When do we say someone is really intelligent? Although there are many ways to measure intelligence, none are ideal. ‘Intelligence is more than a test you complete at a desk.’In BNN’s 2007 National IQ Test, singer Bonnie St. Claire scored 52 points. This meant she scored lower than an orangutan, which scored 75 points. The singer herself said her low score was due to a broken voting box and demanded a rectification, arguing that a low IQ would harm her reputation. ‘Because of this I’m condemned to being seen as a dumb alcoholic blonde for the rest of my life,’ she told De Telegraaf.Singers are not the only people who attach value to intelligence. The concept plays an important role in our society, from schools and companies to dating sites, where intelligence is a quality people consider desirable in a potential partner. Or think of artificial intelligence, a development that suggests that there is such a thing as human intelligence.But what is intelligence exactly? Is it getting high grades? According to the Van Dale dictionary, an intelligent person is ‘quick on the uptake’ and has a high ‘mental capacity’. But the question of what falls under these descriptions is not easy to answer, even for researchers. And intelligence is also hard to measure.Periodic table‘Intelligence is a complex and wide-ranging concept, and everyone has an opinion about it,’ says Loes van Aken, Lecturer in Clinical Psychology. Which is not to say there are no well-defined theories of intelligence, she emphasises. For example, the Cattell-HornCarroll theory, CHC theory for short, which has been developing since 1985, when the three authors first combined their earlier studies into methods for measuring cognitive skills.‘The result looks a bit like a periodic table of elements, the kind that used to hang in your chemistry classroom,’ says Van Aken. ‘Every box contains a different component of intelligence. CHC covers how good a person is with language, how fast they process information, how strong their motor skills are, etc. In addition, the system also takes into account reaction speed.’ Emotions don’t yet have a clear place in the CHC model, though they’re slowly being included. ‘It’s a model in progress; think of it as the latest state of the art.’Eat fishAnother way to look at intelligence is the IQ test, the best-known intelligence test in the world. You can complete an IQ test in a clinical setting, but also on the Internet or in front of the TV, as in the annual BNN test. The most common variants are the WAIS and the children’s version WISC. Both tests are updated on a regular basis; we’re currently using WAIS-IV and WISC-V.The IQ test is not uncontroversial. In 2018, Professor of Public History David Olusoga wrote an opinion article in The Guardian with the revealing title If we were really smart, we’d get over our fixation on the IQ test. The article was written in response to a decrease in IQ scores worldwide and the resulting assumption that we are getting dumber. Olusoga argues that ‘Although modern IQ tests are much more sophisticated than those developed by [Alfred] Binet in the early 20th century, so many factors have been shown to influence the results – everything from eating fish once a week to simply practising the types of questions in the test.’ According to critics, IQ is therefore not a meaningful, stable and reliable measure of intelligence.Clever farmersVan Dale dictionary describes ‘common sense’ or ‘horse sense’ (boerenslimheid in Dutch, literally meaning ‘farmer’s sense’, translator’s note) as ‘cunning’ or ‘cleverness’. It usually means someone who manages fine in life without diplomas or financial resources. The word also refers to those who oppose the elite: the common man with his simple education versus the rich man in a suit with his privileges and expensive study programmes. For example, an article published in Historisch Nieuwsblad entitled Boerenslimheid tegen Britse overmacht (‘Farmer’s common sense against British supremacy’) describes how two small Boer Republics in South Africa successfully resisted British rule for many years.The test is also problematic when it comes to ethnic and cultural diversity. This is a wellknown problem in the US, where Californian schools stopped giving the test to Afro-American children, because it fails to match their experience. In the famous podcast Radiolab Afro-American Psychologist Brandon Gamble gives the example of the question ‘What should you do if you find a wallet in the supermarket?’ The correct answer is ‘Take it to the shop manager’, but Gamble says that he’d never give this answer. ‘It’s the last thing I’d do. Before I know that I’ll be accused of something.’ He argues that this applies to many non-white Americans, including children.In the Netherlands, we also don’t have a good IQ test for people who are, for example, not fully fluent in Dutch, which clearly doesn’t mean they have a low IQ. ‘This doesn’t mean the IQ test is completely useless for this group,’ says Van Aken. ‘You can ask people to complete the questions without text, using images and sums. But images can also contain invisible cultural biases we’re not aware of. We don’t have a test of the same quality that works for these groups.’ In her opinion, this means adjusting the test as best you can for individual cases. ‘You have to be very careful and precise when interpreting the test results.’PlanningVan Aken uses the IQ test in her work as a psychologist, but she’s also done some research on it. ‘I work as researcher and psychologist at the Vincent Van Gogh Centre (a GGZ institution in the Southern Netherlands, Eds.), where we mostly see people whose treatment has come to a standstill because it’s unclear what’s going on,’ she explains. ‘One of the things we usually do is run an intelligence test.’For her research she compared the IQ test used by psychologists to other neuro-psychological tests, which look for example at a person’s ability to plan, or focus on a task.LSD for your EQAnother term that is often heard alongside IQ is EQ, emotional intelligence. Emotional intelligence measures how successful people are at recognising emotions in themselves and others, and how this translates to social success. In the 1950s, the term was sometimes used in dubious ways. For example, a German child psychologist wrote in 1966 that women who rejected the role of mother and housewife lacked emotional intelligence. His proposed remedy? LSD. The term EQ gained respectability after researchers John D. Mayer and Peter Salovey wrote a number of articles about it in the 1990s. However, researchers still debate how measurable EQ is. Many are convinced that a high IQ alone is no guarantee for success, and that a high EQ plays an important role in this context.The IQ test says very little about a person’s thought processes, says Van Aken. ‘Take, for instance, a person who impulsively starts on a task, discovers his method isn’t working, starts again, and finally completes the task faultlessly. In some cases, this person would score as poorly as someone who fails to complete the task because he wasted too much time at the beginning. The test rewards those who work fast.’Which is not to say the IQ test is useless, she says. ‘The test doesn’t pretend to measure more than it measures; it’s not a test for everything. IQ is not the same thing as intelligence, but it’s still the best tool we have for measuring the complex construct that is intelligence. It remains an estimate, though, so we always have to look beyond IQ scores. But despite all these limitations, the IQ test is much better at assessing intelligence than we are.’Social interactionAssistant professor Leon de Bruin agrees with Van Aken’s conclusion. He’s an expert in Philosophy of Mind and Cognition, a discipline that attempts to understand the human mind. ‘People are afraid of artificial intelligence taking over,’ he explains. ‘This fear is based on our belief that intelligence is separate from everything else: from emotion, from our body, from our environment. I don’t think that’s correct.’He uses the example of students he meets as a teacher. ‘I sometimes see students who are highly intelligent, but who can’t seem to apply their intelligence because of work pressure, depression, or social problems,’ he says. ‘Intelligence must be facilitated by environmental factors, which doesn’t always happen, for example because of social interaction problems. All this plays a role.’Anyone can flyReally clever criminals appeal to our imagination. One example is Frank William Abagnale Jr, an American who defrauded banks of an estimated total of two and a half million dollars in the 1960s. He flew for free to more than 25 countries by impersonating Pan Am pilot Frank Williams, with the help of a stolen uniform and fake flying license. In those days, pilots could fly for free with all airlines. Abagnale then impersonated a paediatrician for a period of eleven months, working as chief resident paediatrician in a hospital, and avoiding discovery by getting interns do his work for him. He was finally arrested and served sentences in France, Sweden and the US. He was later conditionally released in exchange for helping the US government and banks combat fraud. His extraordinary life story inspired the film Catch me if you can (2002), with Leonardo DiCaprio in the role of Abagnale Jr.Philosophy shows that people’s ideas about intelligence have changed over the centuries, says De Bruin. ‘For example, look at Aristotle and his concept of phronesis, which refers to the ability to know what to do at any given moment, having the know-how to do the right thing in a situation, a kind of practical wisdom.’ These days we’d use the term ‘common sense’ to refer to this kind of practical intelligence. ‘But for Aristotle, phronesis also had a moral dimension, which isn’t part of our concept of common sense,’ says De Bruin.With regard to common sense, Van Aken says: ‘It’s certainly important to be able to adapt to your environment. Navigating situations smoothly, dealing with complex situations, taking responsibility for your problems and solving them, these are all forms of intelligence. It’s just difficult to talk about intelligence or cleverness in other ways, because we have no better measuring tool than the IQ test.’ And that test doesn’t measure things like phronesis or common sense.‘How we look at intelligence is also linked to what we think of as normal or abnormal,’ says De Bruin. ‘Our society requires very different things from us than it did sixty years ago or so. People now have to be good at many more things.’ He mentions the example of social interaction. ‘Many people find social interaction difficult, which can result in them appearing less intelligent.’ Finding ways to deal with this is also a form of intelligence, he says. ‘To understand how intelligent a person is takes more than a test you can complete at a desk.’Text: Jozien Wijkhuis. This article previously appeared on Voxweb. Photo: Gerd Altmann via Pixabay.