What is an IQ and how is it determined?
April 13, by Marissa Edinger

The Intelligence Quotient, more commonly known as an IQ, is a number associated with a person’s perceived cognitive abilities as compared to the general population. Generally speaking, an IQ test (like this one inspired from Raven’s matrices) is designed to measure an individual’s ability to understand concepts and solve problems. IQ tests require participants to use deductive reasoning and problem-solving skills, perceive relationships, and find, store, and recall information.

A reference tool for the evaluation of intellectual potential in 2018

Here is a free IQ test consisting in 40 questions of increasing difficulty level. The candidate must choose from a range of symbols to find the one which completes the set. The challenge is to grasp the relevance of the symbols without context and to understand the relationship between them.

Start a Free IQ test now

Disclaimer: this IQ test is particularly challenging because it assesses the top 25% of the cognitive capacity range. Don't give up!

However, these tests assess general intellectual skills and abilities, requiring the participant to utilize only a few sets of human knowledge realms. Other useful proficiencies, such as social, adaptive, and emotional skills, are not addressed in these types of tests, making the tests indicative of a more logic-based, general intelligence.

Categories measured by IQ tests

Howard Gardner, an American developmental psychologist, broken down intelligence into 9 categories in a book called Frames of Mind: The Theory of Multiple Intelligences. However, IQ tests typically measure general intelligence in only one to four basic categories of ability:

  1. Spatial – the ability to visualize manipulation of shapes
  2. Mathematical – the ability to use logic to solve problems
  3. Language – recognizing relationships between letters and words
  4. Memory – the ability to recall things presented orally or visually

IQ tests are all standardized, meaning the scores are representative of a certain population. This representation follows a normal distribution, or a ’bell curve’, where most people score near the middle. Using a standardization process allows those who define high, medium, and low score definitions to identify norms and standards to use when comparing people’s scores. Typically, 100 is used as the median score. In short, this means that if you exceed 100, you have an above-average intelligence. A lower score indicates that, in a certain extent, you are less intelligent than the average.

The majority of test creators agree that a score of the median plus or minus 10 to 15 (85 to 115) is indicative of ‘average’ intelligence. Any score below a 70 is considered to be a low IQ, while a score above 140 is considered to representative of highly exceptional intelligence.

Modern tests consider age (and appropriately so) when determining a score, meaning a person is graded relative to the population of his/her developmental level. Children, for example, especially benefit from this.

Interpreting IQ test scores

The following list breaks down the generally-accepted labels associated with IQ scores for the society. However, is important to recall that these tests are only one measure of intelligence and shouldn’t be used as an all-encompassing personal label.

  • More than 140 – Genius or close to genius
  • Between 120 – 140 – Very superior intelligence
  • Between 110 – 119 – Superior intelligence
  • Between 90 – 109 – Normal or average intelligence
  • Between 80 – 89 – Dullness
  • Between 70 – 79 – Borderline deficiency
  • Below 70 – Definite feeble-mindedness

IQ tests do not test the quantity of a person’s knowledge. Because of this, studying and learning new information will not necessarily increase a person’s IQ score. However, consistently dedicating time to learning is like an exercise for the brain, which could potentially assist a person in developing his/her cognitive skills. The relationship between learning and mental abilities is still unknown ground in the scientific community. However, intellectual ability seems to be more genetic as opposed to being influenced solely by environmental factors.

So the popular question remains: can a person increase his/her IQ score? The evidence for and agains is mixed. Some studies have shown that children who receive greater nurturing and a healthier diet as babies develop stronger intellectual abilities. Similarly, children who are more strongly intellectually stimulated at young ages have been shown to have boosted IQ scores in elementary school, though the increase is not guaranteed permanently. Adult scores have been shown not to change significantly over time, but keeping oneself in an intellectually stimulating atmosphere can keep cognitive abilities boosted, much like regular exercise keeps a person ‘in shape’.

Data shows that IQ scores are relatively stable, regardless of the education that a person acquires. But this does not mean that a person cannot increase other areas of their intelligence.

IQ tests fail to measure many crucial areas of intellectual ability, and relying solely on this test to measure a person’s potential would be an error. While tests are accurate predictors of academic and workplace success, there are few real-world situations where creativity, wisdom, and communication are not important for success, as well.