What is intelligence? It's your ability to reason, solve problems, learn quickly, and grasp complex ideas—not just book knowledge or test-taking skill. Discover what intelligence really means.
Dr. Russell T. WarneChief Scientist
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Intelligence is one of those concepts that everyone seems to understand intuitively, yet becomes surprisingly difficult to define precisely. We all know people we consider "smart," but what exactly makes someone intelligent? Is it their ability to solve math problems quickly? Their extensive vocabulary? Their knack for understanding complex ideas? The answer, according to psychological science, is all of these things and more.
Defining Intelligence
In 1994, over 50 leading intelligence researchers signeda consensus statement that defined intelligence as "a very general mental capability that, among other things, involves the ability to reason, plan, solve problems, think abstractly, comprehend complex ideas, learn quickly, and learn from experience."
Notice what the definition says about what intelligence is not. Intelligence is "not merely book learning, a narrow academic skill, or test-taking smarts." Rather, it's a broader capacity for understanding the world, which is what the researchers describe as "catching on," "making sense" of things, or "figuring out" what to do. This helps explain why intelligent people tend to perform well not just in school, but across many different areas of life.
Intelligence in Everyday Life
The practical importance of intelligence becomes clear when we look at real-world outcomes. People with higher intelligence tend to learn new skills more quickly, adapt to changing circumstances more easily, and solve novel problems more effectively.
Research shows that intelligence predictsperformance in school, workplacesuccess, healthoutcomes, and evenlongevity. There are always exceptions to these patterns; not every intelligent person succeeds academically, and success has multiple causes. But on average, the relationship is clear and consistent.
What Intelligence Is Not
Intelligence is not the same as knowledge or education, though these concepts are related. A person can be highly intelligent but poorly educated, just as someone can be well-educated but of average intelligence. Education provides the content: the facts, skills, and information we learn. Intelligence provides the capacity to acquire and use that content effectively. However, given the same educational experience, more intelligent people learn more quickly and retain more knowledge than their less intelligent classmates.
Intelligence is also distinct from wisdom and creativity. Wisdom includes a cultural component that is often absent from definitions of intelligence found in psychology. Behaviors that may be considered wise in one culture may not be wise in another, and these differences have more to do with context, traditions, and group history than individual cognition. The relationship between creativity and intelligence has been the topic of scientific controversy for over 50 years. The two variables are positively correlated, but it is not clear how or why. More intelligent people are more creative, but measuring creative outputs are, by definition, unusual and somewhat rare. That makes creativity difficult to study. Psychological tests to measure creativity in the general population have been developed, but the most popular creativity tests have inadequacies that have not been addressed.
Finally, intelligence is neither fixed at birth nor entirely malleable. While it has a strong genetic component and tends to be quite stable throughout most of the lifespan, environmental factors matter. Good schooling, intellectual stimulation, and avoiding environmental toxins (like lead poisoning) all influence cognitive development.
How Is Intelligence Measured?
Intelligence is typically measured using IQ tests, which are carefully designed assessments that sample various cognitive abilities. It is surprising to some people that there is no single type of question that appears on all IQ tests. What matters is that the tasks require thinking, judgment, and reasoning.
Some tests measure verbal abilities through vocabulary or reasoning tasks. Others assess spatial reasoning by asking test-takers to manipulate mental images. Still others measure processing speed, working memory, or pattern identification. The scores are expressed as IQ scores, with an average of 100 and a standard deviation of 15. About two-thirds of people score between 85 and 115.
For a more in-depth discussion on what these tests measure, watch:
If you're curious about your own intelligence, taking a professionally developed IQ test can provide valuable insights. However, be selective. The internet is flooded with so-called IQ tests created by amateurs with no training in psychological assessment.
The Reasoning and Intelligence Online Test is the first online IQ test that meets professional standards for psychological assessment. It underwent the same rigorous development process as traditional in-person IQ tests used by psychologists, including expert review, the first ever proper US-based online norm sample, and meets the standards for educational and psychological testing established by the American Psychological Association, American Educational Research Association, and the National Council on Measurement in Education.
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Want to know your IQ? Try the first ever professional online IQ test.
