Tim Harford's Blog, page 42

Mr Spock is not as logical as he’d like to think

Mr Spock, Star Trek’s pointy-eared, nimble-eyebrowed Vulcan, is a beloved figure, especially as portrayed by the late Leonard Nimoy. He is a cultural touchstone for superior rationality. There’s just one problem: Spock is actually terrible at logic.

As Julia Galef explains in her new book on how to make better decisions, The Scout Mindset, Spock turns out to be highly illogical in more than one way. The most obvious is that Spock’s model of other minds is badly flawed.

For example, in an early episode, “The Galileo Seven”, Spock and his subordinates have crashed a small ship and face hostile aliens who kill one crew member. Spock decides to deter any further attacks by firing warning shots. The aliens respond not by retreating in fear, but by attacking in anger, killing another of the crew.

“Most illogical reaction,” comments Spock. “[When] we demonstrated our superior weapons, they should have fled . . . I’m not responsible for their unpredictability.”

“They were perfectly predictable,” rages Dr McCoy, “to anyone with feeling.”

Spock is not being rational here, but the problem is not that he lacks feeling, rather that he lacks the capacity to learn from experience. He should have noticed aggression is often met with aggression.

To a fan of rational inquiry, which Galef is, Spock’s portrayal is an infuriating smear. Spock, she says, is a “Straw Vulcan” — a caricature of rationality designed to make rationality look foolish. Perhaps so, but the reason that I winced when I rewatched the episode is not because he was a caricature, but because his error looked all too familiar.

“Rationality is an assumption I make about other people . . . Rationality is the best predictive assumption available . . . If irrational behaviour is random, its effects may average out.”

That’s not Spock. It’s David Friedman in Hidden Order: The Economics of Everyday Life offering a distinctly Spock-like justification for assuming rationality in others: you might as well because rationality gives a predictive toehold, while irrational behaviour is hopelessly unpredictable.

I recommend Hidden Order as a superb introduction to economic thinking. However, it shares the weakness of mainstream economic approaches in the 1990s, when the book was published. The most obvious rejoinder to Friedman’s argument is McCoy’s: “irrational” does not mean “unpredictable”. People may be irrational in perfectly predictable ways, and indeed they are. (Not for nothing is a popular behavioural science book titled Predictably Irrational.)

There is a value in assuming rational behaviour. It is simple to describe and analyse, and it has predictive power. As a tractable, one-size-fits-all model of human behaviour, it may be as good as we are going to get. But in specific cases it may help to bring in perspectives from psychology, from experimental data, or simply from judgment and experience.

“I’ve always said that if you want one unifying theory of economic behaviour, you won’t do better than the neoclassical [rational] model,” Richard Thaler told me back in 2014, a few years before winning the Nobel Memorial Prize for his work on more psychologically realistic economics. He added that while the rational-choice model might be the best available unified theory, it was also “not particularly good at describing actual decision-making”.

Spock, then, may not be a Straw Vulcan after all, but a dramatic portrayal of the mistakes economists have tended to make in insisting that we must assume everyone is rational.

There is another way that we economists might learn from observing Spock’s mistakes. He is a truly terrible forecaster. Galef, rather delightfully, has gone through the full catalogue of Star Trek, finding every occurrence she could of Spock making a prediction.

“[There’s] only a very slight chance [this plan] would work,” Spock tells Captain James T Kirk at one stage. The plan works. “Intercepting all three ships is an impossibility,” he warns Kirk during another adventure. Kirk intercepts all three ships. The chance of a daring escape? “Difficult to be precise, Captain. I should say approximately 7,824.7 to one.” They escape.

Other fictional characters have made similar remarks. C-3PO (Star Wars) and Dr Strange (Marvel) spring to mind. We cannot blame them; blame, instead, the writers.

Yet this sort of overconfident nonsense is common in real-world punditry. We seem to have an unslakable thirst for knowledge about the future. Sadly, knowledge about the future is not easy to acquire, so we satisfy ourselves with the pretence of knowledge.

If you can’t be accurate, at least sound self-assured. Spock does, every time. “My choice will be a logical one,” he upbraids a subordinate, shortly before making another fatal error, “arrived at through logical means.”

Well said. But his record is not so good. According to Galef’s tally, when Spock says something is “impossible” it happens 83 per cent of the time, and when he gives something more than a 99.5 per cent chance, it happens just 17 per cent of the time. (He does OK with his forecasts of “likely”.) This makes him a reliably contrarian indicator, as Kirk seems to have realised — just ask Spock for his opinion, then do the opposite.

Failing that, if you want to become a better forecaster, do what Galef did: look back at old forecasts and keep score.

Written for and first published in the Financial Times on 11 June 2021.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”.

“One of the most wonderful collections of stories that I have read in a long time… fascinating.”- Steve Levitt (Freakonomics)

“If you aren’t in love with stats before reading this book, you will be by the time you’re done.”- Caroline Criado Perez (Invisible Women)

I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

The power of curiosity, storytelling podcasts, and other matters

I was interviewed by the EdSurge podcast on the subject of curiosity and misinformation. “It’s never been easier to fool yourself,” I said (apparently). “It’s never been easier to put yourself into a bubble, into an echo chamber. But at the same time, it’s never been easier to get really high-quality help—to ask smart questions and to go deep.”

Meanwhile I have been reading some very fine books that are not out yet, including Rutherford & Fry’s Complete Guide to Absolutely Everything and Michael Brooks’s The Art of More. Both worth a pre-order, proper reviews to follow in due course.

I also read Alan Garner’s Boneland, the sequel-that-is-not-a-sequel to brilliant children’s fantasy stories The Weirdstone of Brisingamen and The Moon of Gomrath. I liked it, but it’s such a different book. (Mild spoilers: Colin is in his forties and appears to have lost his mind. He thinks that he used to have a twin, Susan, but he cannot remember. Colin also worries that his therapist is a witch. Do not expect all this to be resolved with an exciting fight with svarts and bodachs.)

Last week I recommended Malcolm Gladwell’s Revisionist History. This week, a shout out for Jill Lepore’s wise and wide-ranging The Last Archive (season two just finished, go binge) and Matthew Syed’s very clever Sideways podcast.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”. I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

How not to Groupthink

In his acid parliamentary testimony recently, Dominic Cummings, the prime minister’s former chief adviser, blamed a lot of different people and things for the UK’s failure to fight Covid-19 — including “groupthink”. Groupthink is unlikely to fight back. It already has a terrible reputation, not helped by its Orwellian ring, and the term is used so often that I begin to fear that we have groupthink about groupthink.

So let’s step back. Groupthink was made famous in a 1972 book by psychologist Irving Janis. He was fascinated by the Bay of Pigs fiasco in 1961, in which a group of perfectly intelligent people in John F Kennedy’s administration made a series of perfectly ridiculous decisions to support a botched coup in Cuba. How had that happened? How can groups of smart people do such stupid things?

An illuminating metaphor from Scott Page, author of The Difference, a book about the power of diversity, is that of the cognitive toolbox. A good toolbox is not the same thing as a toolbox full of good tools: two dozen top-quality hammers will not do the job. Instead, what’s needed is variety: a hammer, pliers, a saw, a choice of screwdrivers and more. This is obvious enough and, in principle, it should be obvious for decision-making too: a group needs a range of ideas, skills, experience and perspectives. Yet when you put three hammers on a hiring committee, they are likely to hire another hammer.

This “homophily” — hanging out with people like ourselves — is the original sin of group decision-making, and there is no mystery as to how it happens. But things get worse.

One problem, investigated by Cass Sunstein and Reid Hastie in their book Wiser, is that groups intensify existing biases. One study looked at group discussions about then-controversial topics (climate change, same-sex marriage, affirmative action) by groups in left-leaning Boulder, Colorado, and in right-leaning Colorado Springs. Each group contained six individuals with a range of views, but after discussing those views with each other, the Boulder groups bunched sharply to the left and the Colorado Springs groups bunched similarly to the right, becoming both more extreme and more uniform within the group. In some cases, the emergent view of the group was more extreme than the prior view of any single member.

One reason for this is that when surrounded with fellow travellers, people became more confident in their own views. They felt reassured by the support of others. Meanwhile, people with contrary views tended to stay silent. Few people enjoy being publicly outnumbered. As a result, a false consensus emerged, with potential dissenters censoring themselves and the rest of the group gaining a misplaced sense of unanimity.

The Colorado experiments studied polarisation, but this is not just a problem of polarisation. Groups tend to seek common ground on any subject from politics to the weather, a fact revealed by “hidden profile” psychology experiments. In such experiments, groups are given a task (for example, to choose the best candidate for a job) and each member of the group is given different pieces of information. One might hope that each individual would share everything they knew, but instead what tends to happen is that people focus, redundantly, on what everybody already knows, rather than unearthing facts known to only one individual. The result is a decision-making disaster.

These “hidden profile” studies point to the heart of the problem: group discussions aren’t just about sharing information and making wise decisions. They are about cohesion — or, at least, finding common ground to chat about. Reading Charlan Nemeth’s No! The Power of Disagreement In A World That Wants To Get Along, one theme is that while dissent leads to better, more robust decisions, it also leads to discomfort and even distress. Disagreement is valuable but agreement feels so much more comfortable.

There is no shortage of solutions to the problem of groupthink, but to list them is to understand why they are often overlooked. The first and simplest is to embrace decision-making processes that require disagreement: appoint a “devil’s advocate” whose job is to be a contrarian, or practise “red-teaming”, with an internal group whose task is to play the role of hostile actors (hackers, invaders or simply critics) and to find vulnerabilities. The evidence suggests that red-teaming works better than having a devil’s advocate, perhaps because dissent needs strength in numbers.

A more fundamental reform is to ensure that there is a real diversity of skills, experience and perspectives in the room: the screwdrivers and the saws as well as the hammers. This seems to be murderously hard. When it comes to social interaction, the aphorism is wrong: opposites do not attract. We unconsciously surround ourselves with like-minded people.

Indeed, the process is not always unconscious. Boris Johnson’s cabinet could have contained Greg Clark and Jeremy Hunt, the two senior Conservative backbenchers who chair the committees to which Dominic Cummings gave his evidence about groupthink. But it does not. Why? Because they disagree with him too often.

The right groups, with the right processes, can make excellent decisions. But most of us don’t join groups to make better decisions. We join them because we want to belong. Groupthink persists because groupthink feels good.

Written for and first published in the Financial Times on 4 June 2021.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”.

“One of the most wonderful collections of stories that I have read in a long time… fascinating.”- Steve Levitt (Freakonomics)

“If you aren’t in love with stats before reading this book, you will be by the time you’re done.”- Caroline Criado Perez (Invisible Women)

I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

Newsletter: Mathematical objects from spreadsheets to auctions

The Financial Times Magazine published my cover essay on the joys and sorrows of spreadsheets. It was great fun to write, and occasionally sobering, as I delved into the origins of Excel, the struggles of 14th century Italian merchants, the eradication of smallpox, and even quizzed Bill Gates about the 64K limit in the xls file format. (The piece will emerge on this website eventually.)

Katie Steckles and Peter Rowlett talked to me about my secret obsession, auctions and auction theory, on the Mathematical Objects podcast. Meanwhile Malcolm Gladwell’s Revisionist History podcast is back, and the new episode on Waymo is an absolute delight.

No book review this week, as I spent most of my reading time either on books that haven’t yet been published or that are now out of print… but the reliably-interesting Ben Ho has a book out about the economics of trust that is likely to be worth reading.

In conversation with Robin Ince – a reminder that I’m talking to the wonderful Robin Ince online on Monday 5th July – please sign up and join us!

Don’t blame GDP for a slow post-covid reopening

“As more of everyday life returns, we must not forget about the things that quietly, efficiently (perhaps almost without us noticing) offer some of the greatest benefits of all.”

Those were the words recently of Lord Sebastian Coe, twice an Olympic gold medallist and current president of World Athletics. Coe was focused on Parkruns, free weekly running events around the UK and indeed the world put on by the Parkrun charity. Although organised outdoor sports have been legal in England for many weeks now, Parkrun has been slower to be able to reopen for adults – the plan is to open on 26 June.

But Coe’s point holds more broadly: as the widely vaccinated UK continues to open up, there have been some curious discrepancies in what is possible and what is not. In recent days, for example, I attempted a number of steps towards normality. I went to a library. I went swimming. I went to a book signing.

It was great to be out and about, but the overall experience was far from a return to 2019. The book signing was done not at a book festival, but alone in a warehouse in Didcot, after overcoming considerable red tape. The swimming pool, lent out by a local school, had kept changing rooms closed as a precaution. I changed poolside under a towel, which was not a spectacle anyone wanted. The library desk was precious: social distancing means the library can’t come close to accommodating all the readers who want to be there.

I welcome these indignities and inconveniences if they help bridge the gap between our tragic winter and a summer of safety and freedom. But there was a striking disparity. While the library, warehouse and pool were in full plague mode, I also visited a bustling London restaurant with colleagues that was so normal as to be disorienting. Had I stepped into a time machine? The only sign that this was 2021 was that the staff wore masks.

So what explains the difference? Critics of economics might offer a simple answer: gross domestic product or GDP, the most common way in which we measure the size of our economy. Restaurants, being a commercial enterprise in which money changes hands, contribute directly to GDP. The other activities do not.

Fully reopening every desk in a library would in principle increase the value of educational services produced, but such a change is unlikely to register in our national accounts. Nor is a book signing, provided free of charge in the hope of drumming up business. And Parkrun is a charity whose financial footprint is minuscule relative to its presence as a national pastime.

In a speech in 1968, presidential hopeful Robert Kennedy pointed to what measures of economic growth leave out: “Too much and for too long, we seemed to have surrendered personal excellence and community values in the mere accumulation of material things. Our gross national product . . . counts air pollution and cigarette advertising, and ambulances to clear our highways of carnage . . . Yet the gross national product does not allow for the health of our children . . . the beauty of our poetry or the strength of our marriages.”

Noble sentiments and mostly true. But while Kennedy juxtaposes the loss of “personal excellence and community values” with the fact that GNP does not include “the beauty of our poetry”, he stops short of explicitly connecting the two. That is wise. It would be absurd to suggest that the cure for bad poetry and bad marriages is reform of the Office for National Statistics.

It’s easy to blame GDP, but this is not about GDP. All over the UK, people are responding to incentives. For a restaurant, reopening is a matter of survival, and (currently modest) Covid-19 risks will be tolerated. In contrast, the local school does not depend on income from amateur swimming clubs; Oxford university’s Bodleian Libraries, more than four centuries old, are in no imminent danger if they cannot increase capacity tomorrow. And the local authorities and landowners who provide the land on which Parkruns take place are in no great hurry.

If the Office for National Statistics suddenly decided that Parkruns were worth a few billion pounds of GDP, would that alter any of these local decisions? I fail to see how.

Even though some of the best things in life are free, it should hardly be a surprise that people can be cautious when accommodating a voluntary effort while moving mountains when their own jobs are on the line. Thanks to the UK’s successful vaccine rollout, I suspect libraries and swimming clubs and Parkruns will all catch up with restaurants soon.

But there is a broader lesson here about the nature of change. Campaigners attack GDP for distorting national priorities. It is indeed an imperfect measure of economic growth and it does not even pretend to be a measure of widespread flourishing. But GDP does not figure as highly in national priorities as people seem to think. Just think of the UK’s three major policy thrusts over the past decade: first austerity, then Brexit, and finally lockdowns. Whatever you think of these policies, none of them ever pretended to be about maximising GDP.

Looking ahead, the next great challenge is climate change. We won’t meet it by reformulating GDP. We’ll meet it by adopting policies and norms that change the behaviour of businesses, local governments and individuals. Such decisions are not made while poring over national accounts.

Written for and first published in the Financial Times on 28 May 2021.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”.

“One of the most wonderful collections of stories that I have read in a long time… fascinating.”- Steve Levitt (Freakonomics)

“If you aren’t in love with stats before reading this book, you will be by the time you’re done.”- Caroline Criado Perez (Invisible Women)

I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

How to make the world add up with Robin Ince, How to re-enter normality, and graphs of life and death

In Conversation with Robin Ince – I’ll be talking with the amazing comedian, book gourmand and evangelist for science and reason online at the How To Academy on Monday 5th July – do come along!

If you’ve devoured the amazing story of how Florence Nightingale launched a public health revolution with a pie chart (it’s in How To Make The World Add Up / The Data Detective) then you might well enjoy Hannah Fry’s bravura essay in The New Yorker on how data visualisation saves – or costs – lives.

I was so pleased to hear the brilliant economist Betsey Stevenson (a senior economic official in various roles in the Obama administration) recommend The Undercover Economist Strikes Back on the Ezra Klein show. She said, “I just recommend that book to everyone because he explains the macro economy in a way that is just a joyous romp through macroeconomics. So if you ever felt like you needed to learn some more macro and wanted to have a blast to doing it, Tim Harford is your guy.” Well, it’s hard not to blush with a recommendation like that but it was also what I was trying to do with the book. Hurrah!

Two new questions have gone live on the “Data Detective challenge” at the Good Judgement project – do have a go at forecasting if you dare. These questions are about the Delta variant…

Slate’s How To podcast invited me to contribute as an ‘expert’ to a discussion about how to overcome post-pandemic anxiety. The real expert, Debra Kaysen, taught me a lot and I found the whole conversation so interesting, moving and thought-provoking.

Intellectual property: Murderous? Sacrosanct? Or simply in need of an overhaul?

Everyone knows that intellectual property is sacrosanct, a reward for good deeds and an essential way of supporting creative endeavours. That, at least, was the response to journalist Matthew Yglesias when he suggested in March that copyright protection should be limited to 30 years, rather than 70 years after the death of the author. (I made a similar case myself in this column a few years ago.) The writer Neil Gaiman described that concept, with characteristic bite, as “enthusiasm . . . for removing income from elderly and disadvantaged authors”, and the twitterati agreed.

How strange, then, that the reaction was so different when the Biden administration surprised most of us with an expression of support for (maybe, someday) waiving Covid-19 vaccine patents. Thank goodness! Everyone knows that intellectual property is a murderous enabler of “vaccine apartheid” for which there can be no justification.

It seems that we approve of boundless intellectual property for nice people and no IP at all for scoundrels. That is not much of a policy. Once upon a time, monarchs would hand out monopolies to favourites, but a modern society cannot be handing out IP to whoever seems most sympathetic.

Long copyright benefits a few “elderly and disadvantaged authors”, but it mostly benefits the corporations who own a handful of truly profitable properties such as Mickey Mouse and Batman. And speaking of vaccines, biotechnology has its share of underpaid creatives; just read last week’s FT Weekend Magazine about Katalin Kariko’s years of thankless struggle working on mRNA technology.

So let’s start again. Why do we do this intellectual property thing? And is there a better way? The wonderful thing about ideas is that they can be freely copied, but the terrible thing about ideas is that they can be freely copied. Everyone can enjoy them, but the incentive to create them in the first place seems questionable.

IP tries to resolve the dilemma. It is a temporary monopoly, artificially created by the stroke of a pen. The “monopoly” is what rewards creators for their efforts. The “temporary” is what ensures that we can all eventually enjoy the benefits of new ideas at the lowest possible cost: there is no need for King Lear or the wheel to enjoy IP protection in the 21st century.

There is a broad logic to intellectual property, then. But the specifics can be questioned. For example, just how temporary is the monopoly? F Scott Fitzgerald published The Great Gatsby in 1925 and died in 1940. The work only entered the public domain in 2021, after several posthumous copyright extensions, none of which can have been much of an incentive for him to write more.

Then there is the question of what deserves protection. At the height of the dotcom boom, an economics professor, Alex Tabarrok, was taking a shower when he dreamed up the idea of using cell phones to scan barcodes in a store, compare prices and order the product online. Alas, someone else had beaten him to the patent office by mere months. The idea, once unthinkable, was by 1999 rather obvious. But why should society award 20 years of monopoly rights for the kind of idea that an amateur could dream up in the shower?

Tabarrok suggests — rightly — that a 20-year patent should be awarded only if the inventor can prove the idea was expensive to develop. Without that, a five-year patent should be sufficient reward — and, more importantly, sufficient incentive.

And what of the intellectual property waiver for Covid-19 vaccines? It all seems like a sideshow. It was not the promise of a patent that produced the astonishingly rapid results; governments spent money to accelerate the process beyond the pure market incentive. Operation Warp Speed alone spent $10bn on Moderna, Oxford/AstraZeneca, Johnson & Johnson and others — and governments should spend more; that sum is trivial compared with the benefits of these vaccines.

Just as the patent played a subsidiary role in encouraging the invention, it also plays a minor role in slowing the spread of that invention. We urgently need to produce more vaccines but the short-term constraints on that are available production lines and raw materials, while the medium-term constraints are non-patentable expertise — the ineffable know-how that comes with experience.

An IP waiver, or the threat of one, might expand production next year. Then again, it might not: without IP protection, vaccine manufacturers might guard their non-patentable know-how more jealously. If we are to produce the extra doses we need, we should focus on lifting every constraint. Perhaps patents fall into that category, but it seems more likely that they are a distraction from the expense of subsidising new factories and more doses for low-income countries.

We should spend that money willingly, both for moral and for self-interested reasons.

As for intellectual property, the system needs to change in a hundred ways, some of which require the weakening of intellectual property and the strengthening of other incentives such as prizes and targeted subsidies. When we think through those changes, we should spend less time looking for victims and villains in the creative sphere — and more time thinking about where new ideas come from, and how they can be nurtured.

Written for and first published in the Financial Times on 21 May 2021.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”.

“One of the most wonderful collections of stories that I have read in a long time… fascinating.”- Steve Levitt (Freakonomics)

“If you aren’t in love with stats before reading this book, you will be by the time you’re done.”- Caroline Criado Perez (Invisible Women)

I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

Fear, Scouting, and when can you trust a statistic?

The Data Detective meets The Scout Mindset – I had the pleasure of being interviewed by Julia Galef, author of The Scout Mindset and one of my very favourite interviewers, on the Rationally Speaking podcast. We go deep – enjoy!

Last minute notice, but in a couple of hours I’m talking to Gillian Tett about her excellent and thought-provoking new book Anthro-Vision.

Intriguing books on my pile, which I hope to read soon: The Musical Human (Michael Spitzer, a recent Radio 4 book of the week), Journey Beyond Fear (John Hagel, amazing endorsements), The Social Instinct (Nicola Rouhani, an evolutionary psychologist explains the origins and limits of cooperation), How To Think (Tom Chatfield, and thus guaranteed to be excellent).

When can you trust statistics? I made a short little fun film for the BBC, trying to boil down some ideas in How To Make The World Add Up to the zestiest, most concentrated form. Enjoy!

Three talks (come along!), the psychology of magic, and more prediction challenges

Three talks I’m busy in the coming days! Do consider buying a ticket to my event at the Rotman school this Wednesday (10pm UK time, 5pm EST) – a copy of The Data Detective is included in the ticket price and with the excellent Heski Bar-Isaac steering the conversation I expect we’ll go deep. Come along!

Alternatively, on Saturday 12 June I’m giving a talk to conclude the IEA’s “Think” conference. Registration details here.

Or if you prefer to hear me interviewing someone else , next week (Monday 14th) I’m talking to Gillian Tett about her excellent and thought-provoking new book Anthro-Vision.

When will the UK have fully vaccinated 80% of its adult population? A new superforecasting question is live – sign up and have a try!

Experiencing the Impossible – not sure I’ve yet recommended Gustav Kuhn’s book about the psychology of magic, Experiencing the Impossible, but it’s a fascinating read with plenty of good stuff about the history, practice and neuroscience of magic. Having chatted to a professional magician or two, not all of them see it Kuhn’s way, and I am not qualified to judge. But I did enjoy the book very much and learned a lot.

Sunday Times No 1 Business Bestseller. I’m delighted to report that not only is How To Make The World Add Up still on the Times paperback bestseller lists, it’s back at number one on the Sunday Times business bestseller lists. If you’ve picked up a copy and / or recommended it to others. thank you.

I’ve set up a storefront on Bookshop in the United States and the United Kingdom – have a look and see all my recommendations; Bookshop is set up to support local independent retailers.

Can you really change who you are?

Femi was 21 years old when he was pulled over for speeding in Colindale, London; the police charged him with a cannabis offence. It was one of several brushes with the law. But Femi changed. As Christian Jarrett writes in Be Who You Want, “Femi, or to use his full name, Anthony Oluwafemi Olaseni Joshua OBE, became an Olympic gold medallist and the two-time heavyweight boxing champion of the world, heralded as an impeccable role model of clean living and good manners.”

Katy Milkman begins her book, How To Change, with another sporting icon: tennis player Andre Agassi. Agassi’s crimes were to wear an earring and tie-dyed shirts to tournaments, swear on court and — a Wimbledon crown notwithstanding — seem to be more interested in sponsorship than living up to his prodigious potential. Like Joshua, Agassi sorted it out: he found a new coach, Brad Gilbert, and sharpened his game enough to win seven further grand slam titles and — like Joshua — an Olympic gold.

I have never aspired to win an Olympic medal, but I can certainly imagine being stronger, fitter, more successful or just different, so I was intrigued to see two new books about personal change, both boasting that they bring “the science”. Jarrett’s book presents a more radical view of change: can a neurotic person become resilient and confident? Can a cautious, conservative soul become curious and keen to explore new experiences? Can an introvert become an extrovert — and should they want to? Milkman, in contrast, is interested not in changing who you are, but “where you want to be”. She wants to help you get more exercise or spend less time arguing on Facebook and more time reading, say, the Financial Times.

Milkman’s aim seems easier: surely, people have a fixed personality, but anyone can learn to skip sugar in their coffee. Perhaps not. Jarrett makes a persuasive case that personality types are more malleable than we might think. He cites a 2016 study based on the 1947 Scottish Mental Survey, which found almost no correlation between the personality of participants at the age of 14 with their personalities when re-surveyed at the age of 77.

From the outside, that doesn’t seem surprising — of course pensioners and teenagers are different, even when the pensioner and the teenager are the same person. But from the inside, it’s hard to grasp the possibility that we might change over the years as we leave school, move house, acquire hobbies and friends, get jobs, become parents, and experience love and loss. Yet we do and we will.

Meanwhile, the sugar-in-the-coffee problem is harder than it first seems. While an introvert like me finds it hard to imagine becoming an extrovert, I find it very easy to imagine eating less chocolate, doing more exercise, losing a bit of fat and gaining a bit of muscle tone. But while that is indeed easy to imagine, it is not so easy to actually do it.

Nevertheless, hope springs eternal. And here are three tips I discerned from Jarrett’s and Milkman’s research.

First: pick your moment. Milkman notes that one of the most successful behaviour-change campaigns was “Back to Sleep”, which started in the US in 1994 and tried to persuade new parents to place their children to sleep on their backs, rather than on their stomachs, to reduce the risk of sudden infant death. The campaign was a huge success because new parents are a blank slate: they didn’t have any preconceptions and did whatever they were told. The pandemic has put most of us at that new-parent stage when it comes to our diets, our spending habits and our socialising. It is a good time to change. If you miss the fresh-start window, try New Year’s Day, the first day of spring or your birthday; they all help too.

Second: change the situation. We instinctively attribute differences between people to differences in their personality, when much of what governs our behaviour is the situation in which we find ourselves. We’re social beings: if you want to adopt a vegetarian diet, hang out with vegetarians and copy them; if you want to exercise, find an exercise buddy. (This can work against us, too: if you want to spend less money on take-out coffees, your biggest obstacle is the friend who likes seeing you at Starbucks.) Jarrett argues that this works for personality types, too. If you want to be less of an introvert, you’ll need to force yourself to take up an activity that requires social contact. Change your actions and your personality may change too.

Third: bundle temptations with virtuous activity. Milkman suggests listening to your favourite audiobook only while running, or allowing yourself to binge on Netflix only on an exercise bike.

But while both books offer a variety of sensible tips, it is interesting to observe what they don’t say. Jarrett says little about how bad-boy Femi became golden-boy Joshua. Milkman doesn’t mention that Agassi’s grand slams were punctuated by a fall out of the top 100, nor that he took crystal meth in 1997, failed a drug test and, according to his own 2009 autobiography, lied about it.

Stories of change are inspiring and straightforward, especially when the narrator knows that they end with an Olympic gold. Rewriting these stories from the inside is never so simple. But it can be done.

Written for and first published in the Financial Times on 14 May 2021.

The paperback of “How To Make The World Add Up” is now out. US title: “The Data Detective”.

“Nobody makes the statistics of everyday life more fascinating and enjoyable than Tim Harford.”- Bill Bryson

“This entertaining, engrossing book about the power of numbers, logic and genuine curiosity”- Maria Konnikova

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