Have you ever heard someone bragging about being a genius and talking about his IQ of 145? On some IQ scales, a score of 145 is genius level, but on other scales, a score of 145 is just higher than average.

Ever since the ancient Greeks, people have been interested in quantifying their intelligence and the intelligence of others. However, modern intelligence tests are a more recent invention. We can thank the research of 20th-century psychologist Alfred Binet for the modern intelligence quotient scale. Without him, we would not know the IQ test as it looks today.

What Is the Intelligence Quotient Scale?

IQ may not mean what you think it means. Although most people use it to define a crystalline or innate and unchanging form of intelligence, the IQ scale is really more of a comparison. IQ is actually a measure of how people score on a standardized logic test compared with other people of their age.

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On the fifth edition of the Stanford-Binet Scale, scores range from 40 on the low end to 160 on the high end. Individuals who score between 145 and 160 are considered to be very gifted or highly advanced. Individuals who score between 90 and 109 are considered average, and levels of impairment begin below 79. Other scales that go up to and beyond 200 are more prevalent on the internet and should not be applied as a standard for genuine psychological testing.

What Is an IQ Test?

Put simply, an IQ test is a standardized test designed to measure human intelligence in comparison with others. The first form of the modern IQ test was developed by French psychologist Alfred Binet. His research began in the 1900s when the French government asked him to develop a way to measure the intelligence of French schoolchildren. The purpose of this testing was to identify students who were struggling with their schoolwork so schools and teachers could give them extra assistance.

The original test that Binet developed measured psychological and neurological skills such as problem solving and memory. However, Binet discovered that this first test was not the best measure of intelligence. Instead, it seemed to measure age because scores were gradually increased according to each child’s grade level.

Rather than going back to the drawing board, Binet understood that he had discovered something valuable. The test he had developed could be used to create age-based benchmarks. Teachers and psychologists could then use these benchmarks to compare students with their peers. Ultimately, Binet recognized the limitations of this test. Ironically, he was afraid of the very thing that IQ testing is commonly used for today: to suggest an individual’s permanent intelligence.

What Is a Normal IQ Range?

In the early 1900s, personal pedigrees and intelligence testing became the new craze in the United States. Capitalizing on America’s new-found interest, psychologist Lewis Terman adapted Binet’s test to a set of American subjects. Terman named his test the Stanford-Binet Intelligence Scale, and it remains in wide use today, from mockup games claiming to test intelligence on the internet to schools testing students for placement in gifted classes.

The Stanford-Binet Intelligence Scale uses a simple formula to calculate a participant’s IQ: mental age divided by chronological age, the product of which is then multiplied by 100. On the Stanford-Binet Intelligence Scale, scores between 90 and 109 are considered average. The scale scores can be read as follows:

  • 145-160: highly advanced or gifted
  • 130-144: very advanced or gifted
  • 120-129: superior
  • 110-119: high average
  • 90-109: average
  • 80-89: low average
  • 70-79: borderline impairment
  • 55-69: mild impairment
  • 40-54: moderate impairment

Beyond bragging rights or joining an elite club, there are very few legitimate reasons a functioning adult should need to take an intelligence test. The most useful applications of intelligence testing lie in educational and neurological research. People with low IQs often live successful lives, and having a high IQ is not necessarily an indicator of much more than stellar test-taking skills.

However, if you’re taking an intelligence test with the dream of making yourself smarter, what you should do is endeavor to improve your knowledge instead. Just like Binet’s fear, intelligence is not a fixed characteristic of an individual. Intelligence is fluid. People can learn and improve themselves by applying cognitive psychology to their studies. If you want to feel smarter and learn more, a more fruitful tactic would be to find out what kind of learner you are.

How to Prepare for an IQ Test

Contrary to popular belief, you cannot prepare for most IQ tests. However, if you are taking a test that is similar to an IQ test, like the LSAT, SAT or GRE, you can prepare by practicing test problems and reviewing test-prep booklets.

Legitimate IQ tests are only administered in a few kinds of places. Some schools give intelligence tests as a way to measure students for giftedness or diagnose them with learning disabilities. In these cases, a school counselor or other licensed school psychologist will administer the test.

Besides educational and mental health establishments, some registered testing centers administer a form of IQ test. Mensa also administers its own test, which is an analog for IQ testing.

Other IQ Tests

In the 1950s, David Wechsler developed his own IQ test, the Wechsler Adult Intelligence Scale. Unlike the Stanford-Binet Intelligence Scale, the Wechsler Adult Intelligence Scale offered two versions for application in children, the Wechsler Preschool and Primary Scale of Intelligence and the Wechsler Intelligence Scale for Children.

Like the Stanford-Binet Intelligence Scale, the Wechsler Adult Intelligence Scale is still used today but with modifications and additional development in keeping with new understandings of neurology and psychology. The Wechsler Adult Intelligence Scale now goes by the acronym WAIS-IV.

The WAIS-IV breaks intelligence down into four areas: processing speed, working memory, perceptual reasoning and verbal comprehension. WAIS-IV test results include two separate scores, a General Ability Index and a Full-Scale IQ. Because of its various sections, the WAIS-IV has been successfully applied in identifying learning disabilities in struggling students.

The IQ Test’s Controversial Past

Although taking a test to discover how smart you are seems innocuous enough, intelligence testing has a very controversial past. One of the darkest spots in its history involves eugenics. Henry Herbert Goddard, an American eugenicist in the early 1900s, was a major proponent of intelligence testing and used his influence to encourage institutions across the U.S. to begin using the Binet-Simon IQ scale. Adoption was widespread by 1914, reaching into courts, schools and immigration centers, affecting the daily lives of many Americans at that time.

Goddard’s purpose in spreading the word about intelligence testing was to eliminate people from the population whom he considered “undesirable.” Through the modern lens, this is obviously discriminatory and dangerous to the lives and livelihoods of anyone people like Goddard believed to be inferior.

Goddard called those who did not perform well on intelligence tests “feeble minded,” and he pushed for initiatives that would institutionalize or sterilize these people. You may be thinking that he couldn’t have succeeded, right? Unfortunately, such policies did take effect in the U.S., leading to the forced sterilization of more than 64,000 people.

What should we take away from this historical lesson? The concept of intelligence testing is far from perfect. A human being’s worth cannot be reduced to a simple numerical scale. However, intelligence testing can still be useful. Both on the low end and the high end, it can give teachers valuable information that will let them help their students learn.

Measures of intelligence are also valuable for understanding the influence of outside factors on school performance. For example, research has revealed that a traumatic home life can temporarily decrease students' measurable IQ, leading them to do poorly on schoolwork despite preparation or study habits. This discovery is a major breakthrough for education because it reinforces the idea that schools should pay attention to all of a student’s needs, not just the academic ones.

Multiple Intelligences and Learning Styles

If you were the bored kid who stared out the window or the one who couldn’t sit still in class, you might have been led to believe that you weren’t as smart as your more studious peers. While it’s easy to subscribe to that kind of negative thinking, it’s more likely true that you had not yet discovered your individual learning style.

Newer research in the field of educational psychology has found that there’s not just one but eight different learning styles. Figuring out your personal learning style will help you understand how you process and retain information best. If that sounds like a lot of useless psychological nonsense, hold on. Determining your learning style has many real-life applications, even if you aren’t in school anymore. If you understand your learning style, you will be able to use it to your advantage. You can improve your performance at work, get more done on your to-do list and learn new skills that could help you follow your passion.

What Does Multiple Intelligences Mean?

The phrase “multiple intelligences” comes from the research of Harvard psychologist Dr. Howard Gardner. Gardner’s research indicated that everyone was smart but not always in the same way. So, he outlined eight key areas of intelligence:

Verbal-linguistic intelligence translates into an ease with speaking or writing. Someone with this type of intelligence might have great success as a public speaker or writer.

Musical intelligence grants sensitivity to music. Someone with this type of intelligence would make a great musician.

Logic-mathematical intelligence involves complex reasoning skills and the ability to understand abstract concepts. Computer scientists and mathematicians would greatly benefit from this type of intelligence.

Spatial intelligence allows people to render, build or otherwise create things they have seen in their mind’s eye. General contractors and architects use spatial intelligence every day.

Kinesthetic intelligence relates to an ease in using your body to convey ideas and solve problems. Kinesthetic intelligence would benefit actors, models and dancers.

Interpersonal intelligence helps people work well with others. Many successful psychologists and teachers score high in the area of interpersonal intelligence.

Intrapersonal intelligence is the ability to understand yourself. Creators like writers and artists often use intrapersonal intelligence to understand and communicate their emotions to make relatable, unforgettable work.

Naturalistic intelligence is related to understanding the natural world. Ecologists, zookeepers and forest rangers all use naturalistic intelligence to benefit conservation efforts.

If you’re curious about your own type of intelligence, do a search online for books and tests. Gleaning a basic understanding of your personal learning style is much simpler than finding your IQ. For this reason, tests online and questionnaires in books can be accurate and beneficial. Use the results to plan your future study habits, figure out new skills to learn or consider a career change to a job that harnesses your skills and passion.

About the Author

Rebecca Renner is a teacher and college professor from Florida. She loves teaching about literature, and she writes about books for Book Riot, Real Simple, Electric Literature and more.