The optimism bias | Tali Sharot

552,095 views ・ 2012-05-14

TED


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

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Translator: Timothy Covell Reviewer: Morton Bast
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I'm going to talk to you about optimism --
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or more precisely, the optimism bias.
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It's a cognitive illusion
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that we've been studying in my lab for the past few years,
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and 80 percent of us have it.
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It's our tendency to overestimate
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our likelihood of experiencing good events in our lives
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and underestimate our likelihood of experiencing bad events.
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So we underestimate our likelihood of suffering from cancer,
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being in a car accident.
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We overestimate our longevity, our career prospects.
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In short, we're more optimistic than realistic,
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but we are oblivious to the fact.
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Take marriage for example.
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In the Western world, divorce rates are about 40 percent.
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That means that out of five married couples,
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two will end up splitting their assets.
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But when you ask newlyweds about their own likelihood of divorce,
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they estimate it at zero percent.
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And even divorce lawyers, who should really know better,
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hugely underestimate their own likelihood of divorce.
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So it turns out that optimists are not less likely to divorce,
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but they are more likely to remarry.
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In the words of Samuel Johnson,
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"Remarriage is the triumph of hope over experience."
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(Laughter)
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So if we're married, we're more likely to have kids.
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And we all think our kids will be especially talented.
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This, by the way, is my two-year-old nephew, Guy.
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And I just want to make it absolutely clear
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that he's a really bad example of the optimism bias,
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because he is in fact uniquely talented.
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(Laughter)
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And I'm not alone.
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Out of four British people, three said
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that they were optimistic about the future of their own families.
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That's 75 percent.
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But only 30 percent said
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that they thought families in general
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are doing better than a few generations ago.
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And this is a really important point,
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because we're optimistic about ourselves,
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we're optimistic about our kids,
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we're optimistic about our families,
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but we're not so optimistic about the guy sitting next to us,
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and we're somewhat pessimistic
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about the fate of our fellow citizens and the fate of our country.
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But private optimism about our own personal future
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remains persistent.
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And it doesn't mean that we think things will magically turn out okay,
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but rather that we have the unique ability to make it so.
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Now I'm a scientist, I do experiments.
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So to show you what I mean,
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I'm going to do an experiment here with you.
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So I'm going to give you a list of abilities and characteristics,
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and I want you to think for each of these abilities
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where you stand relative to the rest of the population.
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The first one is getting along well with others.
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Who here believes they're at the bottom 25 percent?
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Okay, that's about 10 people out of 1,500.
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Who believes they're at the top 25 percent?
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That's most of us here.
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Okay, now do the same for your driving ability.
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How interesting are you?
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How attractive are you?
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How honest are you?
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And finally, how modest are you?
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So most of us put ourselves above average
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on most of these abilities.
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Now this is statistically impossible.
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We can't all be better than everyone else.
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(Laughter)
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But if we believe we're better than the other guy,
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well that means that we're more likely to get that promotion, to remain married,
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because we're more social, more interesting.
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And it's a global phenomenon.
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The optimism bias has been observed
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in many different countries --
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in Western cultures, in non-Western cultures,
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in females and males,
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in kids, in the elderly.
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It's quite widespread.
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But the question is, is it good for us?
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So some people say no.
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Some people say the secret to happiness
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is low expectations.
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I think the logic goes something like this:
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If we don't expect greatness,
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if we don't expect to find love and be healthy and successful,
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well we're not going to be disappointed when these things don't happen.
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And if we're not disappointed when good things don't happen,
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and we're pleasantly surprised when they do,
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we will be happy.
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So it's a very good theory,
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but it turns out to be wrong for three reasons.
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Number one: Whatever happens, whether you succeed or you fail,
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people with high expectations always feel better.
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Because how we feel when we get dumped or win employee of the month
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depends on how we interpret that event.
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The psychologists Margaret Marshall and John Brown
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studied students with high and low expectations.
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And they found that when people with high expectations succeed,
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they attribute that success to their own traits.
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"I'm a genius, therefore I got an A,
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therefore I'll get an A again and again in the future."
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When they failed, it wasn't because they were dumb,
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but because the exam just happened to be unfair.
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Next time they will do better.
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People with low expectations do the opposite.
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So when they failed it was because they were dumb,
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and when they succeeded
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it was because the exam just happened to be really easy.
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Next time reality would catch up with them.
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So they felt worse.
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Number two: Regardless of the outcome,
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the pure act of anticipation makes us happy.
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The behavioral economist George Lowenstein
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asked students in his university
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to imagine getting a passionate kiss from a celebrity, any celebrity.
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Then he said, "How much are you willing to pay
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to get a kiss from a celebrity
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if the kiss was delivered immediately,
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in three hours, in 24 hours, in three days,
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in one year, in 10 years?
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He found that the students were willing to pay the most
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not to get a kiss immediately,
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but to get a kiss in three days.
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They were willing to pay extra in order to wait.
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Now they weren't willing to wait a year or 10 years;
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no one wants an aging celebrity.
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But three days seemed to be the optimum amount.
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So why is that?
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Well if you get the kiss now, it's over and done with.
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But if you get the kiss in three days,
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well that's three days of jittery anticipation, the thrill of the wait.
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The students wanted that time
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to imagine where is it going to happen,
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how is it going to happen.
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Anticipation made them happy.
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This is, by the way, why people prefer Friday to Sunday.
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It's a really curious fact,
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because Friday is a day of work and Sunday is a day of pleasure,
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so you'd assume that people will prefer Sunday,
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but they don't.
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It's not because they really, really like being in the office
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and they can't stand strolling in the park
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or having a lazy brunch.
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We know that, because when you ask people
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about their ultimate favorite day of the week,
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surprise, surprise, Saturday comes in at first,
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then Friday, then Sunday.
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People prefer Friday
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because Friday brings with it the anticipation of the weekend ahead,
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all the plans that you have.
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On Sunday, the only thing you can look forward to
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is the work week.
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So optimists are people who expect more kisses in their future,
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more strolls in the park.
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And that anticipation enhances their wellbeing.
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In fact, without the optimism bias,
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we would all be slightly depressed.
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People with mild depression,
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they don't have a bias when they look into the future.
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They're actually more realistic than healthy individuals.
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But individuals with severe depression,
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they have a pessimistic bias.
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So they tend to expect the future
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to be worse than it ends up being.
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So optimism changes subjective reality.
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The way we expect the world to be changes the way we see it.
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But it also changes objective reality.
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It acts as a self-fulfilling prophecy.
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And that is the third reason
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why lowering your expectations will not make you happy.
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Controlled experiments have shown
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that optimism is not only related to success,
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it leads to success.
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Optimism leads to success in academia and sports and politics.
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And maybe the most surprising benefit of optimism is health.
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If we expect the future to be bright,
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stress and anxiety are reduced.
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So all in all, optimism has lots of benefits.
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But the question that was really confusing to me was,
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how do we maintain optimism in the face of reality?
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As an neuroscientist, this was especially confusing,
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because according to all the theories out there,
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when your expectations are not met, you should alter them.
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But this is not what we find.
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We asked people to come into our lab
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in order to try and figure out what was going on.
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We asked them to estimate their likelihood
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of experiencing different terrible events in their lives.
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So, for example, what is your likelihood of suffering from cancer?
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And then we told them the average likelihood
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of someone like them to suffer these misfortunes.
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So cancer, for example, is about 30 percent.
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And then we asked them again,
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"How likely are you to suffer from cancer?"
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What we wanted to know was
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whether people will take the information that we gave them
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to change their beliefs.
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And indeed they did --
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but mostly when the information we gave them
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was better than what they expected.
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So for example,
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if someone said, "My likelihood of suffering from cancer
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is about 50 percent,"
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and we said, "Hey, good news.
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The average likelihood is only 30 percent,"
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the next time around they would say,
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"Well maybe my likelihood is about 35 percent."
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So they learned quickly and efficiently.
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But if someone started off saying,
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"My average likelihood of suffering from cancer is about 10 percent,"
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and we said, "Hey, bad news.
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The average likelihood is about 30 percent,"
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the next time around they would say,
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"Yep. Still think it's about 11 percent."
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(Laughter)
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So it's not that they didn't learn at all -- they did --
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but much, much less than when we gave them
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positive information about the future.
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And it's not that they didn't remember the numbers that we gave them;
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everyone remembers that the average likelihood of cancer
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is about 30 percent
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and the average likelihood of divorce is about 40 percent.
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But they didn't think that those numbers were related to them.
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What this means is that warning signs such as these
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may only have limited impact.
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Yes, smoking kills, but mostly it kills the other guy.
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What I wanted to know was
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what was going on inside the human brain
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that prevented us from taking these warning signs personally.
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But at the same time,
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when we hear that the housing market is hopeful,
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we think, "Oh, my house is definitely going to double in price."
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To try and figure that out,
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I asked the participants in the experiment
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to lie in a brain imaging scanner.
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It looks like this.
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And using a method called functional MRI,
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we were able to identify regions in the brain
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that were responding to positive information.
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One of these regions is called the left inferior frontal gyrus.
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So if someone said, "My likelihood of suffering from cancer is 50 percent,"
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and we said, "Hey, good news.
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Average likelihood is 30 percent,"
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the left inferior frontal gyrus would respond fiercely.
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And it didn't matter if you're an extreme optimist, a mild optimist
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or slightly pessimistic,
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everyone's left inferior frontal gyrus
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was functioning perfectly well,
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whether you're Barack Obama or Woody Allen.
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On the other side of the brain,
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the right inferior frontal gyrus was responding to bad news.
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And here's the thing: it wasn't doing a very good job.
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The more optimistic you were,
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the less likely this region was
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to respond to unexpected negative information.
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And if your brain is failing
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at integrating bad news about the future,
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you will constantly leave your rose-tinted spectacles on.
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So we wanted to know, could we change this?
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Could we alter people's optimism bias
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by interfering with the brain activity in these regions?
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And there's a way for us to do that.
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This is my collaborator Ryota Kanai.
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And what he's doing is he's passing a small magnetic pulse
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through the skull of the participant in our study
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into their inferior frontal gyrus.
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And by doing that,
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he's interfering with the activity of this brain region
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for about half an hour.
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After that everything goes back to normal, I assure you.
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(Laughter)
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So let's see what happens.
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First of all, I'm going to show you
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the average amount of bias that we see.
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So if I was to test all of you now,
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this is the amount that you would learn
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more from good news relative to bad news.
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Now we interfere with the region
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that we found to integrate negative information in this task,
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and the optimism bias grew even larger.
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We made people more biased in the way that they process information.
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Then we interfered with the brain region
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that we found to integrate good news in this task,
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and the optimism bias disappeared.
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We were quite amazed by these results
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because we were able to eliminate
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a deep-rooted bias in humans.
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And at this point we stopped and we asked ourselves,
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would we want to shatter the optimism illusion into tiny little bits?
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If we could do that, would we want to take people's optimism bias away?
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Well I've already told you about all of the benefits of the optimism bias,
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which probably makes you want to hold onto it for dear life.
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But there are, of course, pitfalls,
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and it would be really foolish of us to ignore them.
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Take for example this email I recieved
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from a firefighter here in California.
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He says, "Fatality investigations for firefighters
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often include 'We didn't think the fire was going to do that,'
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even when all of the available information
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was there to make safe decisions."
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This captain is going to use our findings on the optimism bias
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to try to explain to the firefighters
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why they think the way they do,
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to make them acutely aware of this very optimistic bias in humans.
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So unrealistic optimism can lead to risky behavior,
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to financial collapse, to faulty planning.
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The British government, for example,
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has acknowledged that the optimism bias
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can make individuals more likely
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to underestimate the costs and durations of projects.
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So they have adjusted the 2012 Olympic budget
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for the optimism bias.
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My friend who's getting married in a few weeks
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has done the same for his wedding budget.
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And by the way, when I asked him about his own likelihood of divorce,
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he said he was quite sure it was zero percent.
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So what we would really like to do,
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is we would like to protect ourselves from the dangers of optimism,
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but at the same time remain hopeful,
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benefiting from the many fruits of optimism.
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And I believe there's a way for us to do that.
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The key here really is knowledge.
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We're not born with an innate understanding of our biases.
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These have to be identified by scientific investigation.
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But the good news is that becoming aware of the optimism bias
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does not shatter the illusion.
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It's like visual illusions,
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in which understanding them does not make them go away.
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And this is good because it means
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we should be able to strike a balance,
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to come up with plans and rules
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to protect ourselves from unrealistic optimism,
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but at the same time remain hopeful.
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I think this cartoon portrays it nicely.
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Because if you're one of these pessimistic penguins up there
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who just does not believe they can fly,
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you certainly never will.
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Because to make any kind of progress,
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we need to be able to imagine a different reality,
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and then we need to believe that that reality is possible.
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But if you are an extreme optimistic penguin
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who just jumps down blindly hoping for the best,
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you might find yourself in a bit of a mess when you hit the ground.
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But if you're an optimistic penguin
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who believes they can fly,
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but then adjusts a parachute to your back
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just in case things don't work out exactly as you had planned,
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you will soar like an eagle,
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even if you're just a penguin.
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Thank you.
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(Applause)
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Original video on YouTube.com
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