Tim Harford: Trial, error and the God complex

341,761 views ・ 2011-07-15

TED


Please double-click on the English subtitles below to play the video.

00:15
It's the Second World War.
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A German prison camp.
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And this man,
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Archie Cochrane,
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is a prisoner of war and a doctor,
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and he has a problem.
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The problem is that the men under his care
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are suffering
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from an excruciating and debilitating condition
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that Archie doesn't really understand.
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The symptoms
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are this horrible swelling up of fluids under the skin.
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But he doesn't know whether it's an infection, whether it's to do with malnutrition.
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He doesn't know how to cure it.
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And he's operating in a hostile environment.
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And people do terrible things in wars.
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The German camp guards, they've got bored.
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They've taken to just firing into the prison camp at random
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for fun.
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On one particular occasion,
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one of the guards threw a grenade into the prisoners' lavatory
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while it was full of prisoners.
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He said he heard suspicious laughter.
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And Archie Cochrane, as the camp doctor,
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was one of the first men in
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to clear up the mess.
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And one more thing:
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Archie was suffering from this illness himself.
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So the situation seemed pretty desperate.
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But Archie Cochrane
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was a resourceful person.
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He'd already smuggled vitamin C into the camp,
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and now he managed
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to get hold of supplies of marmite
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on the black market.
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Now some of you will be wondering what marmite is.
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Marmite is a breakfast spread beloved of the British.
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It looks like crude oil.
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It tastes ...
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zesty.
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And importantly,
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it's a rich source
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of vitamin B12.
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So Archie splits the men under his care as best he can
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into two equal groups.
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He gives half of them vitamin C.
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He gives half of them vitamin B12.
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He very carefully and meticulously notes his results
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in an exercise book.
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And after just a few days,
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it becomes clear
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that whatever is causing this illness,
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marmite is the cure.
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So Cochrane then goes to the Germans who are running the prison camp.
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Now you've got to imagine at the moment --
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forget this photo, imagine this guy
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with this long ginger beard and this shock of red hair.
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He hasn't been able to shave -- a sort of Billy Connolly figure.
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Cochrane, he starts ranting at these Germans
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in this Scottish accent --
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in fluent German, by the way, but in a Scottish accent --
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and explains to them how German culture was the culture
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that gave Schiller and Goethe to the world.
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And he can't understand
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how this barbarism can be tolerated,
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and he vents his frustrations.
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And then he goes back to his quarters,
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breaks down and weeps
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because he's convinced that the situation is hopeless.
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But a young German doctor
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picks up Archie Cochrane's exercise book
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and says to his colleagues,
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"This evidence is incontrovertible.
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If we don't supply vitamins to the prisoners,
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it's a war crime."
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And the next morning,
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supplies of vitamin B12 are delivered to the camp,
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and the prisoners begin to recover.
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03:39
Now I'm not telling you this story
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because I think Archie Cochrane is a dude,
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although Archie Cochrane is a dude.
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I'm not even telling you the story
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because I think we should be running
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more carefully controlled randomized trials
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in all aspects of public policy,
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although I think that would also be completely awesome.
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I'm telling you this story
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because Archie Cochrane, all his life,
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fought against a terrible affliction,
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and he realized it was debilitating to individuals
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and it was corrosive to societies.
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And he had a name for it.
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He called it the God complex.
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Now I can describe the symptoms of the God complex very, very easily.
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So the symptoms of the complex
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are, no matter how complicated the problem,
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you have an absolutely overwhelming belief
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that you are infallibly right in your solution.
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Now Archie was a doctor,
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so he hung around with doctors a lot.
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And doctors suffer from the God complex a lot.
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Now I'm an economist, I'm not a doctor,
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but I see the God complex around me all the time
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in my fellow economists.
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I see it in our business leaders.
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I see it in the politicians we vote for --
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people who, in the face of an incredibly complicated world,
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are nevertheless absolutely convinced
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that they understand the way that the world works.
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And you know, with the future billions that we've been hearing about,
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the world is simply far too complex
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to understand in that way.
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Well let me give you an example.
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Imagine for a moment
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that, instead of Tim Harford in front of you,
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there was Hans Rosling presenting his graphs.
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You know Hans:
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the Mick Jagger of TED.
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(Laughter)
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And he'd be showing you these amazing statistics,
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these amazing animations.
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And they are brilliant; it's wonderful work.
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But a typical Hans Rosling graph:
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think for a moment, not what it shows,
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but think instead about what it leaves out.
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So it'll show you GDP per capita,
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population, longevity,
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that's about it.
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So three pieces of data for each country --
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three pieces of data.
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Three pieces of data is nothing.
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I mean, have a look at this graph.
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This is produced by the physicist Cesar Hidalgo.
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He's at MIT.
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Now you won't be able to understand a word of it,
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but this is what it looks like.
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Cesar has trolled the database
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of over 5,000 different products,
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and he's used techniques of network analysis
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to interrogate this database
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and to graph relationships between the different products.
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And it's wonderful, wonderful work.
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You show all these interconnections, all these interrelations.
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And I think it'll be profoundly useful
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in understanding how it is that economies grow.
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Brilliant work.
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Cesar and I tried to write a piece for The New York Times Magazine
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explaining how this works.
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And what we learned
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is Cesar's work is far too good to explain
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in The New York Times Magazine.
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Five thousand products --
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that's still nothing.
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Five thousand products --
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imagine counting every product category
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in Cesar Hidalgo's data.
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Imagine you had one second
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per product category.
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In about the length of this session,
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you would have counted all 5,000.
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Now imagine doing the same thing
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for every different type of product on sale in Walmart.
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There are 100,000 there. It would take you all day.
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Now imagine trying to count
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every different specific product and service
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on sale in a major economy
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such as Tokyo, London or New York.
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It's even more difficult in Edinburgh
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because you have to count all the whisky and the tartan.
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If you wanted to count every product and service
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on offer in New York --
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there are 10 billion of them --
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it would take you 317 years.
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This is how complex the economy we've created is.
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And I'm just counting toasters here.
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I'm not trying to solve the Middle East problem.
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The complexity here is unbelievable.
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And just a piece of context --
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the societies in which our brains evolved
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had about 300 products and services.
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You could count them in five minutes.
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So this is the complexity of the world that surrounds us.
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This perhaps is why
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we find the God complex so tempting.
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We tend to retreat and say, "We can draw a picture,
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we can post some graphs,
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we get it, we understand how this works."
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And we don't.
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We never do.
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Now I'm not trying to deliver a nihilistic message here.
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I'm not trying to say we can't solve
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complicated problems in a complicated world.
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We clearly can.
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But the way we solve them
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is with humility --
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to abandon the God complex
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and to actually use a problem-solving technique that works.
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And we have a problem-solving technique that works.
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Now you show me
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a successful complex system,
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and I will show you a system
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that has evolved through trial and error.
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Here's an example.
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This baby was produced through trial and error.
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I realize that's an ambiguous statement.
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Maybe I should clarify it.
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This baby is a human body: it evolved.
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What is evolution?
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Over millions of years, variation and selection,
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variation and selection --
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trial and error,
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trial and error.
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And it's not just biological systems
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that produce miracles through trial and error.
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You could use it in an industrial context.
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So let's say you wanted to make detergent.
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Let's say you're Unilever
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and you want to make detergent in a factory near Liverpool.
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How do you do it?
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Well you have this great big tank full of liquid detergent.
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You pump it at a high pressure through a nozzle.
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You create a spray of detergent.
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Then the spray dries. It turns into powder.
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It falls to the floor.
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You scoop it up. You put it in cardboard boxes.
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You sell it at a supermarket.
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You make lots of money.
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How do you design that nozzle?
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It turns out to be very important.
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Now if you ascribe to the God complex,
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what you do is you find yourself a little God.
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You find yourself a mathematician; you find yourself a physicist --
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somebody who understands the dynamics of this fluid.
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And he will, or she will,
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calculate the optimal design of the nozzle.
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Now Unilever did this and it didn't work --
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too complicated.
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Even this problem, too complicated.
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But the geneticist Professor Steve Jones
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describes how Unilever actually did solve this problem --
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trial and error,
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variation and selection.
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You take a nozzle
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and you create 10 random variations on the nozzle.
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You try out all 10; you keep the one that works best.
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You create 10 variations on that one.
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You try out all 10. You keep the one that works best.
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You try out 10 variations on that one.
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You see how this works, right?
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And after 45 generations,
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you have this incredible nozzle.
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It looks a bit like a chess piece --
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functions absolutely brilliantly.
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We have no idea
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why it works,
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no idea at all.
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And the moment you step back from the God complex --
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let's just try to have a bunch of stuff;
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let's have a systematic way of determining what's working and what's not --
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you can solve your problem.
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Now this process of trial and error
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is actually far more common in successful institutions
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than we care to recognize.
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And we've heard a lot about how economies function.
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The U.S. economy is still the world's greatest economy.
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How did it become the world's greatest economy?
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I could give you all kinds of facts and figures
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about the U.S. economy,
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but I think the most salient one is this:
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ten percent of American businesses
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disappear every year.
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That is a huge failure rate.
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It's far higher than the failure rate of, say, Americans.
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Ten percent of Americans don't disappear every year.
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Which leads us to conclude
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American businesses fail faster than Americans,
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and therefore American businesses are evolving faster than Americans.
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And eventually, they'll have evolved to such a high peak of perfection
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that they will make us all their pets --
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(Laughter)
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if, of course, they haven't already done so.
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I sometimes wonder.
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But it's this process of trial and error
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that explains this great divergence,
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this incredible performance of Western economies.
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It didn't come because you put some incredibly smart person in charge.
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It's come through trial and error.
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Now I've been sort of banging on about this
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for the last couple of months,
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and people sometimes say to me,
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"Well Tim, it's kind of obvious.
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Obviously trial and error is very important.
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Obviously experimentation is very important.
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Now why are you just wandering around saying this obvious thing?"
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So I say, okay, fine.
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You think it's obvious?
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I will admit it's obvious
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when schools
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start teaching children
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that there are some problems that don't have a correct answer.
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Stop giving them lists of questions
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every single one of which has an answer.
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And there's an authority figure in the corner
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behind the teacher's desk who knows all the answers.
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And if you can't find the answers,
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you must be lazy or stupid.
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When schools stop doing that all the time,
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I will admit that, yes,
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it's obvious that trial and error is a good thing.
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When a politician stands up
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campaigning for elected office
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and says, "I want to fix our health system.
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I want to fix our education system.
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I have no idea how to do it.
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I have half a dozen ideas.
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We're going to test them out. They'll probably all fail.
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Then we'll test some other ideas out.
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We'll find some that work. We'll build on those.
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We'll get rid of the ones that don't." --
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when a politician campaigns on that platform,
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and more importantly, when voters like you and me
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are willing to vote for that kind of politician,
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then I will admit
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that it is obvious that trial and error works, and that -- thank you.
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(Applause)
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Until then, until then
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I'm going to keep banging on about trial and error
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and why we should abandon the God complex.
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Because it's so hard
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to admit our own fallibility.
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It's so uncomfortable.
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And Archie Cochrane understood this as well as anybody.
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There's this one trial he ran
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many years after World War II.
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He wanted to test out
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the question of, where is it
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that patients should recover
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from heart attacks?
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Should they recover in a specialized cardiac unit in hospital,
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or should they recover at home?
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All the cardiac doctors tried to shut him down.
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They had the God complex in spades.
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They knew that their hospitals were the right place for patients,
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and they knew it was very unethical
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to run any kind of trial or experiment.
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Nevertheless, Archie managed to get permission to do this.
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He ran his trial.
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And after the trial had been running for a little while,
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he gathered together all his colleagues
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around his table,
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and he said, "Well, gentlemen,
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we have some preliminary results.
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They're not statistically significant.
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But we have something.
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And it turns out that you're right and I'm wrong.
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It is dangerous for patients
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to recover from heart attacks at home.
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They should be in hospital."
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And there's this uproar, and all the doctors start pounding the table
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and saying, "We always said you were unethical, Archie.
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You're killing people with your clinical trials. You need to shut it down now.
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Shut it down at once."
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And there's this huge hubbub.
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Archie lets it die down.
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And then he says, "Well that's very interesting, gentlemen,
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because when I gave you the table of results,
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I swapped the two columns around.
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It turns out your hospitals are killing people,
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and they should be at home.
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Would you like to close down the trial now,
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or should we wait until we have robust results?"
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Tumbleweed
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rolls through the meeting room.
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But Cochrane would do that kind of thing.
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And the reason he would do that kind of thing
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is because he understood
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it feels so much better
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to stand there and say,
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"Here in my own little world,
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I am a god, I understand everything.
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I do not want to have my opinions challenged.
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I do not want to have my conclusions tested."
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It feels so much more comfortable
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simply to lay down the law.
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Cochrane understood
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that uncertainty, that fallibility,
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that being challenged, they hurt.
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And you sometimes need to be shocked out of that.
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Now I'm not going to pretend that this is easy.
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It isn't easy.
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It's incredibly painful.
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And since I started talking about this subject
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and researching this subject,
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I've been really haunted by something
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a Japanese mathematician said on the subject.
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So shortly after the war,
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this young man, Yutaka Taniyama,
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developed this amazing conjecture
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called the Taniyama-Shimura Conjecture.
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It turned out to be absolutely instrumental
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many decades later
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in proving Fermat's Last Theorem.
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In fact, it turns out it's equivalent
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to proving Fermat's Last Theorem.
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You prove one, you prove the other.
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But it was always a conjecture.
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Taniyama tried and tried and tried
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and he could never prove that it was true.
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And shortly before his 30th birthday in 1958,
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Yutaka Taniyama killed himself.
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His friend, Goro Shimura --
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who worked on the mathematics with him --
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many decades later, reflected on Taniyama's life.
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He said,
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"He was not a very careful person
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as a mathematician.
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He made a lot of mistakes.
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But he made mistakes in a good direction.
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I tried to emulate him,
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but I realized
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it is very difficult
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to make good mistakes."
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Thank you.
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(Applause)
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