How is intelligence relative?

The brain: what is intelligence?

IQ tests are designed to help you discover talent. Whether in the application process or in school classes - astute thinking is an indication of good performance. But researchers don't even agree on how to define our intelligence

Actually, the parents always thought their son was a perfectly normal child. When Max *, now 14, speaks his first words at the age of seven months, they don't think much of it. Most children do not begin to do this for about a year. But the couple from Cologne put up with the fact that Max “is just a little faster”.

However, the family “has nowhere to go without attracting attention,” recalls the mother. When she wants to buy shoes for the one-year-old, the saleswoman asks whether the boy, who seems to be of the crawling age, can't get by with socks. “I can run,” replies Max. “I need shoes.” The perplexed woman then thinks the linguistically gifted toddler is short.

But the real problems only arise when Max is about to start school. “I'm not going there,” he says after the first day: The teacher corresponds too closely to “the cliché of a primary school teacher”. The parents then send him to a Montessori school, where the grades are taught in a joint class.

On the advice of a teacher, they have the boy tested by the child psychologist. The result: Max has an above-average IQ of 142.

The difficulties that this brings with it soon become apparent: At this school too, Max feels underchallenged and cannot get along with the teacher.

In 3rd grade he complained of severe abdominal pain - psychosomatic complaints, it turns out, caused by problems at school. The parents let their son skip a class and go to high school directly. The pain disappears promptly.

Max is one of those children with extraordinary intellectual gifts. Some of the intellectual early starters can already read before their third birthday, amaze with clever questions or already talk like adults in kindergarten.

Some exceptional talents compose their first operas in elementary school or complete their university studies as teenagers - such as Balamurali Ambati, a son of Indian immigrants who graduated from New York at the age of 13 and who became the youngest doctor of medicine in 1995 at the age of 17.

Parents often only find out about their child's special talent through an IQ test. Such thought tests usually consist of several subtasks and are designed so that the average result is 100 points.

The majority of all those tested - around two thirds - scored between 85 and 115 points. Only two percent achieve 130 points or more: Above this relatively arbitrarily set limit, psychologists speak of giftedness. Only four out of 1000 children, like Max, have an IQ of over 140.

IQ tests not only help child and adolescent psychologists to recognize talents at an early stage and thereby enable them to be promoted. Even adults occasionally have to measure their intellectual strength against such tasks: in Germany, for example, during the aptitude test for the Bundeswehr, in the selection process of some universities or when applying for coveted jobs.

IQ test in the USA is a matter of life and death

In the USA, intelligence tests can even determine the survival of the test subjects: there, felons sentenced to death may not be executed if they have an IQ of 70 or less - they are then considered to be mentally retarded and thus limited culpability.

But what such scores actually say about intelligence is controversial: After all, scientists still have problems explaining this property at all.

Intelligence (from Latin intellegere = to understand) is often viewed in a simplistic way as the ability of the mind to recognize connections and solve problems. But there is no single, universal definition.

When, around 1986, the US psychologists Robert Sternberg and Douglas Detterman asked two dozen experts to describe the subject of their research, two dozen different definitions emerged.

In addition, the meaning of intelligence differs from culture to culture: For example, a characteristic often mentioned in Western countries, the high speed of thinking, is considered unwise in other cultures. And in Africa, for example, the Luo, a tribe in Kenya, understand intelligence not only as a relatively narrowly defined intellectual ability, but also as qualities such as respect, a sense of responsibility and consideration.

There are similarly many opinions on IQ. The quotient divides the research community: some see it as a reliable indicator of a person's intellectual potential, others are suspicious of the presumed mental standard or even reject it completely - also because it constitutes discrimination fear of the less gifted according to the IQ test.

A lawyer revolutionizes intelligence research

The dispute over the measurement of the power of the mind has its origin more than 100 years ago when the Frenchman Alfred Binet invented the first modern intelligence test. The lawyer had come to intelligence research through the observation of his two daughters. First, Binet tried to determine the talent of students based on the circumference of their skulls. But he soon gave up this then popular approach as useless.

Instead, he took a new approach when the French government entrusted him with a task in 1904: to develop a method for identifying students with learning difficulties. Together with his colleague Théodore Simon, Binet devised a series of 30 partial exams of increasing difficulty.

In his experience, even toddlers could cope with particularly simple ones, such as following a burning match with their eyes. However, the hardest tasks, including finding rhyming words, require a large vocabulary or other skills that are usually found in older children.

The "Binet-Simon scale", published in 1905 and subsequently continuously improved, quickly found supporters. The German psychologist William Stern suggested dividing the result of such tests (the so-called “intelligence age”) by age: This quotient most closely reflects the developing mental abilities.

A six-year-old child who solved certain tasks that were one year older than the test subjects and thus had an intelligence age of seven years had a quotient of 1.17 according to this formula. To get a whole number - in this case 117 - the result was multiplied by 100.

A good ten years later, the term “intelligence quotient” became popular for this value after the US psychologist Lewis Terman of Stanford University revised the French test.

Terman was convinced that this simple key figure, determined in childhood, could predict success in later life, and he tried to prove this with a long-term study: Using test results, he selected 1,528 children with particularly high IQs and followed their lives over decades .

Despite some remarkable careers in this group: A Nobel Prize was later awarded to two test participants who had fallen out of the IQ elite when narrowing down the IQ elite.

Even if the name has stayed the same: Today, strictly speaking, the IQ is no longer a quotient - because it is particularly difficult to describe the intelligence of adults. For this reason, newer tests are always presented to a large control group of participants of different ages before they are published - in this way, experts are able to determine a typical performance distribution for each age group. The IQ of a person tested is then later based on how far his test result deviates from the average of his peers.

Apart from that, however, more recent IQ tests still work similarly to those in Binet's time: For example, the current version for children (HAWIK-IV) of the “Hamburg Wechsler Intelligence Test”, one of the most widespread procedures in Germany, asks of 15 subtests test several different skills, including language comprehension, processing speed and reasoning.

Intelligence is hidden behind specific intellectual gifts

Sometimes under time pressure, the children have to recreate predefined patterns with colored dice, repeat numerical sequences forwards or backwards and solve arithmetic problems and puzzles read by the tester. As different as these subtasks may appear, one goal of such tests is to capture the “general factor” as precisely as possible - a general intelligence that, according to the theory, is hidden behind all specific intellectual talents.

The British Charles Spearman postulated the existence of such a "g-factor" as early as 1904. He had tested various mental abilities of school children and observed that children who achieved good results in a certain mental area were very likely to do well in other disciplines as well . For example, math talents often also had an above-average understanding of language.

Apparently, so Spearman's conclusion, they had a basic mind that allowed them to solve very different tasks with comparably good results - similar to people with a special athletic disposition who usually achieve good results in several sports.

With a statistical method he developed, Spearman was also able to calculate how strongly the performance in various thought disciplines depended on this assumed general intelligence. Even today, intelligence researchers use this method to determine the extent to which individual test items reflect the g-factor. For example, a test can be put together from such partial tests that represent exactly this size particularly well - as if one were to select mainly sports for an all-around competition in which generalists have the best chances.

Depending on the structure of the finished test, the result, the IQ, is therefore a good approximation of the g-value. For many of its proponents, this general factor is practically synonymous with intelligence - and that can therefore be measured using a simple, one-dimensional scale.

Supporters of this theory refer, among other things, to findings from brain research: Neurologists, for example, examined test persons solving tasks that were heavily dependent on the g-factor, but otherwise very different. Nevertheless, a precisely defined region of the frontal lobe * came into action every time - from this the researchers conclude that general intelligence is located in that area, the lateral prefrontal cortex.

The average IQ grows over time

But since 1984 critics of the measurement of intelligence have been able to make a powerful argument. Back then, the New Zealand psychologist James R. Flynn made a startling discovery when comparing test results from several decades: the average IQ had risen sharply over time. When he then viewed extensive data sets from several nations, he came across the same effect everywhere.

To date, the increase in IQ has been proven in around 30 countries - not least because intelligence tests have to be regularly adapted to the increased level of performance.

If such tests do measure intelligence, the so-called Flynn effect raises several problems at once: if you count back, for example, the majority of our ancestors around 1900 would have had an IQ of less than 70 - and are therefore considered mentally retarded by current standards .

With an average generation difference of nine IQ points in the USA and similar values ​​in other countries, today's children should also outperform their parents mentally - in fact, as a rule, there does not seem to be too great an intelligence gap between the generations.

The alleged generation gap is not the only dilemma in measuring intelligence: According to statistics, there are IQ differences between people of different skin color and members of different social classes. For example, US studies in the 1960s and 1970s concluded that African Americans scored an average of around 15 points less on IQ tests than their white compatriots (a range that is now estimated to have shrunk to around ten points).

In 1994, psychologist Richard Herrnstein and political scientist Charles Murray sparked a heated debate with a series of similar data sets on IQ inequality. In a controversial book, they linked poor test performance with numerous social problems: People with low IQ are more likely to get divorced and more often have illegitimate children, and they are more often poor, unemployed or criminals.

The authors not only emphasized the poorer performance of blacks on IQ tests. They also suggested abolishing childbirth support programs as they would encourage “low-IQ women” in particular to become motherhood. When critics accused the authors of “scientific racism”, 52 intelligence researchers defended some of the views expressed in the book in a public statement.

This included a central assumption by Herrnstein and Murray: that the mental power measured by the IQ is to a large extent determined in the genes.

The idea of ​​intelligence anchored in the genome has many supporters: In view of IQ statistics such as those of Herrnstein and Murray, some do not hesitate to conclude that African Americans are less intelligent by birth. For example, a prominent hereditary proponent claimed that it was now "more or less known" that the IQ difference between blacks and whites was due to "some aspects of the size and functioning of the brain."

Intelligence is inheritable

In fact, some genetic influence is likely. Among other things, studies of identical twins indicate this: Even if they grew up in different environments, they developed a similarly high level of intelligence.

And scientists at London's King’s College recently identified six genes that are strongly related to general intelligence measured by IQ tests (although even the most influential of these genes could only explain fluctuations in this ability by 0.4 percent).

But although some researchers conclude from the twin studies that intelligence is up to 80 percent heritable, other factors such as family situation, school education or cultural background probably have an enormous impact. And so the increase in IQ observed by James Flynn in society can probably not be explained by genetic influence - but perhaps by the change in living conditions in the wake of the industrial revolution.

The work of Alexander Luria shows how people might have reacted to intelligence tests beforehand: In the 1930s, the Russian psychologist confronted illiterate people in remote regions of the USSR with tasks similar to those found in IQ tests. In one case, he made two basic assumptions that his counterpart should logically link: all bears are white wherever it snows, and it always snows on the northern Russian island of Novaya Zemlya.

So the answer to the question of what color the bears were there was pragmatic: “I've only seen black bears so far and can't say anything about things that I haven't seen.” When the psychologist asked, the respondent merely admitted : "If a 60 or 80 year old man told me that he saw a white bear there, he could be believed."

Such subjects would do poorly in intelligence tests: After all, they fail to provide the expected answer, a logical combination of two fabricated statements. The farmers' conviction that experience alone allows a certain judgment about the color of the bears on Novaya Zemlya is true - and exposes the artificiality of the question.

IQ tests measure adaptation to the modern world

Just like the farmers surveyed by Luria, our ancestors around 1900 were not mentally retarded: their intelligence, according to Flynn, was simply more firmly anchored in everyday reality. In contrast, people in today's industrialized nations have long since got used to thinking in abstract categories - and this ability allows them to take IQ tests more successfully.

If this conclusion is correct, then the IQ does not measure intelligence so much as it measures adaptation to the modern world.

Other scientists also consider what IQ tests measure to be a rather limited ability.The US psychologist Howard Gardner, for example, refers to other forms of intelligence - for example that of some autistic children with island talent, who are considered to be retarded in many respects, but have the days of the week in their heads for every date in the past three centuries or at the age of five make perspective correct drawings.

As an alternative to the IQ model, Gardner has therefore developed a “theory of multiple intelligences”. According to this, there are eight independent intelligences: a linguistic, a musical, a logical-mathematical and a spatial (which distinguishes architects, for example), a physical-kinesthetic (common among athletes and dancers), and a natural history. In addition, an interpersonal intelligence makes it easier to work with fellow human beings and an intrapersonal one enables self-reflection.

Gardner's critics complain that his concept of intelligence is too broad - according to her, even gifted baseball players should be described as particularly intelligent. And although there are now "MI tests" for Gardner's multiple intelligences, their practical use is controversial - after all, those skills that the IQ test asks still play a role in school.

It does at least one thing: it can predict an estimated 25 percent of a person's academic and professional performance, making it one of the most informative tools in psychology.

Many qualities influence success in life

In addition to a high IQ, however, other properties also influence success - such as character, as US researchers have impressively demonstrated. In addition to giving a group of 13 year olds an IQ test to fill out, they also gave a closed envelope containing a dollar bill.

The children could either open the envelope immediately or return it intact after a week in exchange for two dollars. The level of self-discipline determined in this way showed twice as high a correlation with school performance as the IQ.

The example of Max also shows that an above-average intelligence quotient does not always guarantee success: The grades of the ninth grader are mixed, in Latin and mathematics he has already written a five or even a six. Such poor performance is not uncommon for highly intelligent students: Without targeted support, they often have problems motivating themselves to attend classes.

Instead, Max excels in areas that are less often associated with giftedness: The 14-year-old documents his work in art class with elaborate multimedia presentations, sets up a school newspaper and submits short stories to literary competitions. While many other young talents suffer from bullying, Max is popular in the class and is even socially involved. He takes a position on issues such as euthanasia or xenophobia - for example by letter to the editor of the weekly newspaper "Die Zeit".

But Max is probably not the normal boy his parents thought he was. Sometimes he complains that the often insensitive way of thinking of most other people almost physically pains him: "It feels like scratching a slate."