Is the IQ test a reliable tool for measuring our intelligence?

The IQ test is an indicator that measures a person’s level of intelligence based on the answers provided to a series of questions that evaluate an individual’s verbal, logical and analytical, mathematical, mnemonic and spatial visualization skills. But is it a reliable tool for assessing a person’s intelligence? According to studies in recent years, this method is actually quite outdated, given that it does not take into account numerous environmental and social factors such as level of education, economic well-being and healthcare, as well as age. On the contrary, the theory of multiple intelligences – the most widespread among psychologists and neuropsychiatrists – maintains that intelligence actually has various dimensions and IQ tests would “capture” only a small portion of it.

How an IQ test is done

Till today does not exist a unique IQ evaluation test, but despite the differences between the many existing tests, almost all of them have some elements in common: in addition to total scoreoffer a score relative to individual parts of the test, which can be referred to the following skills: verbal logic, working memory And visuospatial skills. This way the person who was administered the test can see which skills they are strongest in.

During the administration of the test there is almost always a pre-established number of questions (typically a few dozen), a person who supervises who is doing it and a pre-established time in which you can answer the questions, while in others there is a total maximum time or a precise (and very short!) time depending on the group of problems. There are even some tests that do not have a time limit or supervision, but generally this mode is only valid for measuring high IQ values.

IQ test example

How IQ is calculated: the history of the test

At the beginning of the twentieth century, the French psychologist Alfred Binet and Theodore Simon they wondered how to identify early on the students who most needed help at school level, so they invented the Binet-Simon scale, a test that measured the child’s mental age. However, it was the German psychologist William Louis Stern to coin the term “IQ”, which could be calculated with a simple formula:

IQ = (mental age : biological age) · 100.

For example: a 10-year-old who could solve problems that the average 10-year-old could solve had a score of 100. A 10-year-old who could solve problems that a 12-year-old could solve had a score of 120 ( = 12/10 · 100).

This method was the basis on which he studied David Wechsler to process the first intelligence test for adults (WAIS) in 1939, then also extended to children (WISC).

David Wechsler

The Wechsler test was different from the Binet-Simon test: instead of being based on a quotient related to age, it based the IQ score on the fact that this score follows a particular statistical distribution called Gaussian curveto which an average value of 100 is assigned. According to this distribution, the 68% of the population has a score of between 85 and 115; only 2.2% reach a score of 130 and above (gifted) or below 70. They tend to be considered Bass an IQ lower than 70-75 e high above 130. Therefore, if a person performs better on a test than 90% of the other individuals who took the test, their score will be 115. There is no maximum limit for IQbut higher values ​​become increasingly unlikely.


Furthermore, if in the Binet-Simon test there was only one total score, in the Wechsler scales the scores in each category. The third edition of the test, released in 1997 and still in use today, it is divided into two macro categories which include various types of exercises: verbal (reading comprehension, knowledge of words, ordering of numbers and letters), e ability (arithmetic reasoning, symbol coding, picture completion, Raven matrices, short-term memory, etc.).

The researchers hypothesized that the test score reflected thegeneral intelligence (called “g-factor”), which was mainly based on the three aspects still evaluated today: verbal logic, working memory and visuospatial skills.

How reliable is the IQ test for measuring intelligence

But how reliable is the IQ test in determining how intelligent a person actually is? To date, the scientific community considers it an obsolete tool and therefore not entirely reliable.

For example, during the second half of the twentieth century, scientists noticed that new generations scored much higher on IQ tests than previous generations. This phenomenon, called Flynn effect from the surname of the psychologist who described it, it happened so quickly that researchers understood that IQ certainly could not be attributed solely to evolutionary and hereditary factors as had been believed for decades, but could be attributed to environmental and social factors. Access to other degrees of instruction and to a better one health caretogether with one nutrition adequate and one family present that is able to satisfy the child’s needs are extremely important factors for the development of a certain level of IQ.

IQ test

From the results obtained it was also discovered that intelligence increases during development, it stabilizes between the ages of 20 and 24 and tends to decrease with advancing age. This is also because the Grey matterwhich is involved in the processes of language, attention and short- and long-term memory decreases irremediably at an advanced age.

In short, IQ does not only measure intelligence but is the result of many other factors. We must also take into account that today There is no agreed definition of exactly what “general intelligence” is. (i.e. the g-factor); rather, the so-called is in vogue among psychologists theory of multiple intelligences developed at the end of the 70s by the American psychologist Howard Gardneraccording to which intelligence is a set of different abilities: intrapersonal, interpersonal, linguistic-verbal, logical-mathematical, musical, naturalistic, visual-spatial, corporeal-kinesthetic and philosophical-existential.

We all have one (or more) preponderant intelligences among those described by Gardner: there are those who are better suited to music and interpersonal relationships, those who are better suited to writing and art, or those who instead have philosophical and interpersonal skills. high. According to this theory, therefore, IQ test is useful for evaluate verbal and logical performance of an individual, but it is reductive to think that intelligence can be deduced only from this. For many years, Gardner’s theory has been the most accredited by psychologists because it takes into consideration the fact that human beings have very different abilities that characterize them, and therefore intelligences that stand out more than others.

Who was the person with the highest IQ in history?

When talking about high IQs we immediately tend to think of personalities like Albert Einstein (160) or Nikola Tesla (180), but these are estimates made by scientists without actual measurement. Yet, the person with the highest measured IQ ever is not famous: he was William Sidisa child prodigy from New York born at the end of the nineteenth century, with a score of 254. Eccentric and with extraordinary mathematical skills, he was admitted to Harvard University at the age of 11 and could speak 25 languages ​​fluently.

William Sidis

Currently, the living man with the highest IQ is Terence Taomathematician of Chinese and American origins with a score of 230, while the woman with the highest IQ is the American essayist Marilyn Von Savant (228).