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  • I'm going to talk to you about optimism -- or more precisely

    翻訳: Shuichi Sakai 校正: Shinji Nakagawa

  • the optimism bias. It's a cognitive illusion that we've been studying in my lab for the past few years

    これから楽観主義についてお話します

  • and 80 percent of us have it.

    より正確に言うと 楽観主義バイアスについてです

  • It's our tendency to overestimate our likelihood of experiencing good events in our lives

    それは認知的錯覚の一種で

  • and underestimate our likelihood of experiencing bad events

    私たちの研究室で ここ数年間 研究してきましたが

  • So we underestimate our likelihood of suffering from cancer, being in a car accident

    80% の人がこのバイアスを持っています

  • We overestimate our longevity, our career prospects.

    私たちは 好ましい出来事が起きる確率を 過大評価し

  • In short, we're more optimistic than realistic, but we are oblivious to the fact.

    好ましくない出来事が起きる確率を

  • Take marriage for example. In the Western world, divorce rates are about 40 percent.

    過小評価する傾向にあります

  • That means that out of five married couples, two will end up splitting their assets

    例えばガンを患う確率だとか

  • But when you ask newlyweds about their own likelihood of divorce, they estimate it at zero percent

    交通事故に遭う確率を 過小評価します

  • And even divorce lawyers, who should really know better

    逆に 長寿やキャリア上の成功の可能性は 過大評価します

  • hugely underestimate their own likelihood of divorce.

    すなわち 私たちは 現実的というよりも楽観的なのですが

  • So it turns out that optimists are not less likely to divorce

    このことに気付いていません

  • but they are more likely to remarry.

    例えば 結婚を例にとりましょう

  • In the words of Samuel Johnson, "Remarriage is the triumph of hope over experience."

    西洋では 離婚率は約40%です

  • So if we're married, we're more likely to have kids.

    つまり 5組の夫婦の内

  • And we all think our kids will be especially talented.

    2組は財産分与を行うことになるということです

  • This, by the way, is my two-year-old nephew, Guy

    しかし 新婚さん達に 自分たちの離婚の可能性を問うと

  • And I just want to make it absolutely clear that he's a really bad example of the optimism bias

    0%だと推定します

  • because he is in fact uniquely talented.

    現実を知っている筈の 離婚専門の弁護士でさえ

  • And I'm not alone. Out of four British people,

    自分たちが離婚することになる確率を かなり過小評価します

  • three said that they were optimistic about the future of their own families. That's 75 percent.

    楽観主義者の離婚率は特に低くはない一方

  • But only 30 percent said that they thought families in general are doing better than a few generations ago.

    再婚率は高いことが分かっています

  • And this is a really important point, because we're optimistic about ourselves

    サミュエル・ジョンソンの言葉を借りると

  • we're optimistic about our kids, we're optimistic about our families

    『再婚とは 経験に対する希望の勝利である』 ということでしょう

  • but we're not so optimistic about the guy sitting next to us,

    (笑い)

  • and we're somewhat pessimistic about the fate of our fellow citizens and the fate of our country

    結婚していれば 子供を持つ可能性も高くなりますね

  • But private optimism about our own personal future remains persistent.

    そして皆 自分の子供には特に才能があると思っています

  • And it doesn't mean that we think things will magically turn out okay

    これは2歳の甥のガイですが

  • but rather that we have the unique ability to make it so.

    誤解がないように 明らかにしておきたいのですが

  • Now I'm a scientist, I do experiments. So to show you what I mean

    彼は楽観主義バイアスとしては例外中の例外です

  • I'm going to do an experiment here with you. Okay.

    だって特別に才能があるんですよ

  • So I'm going to give you a list of abilities and characteristics,

    (笑い)

  • and I want you to think for each of these abilities where you stand relative to the rest of the population.

    そして私に限ったことではありません

  • The first one is getting along well with others. Who here believes they're at the bottom 25 percent?

    英国人の4人に3人は

  • Okay, that's about 10 people out of 1,500. Who believes they're at the top 25 percent?

    自分たちの家族の将来は明るいと答えています

  • That's most of us here. Okay, now do the same for your driving ability.

    75%ですよ

  • How interesting are you? How attractive are you?

    しかし 一般的な家庭が

  • How honest are you? And finally, how modest are you?

    数世代前に比べて豊かになったと答えたのは

  • So most of us put ourselves above average on most of these abilities.

    たった30%でした

  • Now this is statistically impossible. We can't all be better than everyone else.

    これは重要なポイントです

  • But if we believe we're better than the other guy,

    私たちは自分自身ついては楽観的です

  • well that means that we're more likely to get that promotion, to remain married,

    自分の子供たちについても然り

  • because we're more social, more interesting.

    自分の家族についても然りです

  • And it's a global phenomenon. The optimism bias has been observed in many different countries

    しかし 隣に座っている他人に関しては楽観的ではなく

  • in Western cultures, in non-Western cultures

    他の市民や国の将来についても

  • in females and males, in kids, in the elderly. It's quite widespread.

    どちらかというと悲観的です

  • But the question is, is it good for us? So some people say no

    にもかかわらず 自分自身の将来に対する楽観主義は

  • Some people say the secret to happiness is low expectations

    根強く 揺らぎません

  • I think the logic goes something like this: If we don't expect greatness,

    それも 魔法によって良い結果がもたらせられると 思っている訳ではなく

  • if we don't expect to find love and be healthy and successful,

    自分たちにその結果を生み出す能力が 備わっていると思っているのです

  • well we're not going to be disappointed when these things don't happen.

    私は科学者なので 実験をしてみましょう

  • And if we're not disappointed when good things don't happen, and we're pleasantly surprised when they do, we will be happy.

    私が主張していることを説明するために

  • So it's a very good theory, but it turns out to be wrong for three reasons

    皆さんと一緒に 実験をしてみましょう

  • Number one: Whatever happens, whether you succeed or you fail, people with high expectations always feel better.

    能力や特徴を いくつかリストアップしますので

  • Because how we feel when we get dumped or win employee of the month depends on how we interpret that event.

    みなさん ひとつひとつの能力に関して

  • The psychologists Margaret Marshall and John Brown studied students with high and low expectations.

    人口全体と比較して どの程度の レベルかを考えてください

  • And they found that when people with high expectations succeed, they attribute that success to their own traits.

    まずは「社交性」です

  • I'm a genius, therefore I got an A, therefore I'll get an A again and again in the future

    社交性が下位25%だと思う人は 手をあげてください

  • When they failed, it wasn't because they were dumb, but because the exam just happened to be unfair.

    そうですね 1,500人中10人というところでしょうか

  • Next time they will do better. People with low expectations do the opposite.

    上位25%だと思う人は?

  • So when they failed it was because they were dumb

    ほとんど全員ですね

  • and when they succeeded it was because the exam just happened to be really easy. Next time reality would catch up with them. So they felt worse.

    同じように 運転のスキルについて考えてください

  • Number two: Regardless of the outcome, the pure act of anticipation makes us happy.

    自分がどれくらい面白いか?

  • The behavioral economist George Lowenstein asked students in his university to imagine getting a passionate kiss from a celebrity

    どれくらい魅力的か?

  • any celebrity.

    どれくらい正直か?

  • Then he said, "How much are you willing to pay to get a kiss from a celebrity if the kiss was delivered immediately

    最後に どれくらい謙虚か?

  • in three hours, in 24 hours, in three days, in one year, in 10 years?

    私たちのほとんどは これらの能力について

  • He found that the students were willing to pay the most not to get a kiss immediately, but to get a kiss in three days

    平均より上に自分を位置づけます

  • they were willing to pay extra in order to wait

    統計学的にはありえませんね

  • Now they weren't willing to wait a year or 10 years; no one wants an aging celebrity

    全員が全員より能力が高いというのは無理なのですから

  • But three days seemed to be the optimum amount.

    (笑い)

  • So why is that? Well if you get the kiss now, it's over and done with

    しかし隣の誰かと比べて 優位だと信じていれば

  • But if you get the kiss in three days, well that's three days of jittery anticipation, the thrill of the wait.

    仕事や結婚で成功する可能性は高くなります

  • The students wanted that time to imagine where is it going to happen, how is it going to happen.

    他の人よりも社交的で面白いのですから

  • Anticipation made them happy.

    これは世界共通の現象です

  • This is, by the way, why people prefer Friday to Sunday

    この楽観主義バイアスは 幅広く確認されています

  • It's a really curious fact, because Friday is a day of work and Sunday is a day of pleasure,

    多くの異なる国々で

  • so you'd assume that people will prefer Sunday, but they don't.

    西洋文化、非西洋文化ともに

  • It's not because they really, really like being in the office and they can't stand strolling in the park or having a lazy brunch.

    男女ともに

  • We know that, because when you ask people about their ultimate favorite day of the week,

    子供からお年寄りに至るまで

  • surprise, surprise, Saturday comes in at first, then Friday, then Sunday. People prefer Friday because Friday brings with it the anticipation of the weekend ahead

    とても普遍的です

  • all the plans that you have. On Sunday, the only thing you can look forward to is the work week.

    これが私たちにとって良いことなのでしょうか?

  • So optimists are people who expect more kisses in their future, more strolls in the park.

    「ノー」という人もいます

  • And that anticipation enhances their wellbeing

    幸福の秘訣は

  • In fact, without the optimism bias, we would all be slightly depressed. People with mild depression, they don't have a bias when they look into the future

    低い期待を持つことだ と唱える人もいます

  • They're actually more realistic than healthy individuals.

    彼らの論理はこんな感じです

  • But individuals with severe depression, they have a pessimistic bias.

    多くを期待しなければ

  • So they tend to expect the future to be worse than it ends up being.

    愛と健康と成功が 手に入ると期待しなければ

  • So optimism changes subjective reality. The way we expect the world to be changes the way we see it.

    手に入らなかった時に 落胆せずに済みます

  • But it also changes objective reality. It acts as a self-fulfilling prophecy.

    良い事が起きなかったときには 落胆せず

  • . And that is the third reason why lowering your expectations will not make you happy.

    良い事が起きた時には 驚き喜べば

  • Controlled experiments have shown that optimism is not only related to success

    幸せになれる という考え方です

  • it leads to success. Optimism leads to success in academia and sports and politics.

    なかなか良い理論に聞こえますが

  • And maybe the most surprising benefit of optimism is health. If we expect the future to be bright, stress and anxiety are reduced.

    3つの理由により間違っているということが 分かっています

  • So all in all, optimism has lots of benefits.

    第一に 結果がどうであっても 成功しても失敗しても

  • But the question that was really confusing to me was, how do we maintain optimism in the face of reality?

    期待が高い人の方が 常に幸福度は高いのです

  • As an neuroscientist, this was especially confusing, because according to all the theories out there

    何故ならば 恋人に振られたり 会社で賞をもらった時に どのように感じるかは

  • when your expectations are not met, you should alter them.

    その出来事をどう解釈するかによるからです

  • But this is not what we find

    心理学者のマーガレット・マーシャルと ジョン・ブラウンは

  • We asked people to come into our lab in order to try and figure out what was going on.

    期待の高い生徒と 低い生徒を比較してみました

  • We asked them to estimate their likelihood of experiencing different terrible events in their lives

    期待が高い生徒が成功すると

  • So, for example, what is your likelihood of suffering from cancer?

    その原因を自分の才能によるものとします

  • And then we told them the average likelihood of someone like them to suffer these misfortunes.

    「僕は天才だからAを取ったし

  • So cancer, for example, is about 30 percent. And then we asked them again, "How likely are you to suffer from cancer?"

    これからもずっとAを取り続ける」

  • What we wanted to know was whether people will take the information that we gave them to change their beliefs.

    失敗しても それは頭が悪いからではなく

  • And indeed they did -- but mostly when the information we gave them was better than what they expected.

    たまたま試験が不公平だったからであり

  • So for example, if someone said, "My likelihood of suffering from cancer is about 50 percent,"

    次回の成績はもっと良くなると考えます

  • and we said, "Hey, good news. The average likelihood is only 30 percent," the next time around they would say

    期待が低い生徒はその反対です

  • Well maybe my likelihood is about 35 percent." So they learned quickly and efficiently.

    失敗したのは頭が悪いからであり

  • But if someone started off saying, "My average likelihood of suffering from cancer is about 10 percent,"

    成功した場合は

  • and we said, "Hey, bad news. The average likelihood is about 30 percent," the next time around they would say

    試験がたまたま簡単過ぎたからというだけで

  • Yep. Still think it's about 11 percent

    次回は現実が待っている と考えます

  • So it's not that they didn't learn at all -- they did

    どっちにしても比較的不幸に感じています

  • but much, much less than when we gave them positive information about the future

    第二に 結果の良し悪しに関わらず

  • And it's not that they didn't remember the numbers that we gave them;

    何かを心待ちにしているだけで幸せに感じるからです

  • everyone remembers that the average likelihood of cancer is about 30 percent and the average likelihood of divorce is about 40 percent

    行動経済学者のジョージ・ローウェンスタインは

  • But they didn't think that those numbers were related to them.

    彼の大学の生徒に聞きました

  • What this means is that warning signs such as these may only have limited impact

    好きな有名人の誰かと情熱的なキスができるとたら

  • Yes, smoking kills, but mostly it kills the other guy.

    その有名人とのキスのために

  • What I wanted to know was what was going on inside the human brain that prevented us from taking these warning signs personally

    どれくらいのお金を払いますか?

  • . But at the same time, when we hear that the housing market is hopeful, we think

    もし今すぐにキスをするとしたら?

  • Oh, my house is definitely going to double in price

    3時間後 24時間後 3日後

  • To try and figure that out, I asked the participants in the experiment to lie in a brain imaging scanner

    1年後 あるいは10年後の場合は?

  • It looks like this. And using a method called functional MRI

    生徒たちが最も多くお金を払うと答えたのは

  • we were able to identify regions in the brain that were responding to positive information.

    すぐにキスする場合ではなく

  • One of these regions is called the left inferior frontal gyrus

    3日後のキスだったのです

  • So if someone said, "My likelihood of suffering from cancer is 50 percent

    待つことに対して より多く対価を払う意思があったのです

  • and we said, "Hey, good news. Average likelihood is 30 percent,"

    まず 1年や10年も待つつもりは無かったみたいですね

  • the left inferior frontal gyrus would respond fiercely

    だって年老いた有名人はいやでしょうから

  • And it didn't matter if you're an extreme optimist, a mild optimist or slightly pessimistic,

    しかし3日間というのは最適な待ち時間のようでした

  • everyone's left inferior frontal gyrus was functioning perfectly well, whether you're Barack Obama or Woody Allen.

    なぜでしょうか?

  • On the other side of the brain, the right inferior frontal gyrus was responding to bad news

    今すぐキスをしてしまったら それで終わりです

  • And here's the thing: it wasn't doing a very good job

    しかし3日後のキスであれば

  • The more optimistic you were, the less likely this region was to respond to unexpected negative information

    3日間 じらされるような期待感と 待たされるスリルが味わえます

  • And if your brain is failing at integrating bad news about the future, you will constantly leave your rose-tinted spectacles on.

    生徒たちは想像する時間がほしかったのです

  • So we wanted to know, could we change this?

    どこでキスされるのだろう

  • Could we alter people's optimism bias by interfering with the brain activity in these regions?

    どんな感じにキスされるんだろう と

  • And there's a way for us to do that.

    期待感で幸せになるのです

  • This is my collaborator Ryota Kanai.

    皆さんが 日曜日よりも金曜日の方が 好きなのも同じ理由です

  • And what he's doing is he's passing a small magnetic pulse through the skull of the participant in our study into their inferior frontal gyrus.

    本当に興味深い事実ですよね

  • And by doing that, he's interfering with the activity of this brain region for about half an hour

    だって金曜日は働く日で 日曜日は遊ぶ日なのですから

  • After that everything goes back to normal, I assure you.

    当然 人々は日曜日の方が嬉しいと思いますよね

  • So let's see what happens. First of all, I'm going to show you the average amount of bias that we see.

    でも違います

  • So if I was to test all of you now, this is the amount that you would learn more from good news relative to bad news.

    これは オフィスに居るのが大好きだとか

  • Now we interfere with the region that we found to integrate negative information in this task, and the optimism bias grew even larger.

    公園を散歩するのが大嫌いだとか

  • We made people more biased in the way that they process information.

    まったりしたブランチが大嫌いということではありません

  • Then we interfered with the brain region that we found to integrate good news in this task, and the optimism bias disappeared

    なぜなら みなさんに

  • We were quite amazed by these results because we were able to eliminate a deep-rooted bias in humans.

    1週間の内で本当に好きな曜日を尋ねると

  • And at this point we stopped and we asked ourselves, would we want to shatter the optimism illusion into tiny little bits?

    予測通り 土曜日が一番人気でした

  • If we could do that, would we want to take people's optimism bias away?

    その次に金曜日 それから日曜日です

  • Well I've already told you about all of the benefits of the optimism bias,

    みなさんが金曜日が好きなのは

  • which probably makes you want to hold onto it for dear life. But there are,

    金曜日にはその後に続く週末や

  • of course, pitfalls, and it would be really foolish of us to ignore them.

    計画していることへの期待感があるからです

  • Take for example this email I received from a firefighter here in California.

    日曜日の場合 その後に期待できるのは

  • He says, "Fatality investigations for firefighters often include 'We didn't think the fire was going to do that,'

    仕事をする1週間しかありません

  • even when all of the available information was there to make safe decisions.

    楽観主義者とは より多くのキスを期待し

  • This captain is going to use our findings on the optimism bias to try to explain to the firefighters why they think the way they do

    公園でより多く散歩することを 期待する人々なのです

  • to make them acutely aware of this very optimistic bias in humans.

    そして その期待感が幸福度を増すのです

  • So unrealistic optimism can lead to risky behavior, to financial collapse, to faulty planning.

    実際 楽観主義バイアスが無ければ

  • The British government, for example

    私たち全員 やや鬱状態になるでしょう

  • has acknowledged that the optimism bias can make individuals more likely to underestimate the costs and durations of projects.

    やや鬱状態の人は

  • So they have adjusted the 2012 Olympic budget for the optimism bias.

    将来にバイアスをかけません

  • My friend who's getting married in a few weeks has done the same for his wedding budget.

    彼等は健康的な人間と比べて 現実的なのです

  • And by the way, when I asked him about his own likelihood of divorce,

    しかし強度の鬱状態にある人は

  • he said he was quite sure it was zero percent.

    悲観主義バイアスがあります

  • So what we would really like to do, is we would like to protect ourselves from the dangers of optimism,

    彼等は将来が

  • but at the same time remain hopeful, benefiting from the many fruits of optimism.

    実際よりも悪いと予測します

  • And I believe there's a way for us to do that. The key here really is knowledge.

    楽観主義は主観的な現実を変えるわけです

  • We're not born with an innate understanding of our biases

    将来に対する期待が、世界の見方を変えるのです

  • These have to be identified by scientific investigation

    しかし 客観的な現実さえも変えてしまいます

  • But the good news is that becoming aware of the optimism bias does not shatter the illusion. It's like visual illusions

    自己充足的予言として働くのです

  • in which understanding them does not make them go away

    そして これが期待を低くすることが

  • And this is good because it means we should be able to strike a balance

    幸せに繋がらない三つ目の理由です

  • to come up with plans and rules to protect ourselves from unrealistic optimism, but at the same time remain hopeful.

    制御実験の結果

  • I think this cartoon portrays it nicely

    楽観主義は成功と関係しているだけでなく

  • Because if you're one of these pessimistic penguins up there who just does not believe they can fly

    成功を導くということが分かっています

  • Youll certainly never will. Because to make any kind of progress, we need to be able to imagine a different reality

    楽観主義は学問やスポーツ そして 政治における成功に繋がっています

  • and then we need to believe that that reality is possible.

    そして一番意外な楽観主義の恩恵は 健康です

  • But if you are an extreme optimistic penguin who just jumps down blindly hoping for the best,

    未来が明るいと信じていれば

  • you might find yourself in a bit of a mess when you hit the ground

    ストレスと不安は軽減されます

  • But if you're an optimistic penguin who believes they can fly,

    結論として 楽観主義には多くの利点があります

  • but then adjusts a parachute to your back just in case things don't work out exactly as you had planned,

    しかし私はとても不思議に思ったのですが

  • you will soar like an eagle, even if you're just a penguin.

    現実に直面しながらも どうやって 楽観主義を維持できるのでしょうか?

  • Thank you.

    神経科学者としてはこれは特に不可解でした

I'm going to talk to you about optimism -- or more precisely

翻訳: Shuichi Sakai 校正: Shinji Nakagawa

字幕と単語

B1 中級 日本語 楽観主義 バイアス 確率 期待 キス 被験

【TED】ターリ・シャーロット: 楽観主義バイアス (The optimism bias | Tali Sharot)

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    Go Tutor   に公開 2014 年 12 月 11 日
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