Superhuman 1 INTELLIGENCE
Suppose knowledge could be reduced to a quintessence, held within a picture, a sign, held within a place which is no place. Suppose the human skull were to become capacious, spaces opening inside it, humming chambers like beehives.

—Hilary Mantel, Wolf Hall

You know it when you see it. I saw it in an orangutan once, a young male in Malaysian Borneo who had been orphaned by deforestation. I was hiking around a protected area of rain forest with a primatologist friend when we came across him.

Because he had been raised in a rehab center, he was well disposed to humans, and, it turned out, especially fond of men. He came bounding over. I was nervous as this juvenile but powerful ape tugged at my clothes and tried to climb up me as if I was a tree. I pushed him away a few times, and he finally sat on his haunches, looked up, and held out his hand. I remember taking the hand and feeling it clasp gently and warmly and softly around mine. I caught his eye. In it there was a complex look, a mixture of exasperation, cajoling, and hope; he was fed up with me pushing him away, but hoped I would understand that he just wanted to play.

You know intelligence when you see it, and I saw it in him. After that handshake and the look that passed between us, we played for a good hour, which mostly consisted of him climbing up me and me swinging him around. He was basically a monstrously strong, hairy, orange toddler. He was six years old then and sometimes I wonder what happened to him, and whether he’s safe in that protected fragment of rain forest.

It’s a special memory for me, but the anecdote exposes several problematic issues with the study of intelligence. Perhaps I was projecting those feelings on to the animal. Many people would say they’ve seen dogs with the same look in their eyes. Dogs and orangutans might well be intelligent in some sense—but in what sense? How do we measure it?

To study intelligence, we need to be able to define it and measure it, and both things are surprisingly tricky. It’s not something like height, which is easy to measure, though crucially intelligence is like height in that people have varying amounts of it. Intelligence is complex, multifaceted, shifting, and slippery, and it’s the quality we revere above perhaps any other. How strange that we find it hard to agree on a definition. Here’s what the American Psychological Association Task Force on Intelligence settled on: “individuals differ from one another in their ability to understand complex ideas, to adapt efficiently to the environment, to learn from experience, to engage in various forms of reasoning, to overcome obstacles by taking thought.” That’s fine, but I want to know how artists and scientists create and develop new ideas that take us places we’ve never been.

•  •  •

Intelligence is something we can easily recognize in others, and with IQ (Intelligence Quotient) tests we can measure at least some aspects of it, but giving it a value doesn’t tell us what it’s like to be more intelligent. And what about those people who have never had an IQ test? We’ll have a look at IQ later in the chapter, but I want to start—as I’ll do throughout the book—by meeting people who exemplify the trait in question. So-and-so might have an IQ of more than 150, but how does that make them feel? Where does intelligence come from? What benefits, if any, does it bring? How do people with a surplus of it see the world? Can we load the dice so our children have more of it?

•  •  •

The first person I’ve decided to meet in this examination is a chess grand master. I chose chess because it seems to be a game of pure intellect, or one that is at least highly cerebral. It has also been extensively studied by scientists. It’s been said that chess is to cognitive science what the fruit fly Drosophila, perhaps the most well-studied organism on Earth, is to genetics.

John Nunn is one of the finest chess players of all time. At his peak, he was in the world top ten. When he was fifteen, he went to Oxford to study math, becoming the youngest undergraduate since Cardinal Wolsey in 1490 (thus handily providing me with a thematic link to someone else we’ll meet in this chapter), and went on to take a PhD in algebraic topology, a subject into which I can offer no meaningful insight whatsoever.

Nunn turned chess pro at twenty-six. He was clearly something special, yet while he did scale great heights, he didn’t claim the top prize. Commenting on why Nunn, now sixty-one, never became a world chess champion, Magnus Carlsen, the highest-ranked chess player in history, said Nunn was too clever: “He has so incredibly much in his head. Simply too much. His enormous powers of understanding and his constant thirst for knowledge distracted him from chess.”

It’s fair to say I’m a bit intimidated ahead of meeting John Nunn. Aware of my hazy understanding of his field of math, I turn to Wikipedia, which tells me its goal is “to find algebraic invariants that classify topological spaces up to homeomorphism, though usually most classify up to homotopy equivalence.” I am none the wiser, and possibly even less wise than before. It would make a nice story to have us chatting over a game of chess, but I don’t even want to suggest it. There’s no false modesty here: it would embarrass him to have to stoop so low. It would be like me suggesting to Usain Bolt that we have a quick run around the park. This is the man who in 1985 beat Alexander Beliavsky from the Soviet Union in a match described as “Nunn’s immortal.” Chess Informant, the bible of chess information for players and scholars—a sort of chess Wisden—lists the Beliavsky match as the sixth best game ever played, from 1966 (when it started recording matches) to the present day.

We’ve arranged to meet in a coffee shop in Richmond, south-west London. I get there ten minutes early and secure us a table. Our communication up until now has only been by email, and as such our relationship has been rather formal. I’ve no idea what he’s going to be like in person, but here he is, rocking jeans and Converses, with a black motorbike jacket over a hoodie. I hadn’t really thought about what he’d look like, but now that I’ve seen him I realize I didn’t expect such a groovy grand master.

He started playing chess at four. As far as his memory goes, he says, he could’ve been born playing chess. “I don’t really remember learning to play it.” But it soon became clear that he had an innate talent. How did it become clear? “Well,” he says mildly, “when you start winning lots of tournaments it’s pretty obvious.”

Immediately it feels we’re on to something interesting about intelligence. When Nunn says he had an innate talent at chess, he’s saying that genetics played an important part. Of course he had to learn the game, but he claims to have had a natural skill that helped him become good at it. This cuts to the heart of what talent is, and the extent to which expertise in something develops through innate ability and practice. It’s something we’ll meet repeatedly throughout this book.

There are two schools of thought when it comes to understanding expertise, and they broadly divide along the long-drawn lines of nature or nurture. On the nurture side is Anders Ericsson, a Swedish professor at Florida State University’s department of psychology. His work was behind the popular (if now widely criticized) idea that 10,000 hours of practice at anything will make you an expert (we’ll come back to this in Chapter 6). Deliberate practice, Ericsson says, can allow anyone to achieve exceptional performance.

I said that the two camps divide along the lines of nature and nurture, but the problem with the whole argument is that the lines shouldn’t really exist. Nothing works alone. Genes need an environment to work in and no amount of practice will help if you just don’t have the genetic tools in the first place. The argument is really over the relative importance of genes and practice.

Zach Hambrick, who runs the Expertise Lab at Michigan State University, could be said to represent the opposing camp to Ericsson. “Practice is certainly an important factor,” Hambrick tells me, “but [it] doesn’t account for all the differences across people in terms of skill, so other factors have to contribute.” And the factors we’re all interested in are the genetic ones.

Look at Magnus Carlsen, the highest-rated chess player in the world by a wide margin. Yet an analysis of the amount of practice he and the next ten highest-ranked grand masters have put in shows he has practiced for significantly fewer years than the other players.1 Does he have talent? In other words, is there a genetic advantage to his ability? “The answer to this question is so obvious in the chess world that it is not even posed—Carlsen is known as the ‘Mozart of chess,’ ” say the authors of the analysis, Fernand Gobet of the University of Liverpool and Morgan Ereku of Brunel University.

We’ll return to the role of practice in the chapter on music, so for now let’s go back to Nunn and dig deeper.

“Magnus Carlsen said of you,” I say to Nunn, “that you were effectively too clever for your own good, and that’s why you never won the world championship.”

“That was very nice of him,” Nunn says.

“Is it true?”

Nunn shrugs. “Maybe he was right. To be really successful you have to be a monomaniac. To devote your life to it. Some people just can’t. They have other interests, they’re not happy if they spend their whole life focused on one thing.”

This seems to ignore that Carlsen himself has a life outside chess. Carlsen says his other interests involve chatting with friends on the internet, playing online poker, skiing, and playing football.2 But those enterprises are not the cognitively demanding interests that Nunn has—astronomy, physics, and extremely arcane and high-level math.

“If you’re one hundred percent committed, it’s very painful when things go wrong,” Nunn says, “because you don’t have anything else to fall back on.”

Things will inevitably “go wrong” in most fields of endeavor, as performance and ability start to decline with age. Nunn coped with that by quitting. Numerous studies have shown that what’s called fluid intelligence, which relies on working out abstract problems, and speed of mental processing, both decline in efficiency after about the age of thirty. On the other hand, another subset of intelligence, known as crystallized intelligence, which utilizes real-world information, maintains its peak level for many years before slowly declining. Nunn seems reluctant to accept that anything about his brain function has changed, and indeed says that his chess ranking has stayed about the same since his professional playing days.

“What changes is you have [a] family and have other priorities,” he says. “You don’t want to focus exclusively on playing chess. But just for age reasons you get tired more quickly. I still feel I can play as strongly as I did but, you know, you play a long tournament, it’s exhausting.”

I spoke to Neil Charness, professor of psychology and director of the Institute for Successful Longevity at Florida State University. Charness and his Florida colleague Roy Roring conducted a study of the change in chess ability across lifespan.3 Using a database of 5,011 chess players, they found that the average peak age—the age at which players on average attained their peak rating—was 43.8 years. They also found that age is “kinder to the more able,” meaning that more highly skilled players tend to show milder declines in rating when past their peak age. “The problems for older players,” Charness says, “are probably similar to those for any aging adult, namely that learning rate slows.” Learning rate drops off by half between your twenties and sixties, and as a result there are lots of rising younger players who can outwork you and beat you. While we’re on the maudlin topic of cognitive decline, Charness adds that there are probably some age-related changes in motivation. Also, brain efficiency declines in a number of ways, including memory, attention, and speed of processing. “So, although chess for humans is mainly a game drawing on pattern recognition and knowledge, and despite the fact that you can keep learning throughout life, you may have problems retrieving the relevant information in a timely fashion.”

All this seems to tally with Nunn’s experience. But I’m interested in how people at the peak of human potential have gotten there, and I want to find out what it was like when he was younger. Nunn says sure, he felt different from other kids. Was it obvious to him that he had this strength? “If you keep winning tournaments it’s pretty obvious,” he says. “I won the London under-twelve championship when I was nine.” Did his success make him cocky? He says he was a balanced kid, if slightly solitary, with friends his own age.

What other signs were there, if any, that there was something different about him? “When I was very young, before I could read, my parents noticed I was looking through all the books in the bookcase, and they said, ‘What are you doing? You can’t read’—and I said I was looking at how many pages there are in each book. I’d worked out how the numbering worked at the bottom of the pages. So they asked me how many pages there were in certain books, and I knew. So I would say my mathematical talent was evident early on.”

Nunn passed A-levels in pure math and applied math in his midteens. But why go to university so young? “I wanted to go. I was fourteen. If I didn’t go, I’d be hanging about for years. Not a good idea, really, for a teenager. So I wanted to go, and my parents agreed. It all worked out quite well.”

I wonder if there was a similar discussion in the Wolsey household when young Thomas (later to be Cardinal) Wolsey went up to Oxford to read theology at fourteen. There would be no younger undergraduate for more than five hundred years, until Nunn himself. (Incidentally, there has since been a younger undergraduate. In 1983 Ruth Lawrence went to Oxford at the age of twelve. Her field of study? Algebraic topology.)

What about looking after yourself at that age? Most students can’t work the washing machine. “That was very tricky,” he says, in a way that lets me know that it wasn’t tricky at all, “but I figured it out.”

More challenging was social life. At university, Nunn was too young to drink. “The difference between fifteen and eighteen is quite a lot. A lot of activities don’t appeal very much. On the other hand, I had mathematician friends and friends at the chess club. By the time I was seventeen, it all felt normal.”

Nunn’s assessment of his ability and his success mirror the sort of thing Hambrick sees in his research: that expertise is built on innate skill. “I think my talent in chess and math was inherent,” says Nunn. “But in any activity, if you want to go to the top, you have to have talent and put in the work.”

I started by assuming that chess was a game of pure intellect. Does that mean people who are chess experts are also more intelligent than average? It appeals to common sense that this would be the case, but it’s controversial. Chess experts tend to practice intensively for years, and it’s hard to separate that from innate talent or intelligence.

Hambrick, always keen to determine as far as possible the relative roles of practice and skill, looked into the question with his colleague Alexander Burgoyne, also at Michigan. Burgoyne combed thousands of studies of chess skill, and selected nineteen studies containing some 1,800 participants that included measures of objective chess ability and cognitive ability, which in practice means the IQ score. Overall, the team found a link between intelligence and chess skill. “General intelligence and general cognitive abilities correlate moderately with chess,” Hambrick says.

The link was only moderate, perhaps because the top chess players are all of above-average intelligence. There was a stronger link between chess ability and intelligence in younger players and those at lower levels. Hambrick says that might be because highly intelligent people can become good at chess quickly. Average people can become good but need to practice much more. A follow-up study in 20174 aimed to test Ericsson’s claim that experts become experts not just because they are smarter, but because they have better access to training.5 Ericsson’s idea is that if scientists or musicians have higher IQs than nonexperts, it’s because people with higher IQs get selected for expert training at universities. The traditional view is that IQ itself predicts who will become an expert. So the arguments differ on the role of training, with Ericsson emphasizing the training. Hambrick’s team tested this by comparing chess players with others who don’t play chess. The rationale is that in chess there isn’t the selection process we see among scientists and musicians trying to gain a position in some academy, so if Ericsson is right, then there should be no difference in IQ between chess players and non–chess players. But there was a difference: chess players outperformed non–chess players in cognitive tasks, meaning that training alone can’t explain expert performance.

So what innate skills might these be? For chess, Nunn says you need a power of visualization to see what the options are going to be in four or five moves. You need a good memory. A good ability to calculate. You need skills of pattern recognition. Starting young is important in chess. Studies have found that even after controlling for amount of practice, the younger you start, the higher the ranking you are likely to attain.

According to Charness, pattern perception plays a critical role in optimizing the search process that chess players use when trying to find the best move, “So if there are any innate or genetic differences, I would be looking for someone having slightly more fluent pattern-abstraction processes.” Not that this means there is such a thing as a chess-playing gene. “It is hard to see there being evolutionary pressures for expert chess playing, despite the occasional bumper sticker you see that proclaims ‘chess players mate better.’ ”

All this has helped enlighten me about the components of intelligence that chess players seem to have at a high level, and I understand better how chess skill develops from a young age and tails off with time. But these things don’t convey how it feels to play, and they don’t tell me what it is about Nunn that got him into the world top ten. So after our chat I watched a narrated reconstruction on YouTube of “Nunn’s immortal”: the fabled game against Soviet grand master Beliavsky. The reason the game is revered is that Nunn discovers an extraordinary response to Beliavsky’s white pieces (aligned, if this means anything to you, in the Sämisch Variation of the King’s Indian) that suggests an apparently strong attack for white. Seeing black apparently blunder, white makes the attack. Black then sacrifices one of its knights. A piece down, it would seem the game is up, but black manages to contrive a net from which white cannot escape. Watching the reconstructed game, I think I can grasp the beauty people see in it. Nunn glimpsed something that was possible in the vast gamespace of potential outcomes, but that was concealed from everyone else, even other grand masters who afterward analyzed the game. This is how chess can achieve the quality we normally associate with art. The Beliavsky–Nunn game represents an idea that hadn’t been thought before.

“I was aware during the game that it could be something special, a once-in-a-lifetime opportunity, and I was really motivated not to spoil it by inaccurate play,” Nunn says. “In the event, everything went well, and afterward I was delighted with the game.”

I ask Nunn if he’s ever had an IQ test. He has, when he was young. But he doesn’t want to tell me what the result was. “It was rather high, I think it was unrealistic.” I wheedle the score out of him, but only by promising that I won’t publish it. But I can report that yes, it is “rather high,” if by “rather high” you mean snow-capped and exalted mountain peaks far beyond the troughs, bogs, and modest hills of the vast majority of the human species. I goggle at him, mouth flapping open. “So what,” he says. “It doesn’t mean anything, I suspect.”

•  •  •

Let’s make a short diversion into IQ.

When he says his IQ score doesn’t mean anything, Nunn is perhaps allowing his modesty as to its value to influence his appraisal of the worth of IQ testing. It’s significant, however, that he denies the value of IQ testing, saying that it merely tests how good you are at doing IQ tests. “This is a bit like a multibillionaire saying ‘Oh, well, you know, I get along, but money isn’t everything,’ ” says Stuart Ritchie, an intelligence researcher at the University of Edinburgh’s department of psychology. You do however hear this criticism a lot, so let’s take a look at it. IQ scores correlate closely with a wide variety of life outcomes. “If we were able to take a step back and look at the whole range of people, with much lower and much higher IQs than ourselves, we would start to notice patterns in how it relates to education, health, job success, longevity, and so on,” Ritchie says. “IQ measures something that seems to be pretty important in life, not just how good you are at doing the tests.”

Here’s a powerful illustration of that. In 1947, around 94 percent of the Scottish population born in 1936 completed an IQ test. The test has high lifetime stability, meaning the score the children received at eleven will correlate well with their intelligence scores later in life. In 2017, researchers managed to follow up on more than 65,000 of these children. They found that the higher the value of childhood intelligence, the lower the risk of death from a variety of causes.6 This included death from respiratory disease, heart disease, and stroke, and also from dementia and suicide. Socioeconomic status had only a modest impact on the likelihood of dying.

I’ve never had an IQ test. I’d be nervous to take one because I worry that I wouldn’t get a decent score. Actually, this fear is misplaced. Findings about IQ such as those discussed in the Scottish study are always based on IQ scores averaged across populations. For individual people, a high or low score is not a good predictor of success, of failure.7 But the more important concern for many people is that it feels like we can potentially order people in merit by their IQ score, when of course there is much more to human life. This is the “I won’t be reduced to a number” argument. Here are two slam-dunk replies to that. First, says Ritchie, “Nobody ever said it was a single number.” No one claims your IQ represents your life. IQ is a convenient summary number, but researchers build statistical models of a whole hierarchy of cognitive abilities, going from specific to general, and look at how these relate to different life outcomes.

Second, if we refuse to reduce complex things to numbers, we can’t investigate them scientifically—this relates to everything from psychological testing to climate science. “We’re all crushingly aware of how complex intelligence is,” says Ritchie, “and these numbers and models are just a first step along the way to really understanding why some people are smarter than others.”

The IQ test may be the most controversial measure in science, but psychology has no more rigorously designed and sophisticated assessment. “All tests and surveys have problems,” says Dana Joseph, a psychologist in the Department of Management at the University of Central Florida, “but intelligence tests have been studied more than perhaps any other type of test, so these problems have been minimized as much as possible.” IQ tests don’t cover all forms of intelligence, but no test covers 100 percent of the construct it intends to measure, and IQ has proved robust across a range of measures. “We have evidence suggesting that many intelligence tests capture intelligence fairly well,” she says.

A proper IQ test measures a range of different abilities—memory, reasoning (both verbal and abstract), general knowledge, speed of brain processing, and spatial awareness. The results for each subset of tests are crunched together to give a final score, and the average for the population is set by the testing companies as 100. Many of us might say something like “Oh, I’m great with words but hopeless with math” or “I’m good at reasoning but I’ve got a rubbish memory”—we feel we have strengths in certain areas but not in others. But here’s the odd and powerful thing about IQ: people good in one subset of the test tend also to be good in others. All the measures come together to give the “general factor of intelligence” that researchers call g.

IQ isn’t the same as the general factor of intelligence, but because it samples lots of different aspects of intelligence it correlates closely. A vast amount of work over many years has shown that people with high scores on intelligence tests do better when they are at school and at work, and even have better health outcomes. We also know that there is a genetic influence on intelligence. There are many genes that each have a small influence on intelligence, which is what we’ve come to expect from complex traits. When the genetic effect has been measured, it turns out to be smaller for IQ than it is for g. In other words, cultural, educational, and social factors seem to have more influence on IQ, whereas g is more biological. When you follow people with high IQ throughout their lives, they tend to be extremely successful: they are more likely to get important and powerful jobs, and become influential in many different spheres of life, from art to music to politics to science. They tend to be healthier because they make better decisions. Incidentally, you are more likely to match your spouse for intelligence than for other traits. The correlation for IQ between spouses is about 40 percent; it is about 10 percent for personality and 20 percent for height and weight.8

Deep criticisms remain. One of the most troublesome is that any differences in IQ found between different groups of people—say, African Americans and white Americans—could be used to suggest that there are real differences in intelligence. More likely is that if any such differences exist, they reflect socioeconomic and cultural differences, such as the experience of racism and poverty, rather than anything genetic.

Another criticism is that IQ ignores emotional intelligence, that is, the ability to understand what others are thinking and feeling. (It’s worth mentioning here, as the journalist Adam Grant points out, that important historical figures who had a powerful command of emotional intelligence include Martin Luther King Jr. . . . and Adolf Hitler.)9

A measure of emotional intelligence is thought to be useful in assessing candidates for jobs involving interactions with people, though work by Dana Joseph and her colleagues suggests that regular IQ tests are better predictors of performance.10 It seems that the IQ test does the job better than other tests designed with different forms of intelligence in mind.

In summary: yes, there are issues, but IQ is the best measure of intelligence that we have and correlates strikingly with a range of lifetime outcomes. Having said all that, I’m well aware that intelligence is broad, complex, and rich, and manifests in any number of different ways. I still want to investigate people with different forms of intelligence, so I’ve arranged to meet one of our greatest living writers.

•  •  •

Before I meet Hilary Mantel I try to get into character. I walk a short stretch of the Thames in west London, from the Ship pub in Mortlake along a wall that traces the same boundary as did, five hundred years ago, the wall of Thomas Cromwell’s manor. Henry VIII made his chief minister Lord of the Manor of Mortlake in 1536. I imagine turning a time-travel dial that would rewind the clock 481 years so I could see Cromwell stepping off the barge from the city, perhaps with a small entourage of staff, after advising the king in court. I try to imagine the area without the modern houses and the pub and the old brewery and Chiswick Bridge. All these things fall away rapidly and there are still hundreds of years left to rewind. Only the shape of the river is the same now as it was in Cromwell’s time. Perhaps there are a few old oaks around that were young half a millennium ago. I can’t really picture the scene—not like Hilary Mantel, who has pictured it, researched it, imagined it, and practically lived it.

Mantel was already a successful novelist before she started writing about Thomas Cromwell. (He, incidentally, must have been one of the most intelligent people in the Tudor period; certainly he was one of the most influential.) But the first two books in Mantel’s Cromwell trilogy, Wolf Hall and Bring Up the Bodies, both won her the Man Booker Prize (she’s the first woman to win the award twice) and propelled her to international acclaim. In 2013, Time magazine named her one of the hundred most influential people in the world, and she’s widely considered one of the world’s finest living writers. The depth of her characterization and the intelligence of her writing is remarked upon by almost every reviewer. If anyone is a candidate for inclusion in this chapter, it’s her.

“It’s vaguely mock Tudor,” Mantel says when giving me directions to her flat—how appropriate that she lives somewhere that is a modern take on a Tudor style.

It’s no surprise that the first thing she identifies as a special skill is her way with words. “The family story,” she says, “is that I didn’t speak and didn’t speak and didn’t speak, until I was about two and a half—and then started talking like an adult.”

She says when she thinks back to her early memories they don’t feel like what we think of as a child’s memory. It’s as if the young Hilary experienced an accelerated mental maturation. “It’s almost as if there was a much older person sitting inside me.”

She thinks her linguistic fluency is an innate characteristic. As a young girl, she’d sit for days in the company of her grandmother and gran’s sister, who would talk constantly, almost ritualistically, perhaps varying only slightly what they’d said the day before, but Hilary would be soaking it all up. By school age she’d acquired an enormous vocabulary. She had been the only small child amid a mass of adults and had become minutely attuned to the rhythms of their language. “That’s where my weird vocabulary came from when I went to school. When I wasn’t speaking, I think I was working it out, and only speaking when I was good and ready.”

This knack for language is something untrained in the sense that neither Mantel nor other members of her family studied it; her mind seems like it was ready to use correctly everything it heard. “We’re all good talkers. Even my mother, who left school at fourteen, never makes a mistake in syntax or grammar. She can carry the longest sentence—it may be nonsense in context, but it’s perfect in form. And I think of that as something that must be inherent.”

We’ve seen already how IQ accurately reflects intelligence, and how it correlates with many aspects of our lives. That in itself has been controversial, but it’s less so than the idea that some components of intelligence are inherent. To investigate this, I go to see Robert Plomin, a Chicago native long since transplanted to Britain, where he is professor of behavioral genetics at King’s College London. Plomin launched and runs the Twins Early Development Study (TEDS), the UK’s largest study of twins, involving more than 15,000 identical and fraternal twins who have been assessed from early childhood to (currently) the age of twenty-one.11 Because twins share their genes and almost the same environment, it’s possible to examine a trait such as intelligence—but also many other traits, like obesity—and determine how much is influenced by genetics and how much by your environment. Plomin also looks at twins that are raised apart, as well as adopted children,12 and his conclusions are robust, clear-cut, and somewhat shocking. Most of the child’s academic achievement until the age of sixteen is explained by genetics. It doesn’t matter what kind of school the kid goes to, or the kind of home it is reared in—the IQ of the separated child correlates very closely with that of its sibling, or its birth mother. It doesn’t correlate at all with the IQ of its foster sibling or adopted mother. “All the different approaches: adoption studies, identical twins, twins reared together and apart, they have different assumptions but they all converge exactly on the same conclusion. Genetics is much more significant an influence than school or home environment. I don’t see how people can deny the data,” he says.

In a study of 360,000 sibling pairs and 9,000 twin pairs, Plomin and colleagues found that high intelligence, of the sort we’re exploring in this chapter, is familial and heritable: almost 60 percent of the differences in high intelligence are genetic.13 This supports Mantel’s intuition that a substantial part of her intelligence is inherited.

There are no “intelligence genes,” however. Or rather, there are, but there are thousands of them, each with a tiny effect on intelligence, and with effects on other traits. In 2017, a genetic analysis of 78,308 people found fifty-two genes that together explain less than 5 percent of the variation in intelligence between people.14 If it’s confusing that 60 percent of intelligence is genetic but the study only found 5 percent, it’s because specific genes are hard to find. That 5 percent refers to specific genes, and scientists are working on finding the other 55 percent.

Mantel doesn’t call herself a perfectionist, but she cares passionately about getting things right. “It seems I was always preparing to be a writer. I was always finding the exact words for things, nothing vague would do.” (My response to that was that it also seems like good training for being a scientist.)

By her own reckoning, a good memory and an extreme verbal fluency are her outstanding qualities (and we’ll look into these in depth in Chapters 2 and 4). Sometimes she slips into talking about herself in the second person, and the effect is a little like reading her Thomas Cromwell books, which often use the pronoun “he” to refer to Cromwell. “You perceive your general intelligence wouldn’t come out that high on a test,” she says, “but what I’ve got that an IQ test wouldn’t tell you is a pretty good memory, and a capacity to mince industrial quantities of data.”

As it happens, a proper IQ test does measure memory, but perhaps not the long-term memory Mantel is talking about. In any case, Mantel turns out to be one of those people we’ve just considered in the discussion on IQ: she thinks she’s good with words but bad with numbers. “I always thought the world was overrating me because I was so verbally fluent. And I could bullshit my way through an exam paper. With mathematics it’s a complete blank. I’m not innumerate. But I remember sitting through the first lesson in calculus and it might’ve been given in Russian for all I understood.”

This is harsh: calculus is not easy even in your native language. I mention that although you often hear people saying things like “I’m good with words but poor with numbers”; a lot of intelligence research has shown that clever people are clever across a range of different kinds of intelligence. Perhaps she just didn’t get the nudge she needed to be good at mathematics. She considers this and revises her opinion. “I had this hobby of working out immensely complex multiplications. I wasn’t against numbers. But when it became conceptual rather than mechanical, there was something I wasn’t getting.” It’s a classic case of how a slight “tilt,” as psychologists call it, toward one type of ability, can influence your life’s trajectory.15 In Mantel’s case, of course, she tilted to becoming a novelist.

Extremely intelligent children are often lonely, basically because they are bored with kids their own age. As a small child, Mantel says she formed a habit of ignoring people who asked stupid questions. She perceived a lot of school as a waste of time. She found it difficult to make friends. “I think people thought I was crippled by shyness. I was always on the outside of a group. I would be the person who would think of the game, and everyone else would go off and play it. It’s typical of what writers say, they’re watching everyone else.”

She says she was frustrated, rather than unhappy. “But then I had a feeling of biding my time. I was always trying to get somewhere. I had boundless but completely unformulated ambition. So whatever was happening, I regarded it as only temporary.”

I think this is getting at something that seems to be key to the way intelligent, or at least successful, people function: ambition or drive. “You had a drive,” I say.

“That’s right. To put your mark on things. It wasn’t ‘I will leave this small town and I will show them,’ it was more that—you know those experiments they do with children with marshmallows about deferring gratification? I’d’ve been great at that.”

The marshmallow test was devised by Walter Mischel at Stanford University in the 1960s. Children were presented with a treat and told they could either have it now, or they could wait fifteen minutes and have two. About a third of the children managed to hold off eating the marshmallow and reap the reward. Several years later, to his surprise, Mischel found that the kids who had shown self-control ended up doing better both socially and academically. The result has been repeated in a number of different ways, and forty years later, when the kids had grown up, researchers tracked them down and found there were differences in the adults’ brain networks according to their powers of self-control. Kids, now adults, with better willpower had predictably different patterns of neural activity.16

Another study found that people with better self-control were more intelligent, and brain scans suggested there was more activity in the anterior prefrontal cortex.17 This is one of the last parts of the brain to mature, and listening to Hilary Mantel’s story, it’s tempting to suppose that her brain really did mature more rapidly. She imagined that there was an older person sitting inside her, but I wonder if her intuition may be tapping into something real.

“When I think back to the judgments I made of people as a child, they often seem more like adult perceptions,” she says. “I think I was just amused by people. And if you’re looking for the next mad or quirky thing they might do, or you’re looking for them to manifest themselves in some extreme way—then you’re not so frightened of them, as children can sometimes be. You’ve detached yourself.”

She checks herself and mentions that she’s just hit upon something she hadn’t known before, about waiting for people to manifest themselves. “You have an idea about someone and then you wait for them to prove it to you in their behavior. I think that’s how I operated. As if there’s a play to be put on and I was sitting waiting. Not that it wasn’t painful. No child likes to feel an outsider. But I don’t think I was damaged by it.”

Kristine Walhovd is a professor of cognitive neuropsychology at the University of Oslo in Norway, and one focus of her research is looking at how the brain, and cognitive ability, changes with age. I ask her about how evidently highly intelligent people such as Hilary Mantel might feel different, and how this might be explained. Walhovd stops me getting carried away:

“We are all unique, so when Mantel comments that she felt different, that is of course true. We all are. I bet if being honest, most people, like Mantel, would say that they felt different to ‘the others’ at some point growing up. Wouldn’t you? And we are all right, we are different to everyone else, but so are ‘the others.’ ”

Well, that’s good. It’s my aim after all to demystify people at the extremes. Mantel is not uniquely different, of course she isn’t. Nor was her extreme verbal ability an extreme sign of the difference in maturation rate of boys and girls: Walhovd says the sex difference is overrated.

If there are qualities that Mantel has had since she was a girl, they are a certainty of herself as an individual, determination, and focus: “I’ve always had a strong and definite sense of self that didn’t depend on what other people said or how they viewed me. I see myself as being obdurate, like a stone, inside.”

All her projects, since she was quite young, have been big and long term. She knows that something won’t pay off for five years but then it will. But why was she deferring gratification? What was her marshmallow?

“It’s that when you set your intention, your intention will keep moving ahead of you as you move toward it. And by the end, you will have done something bigger and better than you could imagine, and you will have changed and you will have more capacity. So it’s always just keeping ahead of you and stretching what you can do.”

If challenging and developing herself was and is her goal, she identifies the driver of this development. “Curiosity is the basic thing, I think. You really have to be asking yourself every morning, what could happen today? I can see that if you consistently maintain that mind-set it will keep your mind lively into old age.” She pauses before continuing: “Your body’s different, of course.”

Mantel has suffered poor health for many years, and a lack of physical stamina is one reason, she says, that she didn’t go into politics. She picks up again. “And I perceive that a happy life is one where even way into middle age you’re still finding new capacities.”

We’ll come back to what constitutes happiness at the end of the book. For now, I want to ask Mantel what I think of as the Atticus Finch question. One of her strengths is her ability to understand the human condition from different viewpoints; it’s her knack of getting inside a character’s skin. How does she do it? She says she thinks of writing as a performance where you have to play all the roles. “If it’s a character who’s plucked out of your head, then I perceive them to be in some way aspects of yourself, an exploration of unused sides of yourself, like if you were a man, what kind of a man would you be? So you’re playing out your unlived lives.”

Mantel says that with her main characters, she can’t see through their eyes, only just to the side. “You try to give the main characters free will,” she says—I think of Cromwell, and I’m sure she does too—and they feel indefinite around the edges. I didn’t grasp what she meant at first, then later on I think she is not omnipotent about them because her main characters are so deeply realized that they almost become their own people.

Her creativity, as she sees it, comes from self-examination. “I’m keenly noting what passes inside my head and am not so focused on what’s happening in the real world,” she says, which leads her to a defense of the pen-chewing, mind-wandering, drifting writer: “People misunderstand what they call daydreaming.” She then intuitively states what psychologists have only just discovered using brain scanning.

“For a writer, daydreaming is extremely purposive. It’s directed. And what you see in your inner cinema reel will get translated into words, or stored and you’ll rerun it, but it’s not at all a hazy activity.” Paul Seli at Harvard University has shown that mind-wandering is indeed linked to purposeful thought;18 other studies have indicated that daydreaming can boost creativity and aid problem solving.19

“There’s a lot of conflict in myself because I really like to know the facts,” she says, and again I think of the similarities with science. “A lot of creativity is about tolerating ambivalence. All the time you’re dealing in layers or shades of meaning.”

•  •  •

Let’s turn now to someone who also likes to know the facts, but has a superhuman intolerance of ambiguity.

Paul Nurse, who has a string of letters after his name as long as a bus, won the Nobel Prize in Physiology or Medicine in 2001, for his part in discovering how the cell cycle works. He was driven, he says, by the desire to understand what is the fundamental difference between life and death, and he realized the way to do it was to look at how cells divide.

Working with yeast, he figured out the genes and proteins involved in the regulation of cell division. He also showed that, in humans, these were the same genes, and that when the process goes wrong it can lead to cancer. He was knighted in 1999, he became president of Rockefeller University in New York, then president of the UK’s academy of sciences, the Royal Society, and is currently director of the Francis Crick Institute in London, the biggest biomedical lab in Europe. Once, when I was to introduce him at a science festival, I asked how I should refer to him, and he said “the blob” (obviously I ignored this instruction). He’s one of the most influential scientists of our time.

He also has an unusual family pedigree. Living in New York after winning his Nobel Prize, he decided to apply for a green card, but his application was rejected because the birth certificate he’d submitted was a short version, which didn’t show his parents’ names. When he retrieved the long form from the UK register office, he found that his father’s name was unknown, and under “mother’s name” was the name of the woman he’d always thought was his sister. Paul’s mother became pregnant by an unknown man and gave birth to Paul in Norfolk, to hide the illegitimacy. He was brought up by his maternal grandparents, who pretended to be his parents for the rest of their lives. The woman eighteen years his senior, who he thought was his sister but was actually his mother, had died by then. His “brothers” were his uncles. He never knew his birth father. If the story was in a soap opera, you wouldn’t believe it.

Before this intrigue came to light, Nurse was raised essentially as an only child, his purported siblings being so much older than he was. He spent a lot of time alone, and on the long walk to and from school an innate and powerful curiosity became apparent. Like Hilary Mantel, he cites curiosity as the central component of his intellect, although in Nurse’s case it is supplemented by logic and experimentation, and it is these things that make him a scientist.

I say innate curiosity, but Nurse, when I sit down with him at the Crick Institute, is careful not to assume that his curiosity is a genetic trait: “There’s no doubt that I somehow developed an almost unhealthy curiosity about the natural world around me, and it may have been because I wasn’t distracted by too many of the family things.” The time he spent alone made him observe nature. He became interested in astronomy and natural history and in trying to work out how the world worked, and that encouraged a real curiosity about the natural world. It’s a curiosity he still has.

He says that, on the whole, most of our higher-faculty characteristics, such as intelligence, come down to about 50 percent genetics and 50 percent environment, sometimes a little more or less. “As a geneticist, I’m fully aware of the impact genes can have. My environmental component was not academic and intellectual, so I have rationalized in my head how my environment was encouraging for where I ended up.” Before he discovered that no one knew who his father was, he’d sometimes wondered why he was the intellectual outlier in the family. He didn’t have books at home, or parents who encouraged reading or curiosity. But his self-starting curiosity latched on to the stars in the sky and the moths in the hedgerows on the walk to school. I’m reminded of what Robert Plomin said to me. After seeing what happens with twins and adopted children reared in unstimulating environments or sent to poor schools, Plomin knows that ability will out: “At the higher end of ability, you’d almost have to lock kids in closets to keep them from getting ahead.”

Scientists are supposed to pride themselves on their objectivity and adherence to logic and evidence, but in practice it’s all too easy for some to jump to conclusions and cling to a favored hypothesis based on less-than-watertight data. Nurse genuinely seems to embody the “proper” scientific method. He is brutal with ideas. “I’ve never felt that having clever ideas by itself is worth very much, because ideas are cheap. They’re only worth something when you test them to destruction.”

Nurse identifies the desire to test something to destruction as a component of intelligence. “There may be something to do with pride there. If I have an idea and have observations to support it, rather than get that out there, I go around and look at it in different ways and try and destroy it. And only if it survives do I begin to talk about it. So there’s something about destroying your own ideas. It means that when it does survive, you speak with great confidence.”

When Nurse arrived at grammar school, and then university, he was surrounded by students from more enriched backgrounds. Kids who’d had books at home, and intellectual encouragement. It made him feel he needed to learn about the world because other people knew much more. So he started reading the Times Literary Supplement and the London Review of Books, to keep his education broad, and he still does. “It might’ve been driven by feeling a bit inadequate, but it was more that there are many things out there in the world that I wanted to know about. So it’s back to this intense curiosity.”

His curiosity and desire to discover drew him to the life sciences. In the physical sciences, the questions seemed too big and difficult to address and he felt too small a cog. Whereas in biology, the problems are things you can observe. He would count spiderwebs in the back garden and wonder about the corresponding distribution of flies. “I couldn’t study the structure of the atom in my garden.”

I mention that he could do it in his head, but he says he wasn’t in his head, he was always observing and relating things to the world. The idea of internalizing problems and thinking about them mathematically was alien, completely outside what he’d been exposed to in his nonacademic family. It reminds me of what Hilary Mantel said, that when mathematics at school became conceptual, she stopped keeping up. She too was raised in a nonacademic family (“I was at the worst school in Derbyshire at the time”), although outside school she was immersed in books. And it reminds me of the psychology of “tilt”: Mantel’s language skills tilted her toward writing; Nurse’s curiosity about the natural world tilted him to biology.

Paul Nurse’s children, of course, have grown up in an academic, intellectual family. One of his daughters is a high-energy physicist. “She’s next generation on and was brought up in a different way and obviously wasn’t daunted by this, but I was,” he says.

At school, as throughout his life, Nurse was quite often “off piste”—prone to following imaginative leads, taking off on flights of fancy. “If I was off piste in an interesting way, my marks went up, and if not, they went down.” And as he grew more mature, going off piste become profitable. “I’m pretty imaginative when thinking about solutions, but I’m always being dragged back to experiment and observation and testing. Which may even have its roots in that I liked looking at the world.”

Mindful of some of the subjects I’ll be investigating—memory and languages—I mention that these are supposed to be things that intelligent people are good at, but he’s dumped them. “They’re related. You need to be able to remember that chien is dog,” he says. “But there’s another problem—my grandparents had strong Norfolk accents.” He puts on a country-bumpkin accent. “I was living in London where they made fun of me talking like this.”

His inability to pronounce words in a “normal” way (he means without a strong regional accent) hindered him when it came to languages, he says, and he’s no good at mimicking. His memory is a problem, but putting things together in unusual ways is a real strength. “It’s making connections from different parts of the intellectual universe that most people have trouble connecting. It’s being voracious across the board, but coupled with logic. I put things together and then apply logic, and if that fails, dismiss it.”

There is a family element to this, it seems. He came from a humble background, and doesn’t want anyone else kicking his ideas—perhaps then they would dismiss him as a bumpkin.

Nurse is sixty-eight now. Cognitive powers, especially speed of thinking and the ability to deduce things without prior knowledge, decline from your thirties, but crystallized intelligence—as we’ve seen, this is the sort you draw on when you need knowledge of the real world, facts and figures, experience—maintains its level for some decades.20 I ask Nurse what’s changed for him.

“I know I’m not such a good thinker as when I was thirty.”

One of the things that’s gone is the ability to concentrate for hours on something. “I saw this in my physics daughter: like a laser on a problem until it vaporizes. I think I’m too distractible now to get that complete focus.”

He can compensate to some extent. “The thought processes you apply to a problem, I’ve been through before so I know what to do.” Plus a form of cunning sometimes develops, which can help. His raw intellectual endeavor may be weaker, but Nurse has experience—some of which he imparts as I leave. First, the railway-track metaphor of ideas.

“When you have an idea to explain a phenomenon, it’s actually difficult to think of another idea, and you start to run down rails. You have to find ways to jump the tracks.”

So he has tricks that enable him to do this. Don’t work too hard. “If you’re constantly thinking of the problem, you’re on the same track.”

Read things that aren’t necessarily relevant, and do other things that force a change of tack. Nurse is a pilot, and flying forces his brain to switch tracks. “You think of nothing else while you’re up there other than staying alive. And when you come back down again, literally, after gliding in the Alps, you look at everything in a fresh way because you’ve cleared your brain out.”

Finally, he has an observation on failure. “You cannot help but fail. Failure happens all the time.” You have to accept this, learn from it, and, crucially, move on. He says a lot of his supervisory advice is about stopping people from getting depressed when they fail, and about helping them develop a psychological approach to cope with failure. You have to have motivation to succeed, but you have to make sure your motivation is solid. “If you want to be famous, you’re probably never going to be. There’re different motivations. Curiosity drives me.”