Measuring and weighing ourselves are relatively everyday habits. The scale and the tape measure give us an unquestionable piece of information, we like it more or less. Almost 80 kilos, 1.65 high and it’s over. It is not questioned because there is nothing to question (unless the balance is badly balanced). However, when it comes to estimating intelligence, things change, because not everyone agrees that a number – the score obtained in the tests that measure the IQ – is the fairest criterion. or valid to determine our mental skills, since they consider that they go much further than quickly identifying the drawing that completes a series, for example.

In fact, this evidence continues to be debated and highly questioned. A common criticism is that only assess a limited set of intellectual abilitiesespecially how quickly each person solves a series of insignificant problems by making as few mistakes as possible, rather than measuring whether they are able to solve significant problems by making as many productive mistakes as necessary, regardless of how long it takes. Other critics argue that these tests discriminate against minorities, being made according to the western concept of intelligence.

Its defenders assure, however, that These statements do not correspond to scientific reality. «It is true that measuring reaction times is a way of knowing the cognitive or attentional efficiency of a person, but the tests that measure, rather, are intelligence factors of increasing difficulty, which allow identifying the intellectual capacity of the person », Explains José Antonio Portellano, neuropsychologist and doctor in Psychology from the Complutense University of Madrid. “What’s more, there are culture-free intelligence tests, which measure the intelligence potential in any person, regardless of their socioeconomic, educational or cultural level. Likewise, these tests have to be adapted to each country, with different scales. For example, the most famous intelligence test in the world, the Wechsler scales, is of American origin, but it is adapted to the population of many countries. Spain, itself, has its own versions of this test, “he says.

“These tests have been carried out for more than a century, if they had not been valid they would have ceased to be used with the outbreak of the great wars”
Jose Antonio PortEllano

Notably the results obtained in the intelligence tests are not something immutable and that there are circumstances that may influence the result, such as the individual’s state of mind or health when performing it, or even their prior knowledge of these tests. Even so, they are considered a good working tool, as long as they are rigorously designed by a team of qualified professionals.

«These tests have been carried out for more than a century, if they had not been valid they would have ceased to be used with the outbreak of the great wars. That they have been maintained is an empirical demonstration of their usefulness. The skepticism around them responds to a lack of knowledge about how they work. It is not the same to invent a ten-question test and post it on the internet to serve as a hobby, which only damages the image of these tests, than to design a test that has passed and meets the filters and quality requirements demanded by professional scientific committees » , declares Portellano.

Intelligence grows

The first author to develop a method for measuring intelligence was Alfred Binet, although the one who proposed the concept of IQ was William Stern. This unit of measure was initially obtained dividing the mental age by the chronological age of the person and multiplying the result by 100. If the mental age was higher than the chronological age, the individual’s IQ was above the average, but if it was lower, their intelligence was deficient. Most people get a result around 100 because, generally, our mental age is the same or similar to our chronological age. From the Stanford-Binet test, others appeared, such as the Raven Progressive Matrices test or the Wechsler scales, which are the most used today.

Each of them is different. Some include words or numbers and require specific cultural knowledge (such as vocabulary) and others, on the other hand, contain only shapes and designs that only require simple universal knowledge, how to distinguish the difference between a lot and a little or between one pattern and another. «There is no test that measures all intelligence factors 100%, but it does calculate general intelligence (known as ‘G factor’), which is what reflects our ability to solve problems logically, regardless of our training cultural, so they are applicable to any population group, ”explains Portellano.

The specialist also highlights that the brain is an organ endowed with great plasticity and that intelligence can increase or decrease depending on how we stimulate it. «Babies of mothers who suffer from malnutrition during pregnancy tend to have a lower IQ, while those who have greater access to education, culture and healthy eating from childhood, can develop a higher IQ ». And he adds a simile: «Those who do sports every day are in better physical shape than those who spend many hours sitting in front of the television. In the same way, those who practice mental activity more frequently (reading, learning languages, playing an instrument …), reinforce the brain circuits and maintain their intelligence better ». Portellano also tries to demystify that, with age, our IQ decreases markedly, because it is already known that, “with proper practice, the effects of Alzheimer’s can be slowed down.”

Furthermore, it points out that the expression of intelligence is transformed. «Before it was necessary to have a map and understand it to get to a certain place by car and now not because we have geolocation programs such as GPS. Nor do we need to memorize many things, because in smart devices with internet we have a lot of information immediately. These modes of intelligence are not atrophied, they are simply transformed because new ones emerge, such as video games. In fact, There is evidence that Humanity, as a whole, is increasingly intelligent, because there is less and less malnutrition, better health and more global access to culture, is what is known as the ‘Flynn Effect’.

Sample questions from one of these tests
Elements of the Raven IQ Test

These are some of the exercises contained in this test, focused on measuring general intelligence. It is only a sample to test your brain, it will not help you to know your IQ.

- How is IQ measured?
- How is IQ measured?
- How is IQ measured?

Types of IQ

Null cognitive ability (0-4)

The person cannot read, write or speak. Less than 0.000001% of the population has such an IQ.

Profound cognitive disability (5-19)

These individuals usually present with an identified neurological disease and considerable alterations in sensory-motor functioning.

Severe cognitive disability (20-34)

They can learn basic speaking and self-care skills.

Moderate cognitive disability (35-54)

In addition to the above, they can learn to move alone in familiar places and, for the most part, are capable of unskilled or semi-skilled jobs with supervision.

Mild cognitive disability (55-69)

It is equivalent to approximately 87% of people affected by this disorder. They have minimal autonomy, but may need guidance and assistance in certain situations.

Borderline intelligence (70-84)

1 in 9 people occupy this range. It is responsible for some children failing in school.

Below average (85-99)

Their intelligence is slightly below average, but the difference is almost imperceptible. 11% of the world’s population is in this status.

Mean IQ established (100)

It is the range that encompasses most of the population. It is the midpoint on which the entire scale is based.

Above average (101-119)

3 out of 10 people are in this range, which is not too different from the average.

Brilliant Intelligence (120-129)

They present an intelligence superior to the others. The average for most of the people with the highest intellectual performance careers in the Western world is around 125 IQ points.

Intellectual giftedness (130-139)

This group is also made up of many people with high positions, such as governments and businessmen, but mainly elite scientists.

Intellectual genius (140-154)

Geniuses are those who have an IQ equal to or greater than 140 (generally), and represent 0.1% (1 in 1000) of the population.

Higher intelligence (155-174)

It has a rarity of one in three thousand five hundred people. Their way of thinking is radically different and misunderstood and, as a consequence, they often suffer from problems such as poor academic or work performance syndrome, emotional problems or personality disorders.

Exceptional Intelligence (175-184)

Only one in 700 thousand people in the world reaches such intelligence. The person can read before reaching the age of three.

Deep Intelligence (185-201)

It occurs in one person in every 18 million, approximately 0.00000005% of individuals around the world have such a quotient.

Intelligence greater than 201

Figures greater than this number are unlikely, since the rarity is one in eight billion people, and humanity barely exceeds seven billion.