IQ, or intelligence quotient, is a measure of your ability to reason and solve problems. It reflects how well you did on a specific test compared to other people of your age group.
While tests may vary, the average IQ on many tests is 100, and 68% of scores lie between 85 and 115.
A low IQ score is anything 70 and below. A low score and other indicators might suggest that a person has an intellectual disability. Anything over 140 is considered a genius IQ score. For context, while there is no evidence that he was ever tested, is it estimated that Albert Einstein had a score of around 160.
While IQ can predict things such as academic success, experts caution that it is not necessarily a guarantee of life success. Sometimes people with very high IQs do not fare well in life, while those with average IQs may thrive.
What Does IQ Mean?
IQ tests measure mental ability and provide a score to show how a person's results compare to others in their age group. IQ encompasses a range of mental abilities, including verbal reasoning, visual abilities, spatial awareness, processing speed, and pattern recognition.
Average IQ Scores
The measurement of intelligence has long been a hot topic in psychology and education—and a controversial one. Intelligence tests are one of the most popular types of psychological tests in use today. Ever since the first IQ tests emerged, attempts to classify IQ have followed.
In order to understand what an average IQ score is and what it means, it is essential to first understand how IQ is measured. While different test publishers utilize different scoring systems, for many modernIQ teststhe average (ormean) score is set at 100with astandard deviationof 15 so that scores conform to a normal distribution curve.
- On many tests, a score of 100 is considered the average IQ.
- Sixty-eight percent of scores fall within one standard deviation of the mean (that is, between 85 and 115). That means that nearly 70% of all people score within plus or minus 15 points of the average score.
- Ninety-five percent of scores fall within two standard deviations (between 70 and 130). Outliers beyond those points represent only a small portion of the population, which means that only a small percentage of people have a very low IQ (below 70) or a very high IQ (above 130).
- Scores below 70 may represent the presence of some sort of developmental or learning disability while scores over 130 may indicate giftedness.
How IQ Is Calculated
Historically, IQ tests have been scored in one of two ways. In the first method, a person's mental age was divided by their chronological age and then multiplied by 100. The other methods involve comparing scores against the scores of others in the individual's same age group.
In this method, psychometricians utilize a process known asstandardizationto make it possible to compare and interpret the meaning ofIQ scores. This process is accomplished by administering the test to arepresentative sampleand using these scores to establish standards, usually referred to as norms, by which all individual scores can be compared.
Because the median score is 100, experts can quickly assess individual test scores against the median to determine where these scores fall on the normal distribution. This means 50% of the scores fall above and below the median. In the case of IQ scores, both the mean and median score is 100. Classification systems can vary from one publisher to the next although many do tend to follow a fairly similar rating system.
For example, on The Wechsler Adult Intelligence Scale and the Stanford-Binet test, scores that fall between 90 and 109 are considered average IQ scores. On these same tests, scores that fall between 110 and 119 are considered high average IQ scores. Scores between 80 and 89 are classified as low average.
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 to Find the Mean, Median, and Mode
How Intelligence Is Measured
Intelligence tests are designed to measurecrystallized and fluid intelligence. Crystallized intelligence involves your knowledge and skills you have acquired throughout your life whilefluid intelligenceis your ability to reason, problem-solve and make sense of abstract information.
Fluid intelligence is considered independent of learning and tends to decline in later adulthood. Crystallized intelligence, on the other hand, is directly related to learning and experience and tends to increase as people grow older.
IQ tests are administered by licensed psychologists. There are different kinds of intelligence tests, but many involve a series of subtests that are designed to measure mathematical abilities, language skills, memory, reasoning skills, and information-processing speed.
Scores on these subtests are then combined to form an overall IQ score. A few of the most common IQ tests in use today include:
- The Wechsler Adult Intelligence Scale for Adults
- The Wechsler Intelligence Scale for Children
- The Stanford-Binet Intelligence Scales
- The Kaufman Assessment Battery for Children
- The Cognitive Assessment System
- The Differential Ability Scales
- The Woodcock-Johnson Tests of Cognitive Abilities
It is important to note that while people often talk about average, low and genius IQs, there is no single IQ test.
Many different tests are in use today including the afore-mentioned Stanford-Binet and the Wechsler Adult Intelligence Scale, as well as the Woodcock-Johnson Tests of Cognitive Abilities. Each individual test isdifferent in terms of exactly what is being measured, how it is scored, and how these scores are interpreted.
Controversies Over IQ
Ever since the inception of the very first tests of intelligence, both academics and armchair psychologists have debated differences in intelligence, including possible connections between IQ and race.
In addition to connections between race and IQ, people have also attempted to connect IQ disparities to other factors such as sex differences and nationality.
One important factor to also note is that overall, IQ scores have been rising worldwide, a phenomenon known as the Flynn effect.
Race and IQ Scores
During the 1920s, the US Army utilized IQ testing on recruits and found that different populations showed group differences in average IQ scores. Such findings helped fuel the eugenics movement and those who supported racial segregation.
The 1994 book The Bell Curve rekindled the argument and controversy, as the book promoted the notion that racial group differences in average IQ scores were largely the result of genetics. Critics suggest that such group differences are more accurately a product of environmental variables.
Such arguments over race and IQ are a reflection of the age-old nature versus nurture debate. Are certain traits, characteristics, and abilities more heavily influenced by genetics or by environmental causes? Those who believe that race is a determinate of IQ are taking the side of nature, suggesting that heritability is the primary determinant of IQ.
However, research has found that while genetics play a role in determining intelligence, environmental factors also play an important role. Some factors linked to group differences in average IQ scores include education, health and nutrition, socioeconomic status, testing bias, and minority status.
In response, the American Psychological Association formed a special task force led by psychologist Ulric Neisser to investigate the claims made by the book. They found no direct evidence to support genetic explanations for test score differences between Blacks and Whites. Instead, they stated that there are no known explanations for such differences.
Discrimination and systemic bias may also play a role in these differences, including educational and healthcare disparities. It is also important to consider biases that may be inherent in the tests themselves.
Nationality Differences in Average IQ Scores
Studies of national cognitive ability suggest that there are differences in IQ scores among different nations. Such studies remain limited, but some explorations of this topic have been conducted by creating estimates of average IQ for different nations. Such differences may be largely linked to environmental influences such as socioeconomic factors, literacy rates, educational rates, and life expectancy.
According to research conducted by Richard Lynn and Tatu Vanhanen, Hong Kong had the highest average IQ at 108 while Equatorial Guinea had the lowest at 59. Average group IQs of some other countries included the United States at 98, the United Kingdom at 100, and Italy at 102.
Sex Differences in Average IQ Scores
Over the years, some researchers have argued that either males or females held an advantage in terms of IQ while others have argued that there are no significant differences between men and women.
One study found that while there was no average difference in IQ scores between men and women, there tended to be more variability in IQ scores among men.
Research has found that there are slight differences in the performance of verbal and spatial tasks, with women performing better on some verbal tasks and men performing better on some spatial ability tasks. However, researchers believe that this disparity is only partially due to biological differences and is also influenced by culture, experiences, and education.
What Does It Mean to Have an Average IQ?
While some limited generalizations can be made in relation to your average IQ score, keep the following in mind:
- It means you have average reasoning and problem-solving skills.Your IQ score might be a good general indicator of your reasoning andproblem-solving abilities, but many psychologists suggest that these tests don't tell the whole story.
- An average IQ score might not tell the whole story about what you are capable of.A few things they don't measure are practical skills and talents. You might have an average IQ score, but you might also be a great musician, a creative artist, an incredible singer or a mechanical whiz. Psychologist Howard Gardner developed a theory ofmultiple intelligencesdesigned to address this perceived shortcoming in popular conceptions of IQ.
- IQ scores are not necessarily set in stone.Researchers have also found that IQ scores can change over time. One study looked at the IQ's of teenage subjects during early adolescence and then again four years later. The results revealed that scores varied as much as 20 points over that four-year period.
- Some experts suggest that EQ might matter even more than IQ.IQ tests also fail to address things like how curious you are about the world around you and how good you are at understanding and managing emotions. Some experts, including writer Daniel Goleman, suggest thatemotional intelligence(often referred to as EQ) mighteven be more important than IQ. And researchers have found that while having a high IQ can indeed give people anedge in many areas of life, it is certainlyno guarantee of life success.
A Word From Verywell
Don't stress out if you're not a "genius"—the vast majority of people aren't geniuses either. Instead, most people are somewhere within a 15-point range of the average IQ score.
Just as having a high IQ doesn't ensure success, having an average orlow IQdoesn't ensure failure or mediocrity. Even if you have what is considered a low IQ, you may be smart in many other ways and have many other talents and abilities that aren't reflected on a single test. Other factors such as hard work,resilience, perseverance, and overallattitudeare important pieces of the puzzle.
Are High IQ People More Successful?