
|Marilyn vos Savant|
|Born||Marilyn Mach August 11, 1946 St. Louis, Missouri, U.S.|
|Spouse||Robert Jarvik ( m. 1987)|
|Brad Pitt||Hollywood actor||126|
How rare is an IQ of 140? ›
The first genius IQ score was around 140. That's about one in every 250 people.How smart am I if my IQ is 124? ›
According to the WAIS-IV scale, you are a superior intelligent individual with an IQ 124 score. This is substantially above the typical range on all scales. Given that the typical range is 90 to 109, IQ 124 is clearly substantially higher.Is 100 a good IQ? ›
So in most cases, if you receive an IQ score of around 100, then you have what is considered an average IQ. Don't worry—you are in good company. Most people score within one standard deviation of this average.How smart is a 93 IQ? ›
An IQ 93 falls into the average IQ score group, indicating that the individual has average intellect, which is the same as most people. This IQ level is typical, and there is no need to be concerned.What is the lowest IQ ever recorded? ›
The lowest IQ score is 0/200, but nobody in recorded history has officially scored 0. Any result below 75 points is an indicator of some form of mental or cognitive impairment.What IQ do you need to get into Harvard? ›
What IQ do you need to get into Harvard? “Average” in a selective prep school can be ~120. Average IQ at MIT or Harvard is closer to 130. Average SAT score is 1000 (M+V).Does Mensa look good on a resume? ›
A: Joining Mensa is an excellent way to meet and socialize with people of similar intellectual abilities, but it does not belong on a resume, which will be explained later.What is a good IQ score by age? ›
|Age Range||Average IQ Score|
|20 to 24-year-olds||99|
|24 to 34-year-olds||97|
|35 to 44-year-olds||101|
|45 to 54-year-olds||106|
To further simplify it: An IQ of 75 means that an 8-year-old child will function intellectually overall at 75% of the average 8-year-old's intellectual functioning ie, at an average of a 6-year-old level. As he ages, he will commensurately function intellectually as a 12-year-old at age 16 years.How common is an IQ of 122? ›
An IQ 122 score is considered high. Individuals with this score outperform 92.9 percent of their peers in their age group. On a credible IQ test, only around one out of every ten people would score so high.
What 9 year old Mexican girl has a high IQ? ›
Adhara Pérez Sánchez, from Mexico, scored an astonishing 162 on her IQ test, which is believed to be two points higher than Einstein and Hawking, two of the cleverest men who ever lived. Adhara has set her sights on being an astronaut, travelling to space, and even colonising the red planet.What is the average IQ of military officers? ›
Officers scored 121.9, bringing up the average IQ for those who died. Non-commissioned officers scored an average of 106.7.What IQ is considered disabled? ›
have an IQ score below 60; have an IQ score of 60 through 70 and another physical or mental impairment that limits the ability to work; or.At what age is your brain at its peak? ›
They conclude that humans reach their cognitive peak around the age of 35 and begin to decline after the age of 45. And our cognitive abilities today exceed those of our ancestors. “Performance reveals a hump-shaped pattern over the life cycle,” report the authors in Proceedings of the National Academy of Sciences.Is IQ born or developed? ›
Like most aspects of human behavior and cognition, intelligence is a complex trait that is influenced by both genetic and environmental factors.Is your IQ set from birth? ›
IQ tends to remain relatively stable over the lifespan. The key word there is relative. Keep in mind that IQ researchers are interested in explaining differences. Developmentally speaking, an individual's intelligence is not fixed at birth.How rare is an IQ of 130? ›
Just 2.2 percent have an IQ of 130 or greater. What's fascinating is that people who score well on one of the tests tend to score well on them all.What is the strongest predictor of IQ scores? ›
The single strongest predictor of a person's IQ is the IQ of his or her mother. Also interesting: However, once you get beyond the school environment, it's not a very reliable predictor of performance.Is IQ a genetic trait? ›
Researchers have previously shown that a person's IQ is highly influenced by genetic factors, and have even identified certain genes that play a role. They've also shown that performance in school has genetic factors. But it's been unclear whether the same genes that influence IQ also influence grades and test scores.What IQ is considered gifted in Florida? ›
Typically a full scale IQ of 130 or above classifies a student as gifted. However in some school districts ESL/ESOL students who also qualify for Plan B (reduced lunch) are entitled to enter the gifted program with lower IQ scores (e.g. 115-120).
How rare is an IQ of 200? ›
For one thing, no one with an IQ of 200 would ask that question in the first place because the probability of having an IQ >= 200 is 1 in 76,429,666,479 or 1 in 76 billion.How smart is a 96 IQ? ›
IQ 96 indicates that you have a normal sort of thinking capacity that falls into the category of "Average Intelligence" on the IQ scale range chart, which accounts for 51.6 percent of the world's population.What percentile is highly gifted? ›
Those who are profoundly gifted score in the 99.9th percentile on IQ tests and have an exceptionally high level of intellectual prowess. These students score at least three standard deviations above the norm on the bell curve, so they are at the extreme end of the intelligence, or IQ, continuum.What is considered gifted? ›
Giftedness is often defined as an intellectual ability linked to an IQ score of 130 or more. However, not all gifted children excel in an academic area. Sometimes giftedness shows up as a high creative, artistic, musical and/or leadership ability relative to same-age peers.Is 97th percentile gifted? ›
Generally, people consider an IQ of 130 or higher to be gifted. That's in about the 97th percentile.What does an IQ score of 120 mean? ›
An IQ score over 140 indicates that you're a genius or nearly a genius, while 120 - 140 is classed as "very superior intelligence". 110 - 119 is "superior intelligence", while 90 - 109 is "normal or average intelligence".What does 125 IQ mean? ›
People with an IQ between 121 and 130 are called gifted. They constitute 6.7 percent of the population. They possess characteristics that enable them to easily grasp theories and concepts. They may also excel in particular topics such as the arts, mathematics, physics, and so forth.What is the minimum IQ for Mensa? ›
The minimum accepted score on the Stanford–Binet is 132, while for the Cattell it is 148 and 130 in the Wechsler tests (WAIS, WISC). Most IQ tests are designed to yield a mean score of 100 with a standard deviation of 15; the 98th-percentile score under these conditions is 131, assuming a normal distribution.Is 122 a high IQ? ›
A score of 116 or more is considered above average. A score of 130 or higher signals a high IQ. Membership in Mensa, the High IQ society, includes people who score in the top 2 percent, which is usually 132 or higher.Can you increase your IQ? ›
Although science is on the fence about whether you can raise your IQ or not, research does seem to suggest that it's possible to raise your intelligence through certain brain-training activities. Training your memory, executive control, and visuospatial reasoning can help to boost your intelligence levels.
What are the signs of high IQ in adults? ›
Signs of Genius in Adults. The signs of high intellectual power in adults are similar to those in children. They include quick learning, interest in unique topics, and the ability to process information fast, among others.What is the 99.9 percentile IQ? ›
Triple Nine Society.
The average I.Q. of a doctor is approximately 125. Studies have determined that a doctor's I.Q. will normally fall within the 110-130 range, putting them into the 'high average' and 'superior' Wechsler classifications.