Placeholder Image

字幕表 動画を再生する

  • If there's one city in the world

    翻訳: Yasushi Aoki 校正: Yuko Yoshida

  • where it's hard to find a place to buy or rent,

    家を買ったり 借りたりするのが

  • it's Sydney.


  • And if you've tried to find a home here recently,


  • you're familiar with the problem.

    最近 この街で家探しを したことのある人なら

  • Every time you walk into an open house,

    この問題は お馴染みでしょう

  • you get some information about what's out there

    売り出し中の家に 足を踏み入れれば

  • and what's on the market,


  • but every time you walk out,


  • you're running the risk of the very best place passing you by.


  • So how do you know when to switch from looking

    最高の掘り出し物を 逃してしまうリスクがあります

  • to being ready to make an offer?

    探すのを止めて契約へと 進めるべきタイミングは

  • This is such a cruel and familiar problem


  • that it might come as a surprise that it has a simple solution.

    これはとても無情かつ よくある問題なので

  • 37 percent.

    簡単な答えがあると言ったら 驚くかもしれません

  • (Laughter)


  • If you want to maximize the probability that you find the very best place,


  • you should look at 37 percent of what's on the market,

    最高のものを見付けられる 可能性を最大化したければ

  • and then make an offer on the next place you see,

    出ている物件の 37%を見て

  • which is better than anything that you've seen so far.

    次に出会った これまでで一番良いやつに

  • Or if you're looking for a month, take 37 percent of that time --


  • 11 days, to set a standard --


  • and then you're ready to act.

    37%の時間— 11日間で基準を決め

  • We know this because trying to find a place to live


  • is an example of an optimal stopping problem.


  • A class of problems that has been studied extensively

    家を探すというのは 「最適停止問題」の一例だからで

  • by mathematicians and computer scientists.

    これは数学者や コンピューター科学者によって

  • I'm a computational cognitive scientist.

    よく研究されている 問題なんです

  • I spend my time trying to understand


  • how it is that human minds work,

    驚くほどの偉業もすれば ひどい機能不全にもなる

  • from our amazing successes to our dismal failures.

    人間の心の働きを 理解しようと

  • To do that, I think about the computational structure


  • of the problems that arise in everyday life,


  • and compare the ideal solutions to those problems

    日常で現れる問題の 計算論的な構造を考え

  • to the way that we actually behave.

    その問題への 理想的な解決法と

  • As a side effect,

    私達が実際にしている行動とを 比較します

  • I get to see how applying a little bit of computer science


  • can make human decision-making easier.

    コンピューター科学を 少しばかり適用することで

  • I have a personal motivation for this.

    人間の意思決定は 楽にできることが分かりました

  • Growing up in Perth as an overly cerebral kid ...

    これには個人的な 動機があります

  • (Laughter)

    頭でっかちな子供として パースで育った私は—

  • I would always try and act in the way that I thought was rational,


  • reasoning through every decision,

    常に合理的と思える 方法を求め

  • trying to figure out the very best action to take.


  • But this is an approach that doesn't scale up

    取るべき最善の行動を 見出そうとしていました

  • when you start to run into the sorts of problems


  • that arise in adult life.

    大人の生活に持ち上がってくる 諸々の問題に

  • At one point, I even tried to break up with my girlfriend


  • because trying to take into account her preferences as well as my own

    私はそのために恋人と別れようと 思ったことさえありました

  • and then find perfect solutions --


  • (Laughter)

    完璧な答えを 見出そうとすることに—

  • was just leaving me exhausted.


  • (Laughter)


  • She pointed out that I was taking the wrong approach


  • to solving this problem --

    私はこの問題に 間違ったアプローチをしていると

  • and she later became my wife.


  • (Laughter)

    その子は後に 私の妻になりました

  • (Applause)


  • Whether it's as basic as trying to decide what restaurant to go to


  • or as important as trying to decide who to spend the rest of your life with,

    どのレストランに行くか決めるという 簡単な問題から

  • human lives are filled with computational problems

    残りの人生を共に歩む相手を決めるという 重大な問題まで

  • that are just too hard to solve by applying sheer effort.

    人生は 計算論的な問題に 満ちていて

  • For those problems,

    単に根性で解決しようとするには 難しすぎます

  • it's worth consulting the experts:


  • computer scientists.

    専門家の意見を 聞くのがいいでしょう

  • (Laughter)


  • When you're looking for life advice,


  • computer scientists probably aren't the first people you think to talk to.


  • Living life like a computer --

    コンピューター科学者というのは 最初に思い付く相手ではないでしょう

  • stereotypically deterministic, exhaustive and exact --

    コンピューターみたいに 暮らしていて

  • doesn't sound like a lot of fun.

    ステレオタイプとしては 正確 網羅的で 時計仕掛けのようで

  • But thinking about the computer science of human decisions


  • reveals that in fact, we've got this backwards.

    しかし人間の意思決定を コンピューター科学で考えると

  • When applied to the sorts of difficult problems


  • that arise in human lives,

    人間の生活に 現れるような

  • the way that computers actually solve those problems

    難しい問題に 適用するときには

  • looks a lot more like the way that people really act.

    コンピューターは 人間の行動とよく似た方法で

  • Take the example of trying to decide what restaurant to go to.


  • This is a problem that has a particular computational structure.

    たとえば どのレストランに行くか 決めようとしているとしましょう

  • You've got a set of options,

    これは ある計算論的な 構造を持った問題です

  • you're going to choose one of those options,


  • and you're going to face exactly the same decision tomorrow.


  • In that situation,

    同じ問題に 明日も 直面することになります

  • you run up against what computer scientists call


  • the "explore-exploit trade-off."

    「探索と活用のトレードオフ」と コンピューター科学者が呼ぶものが生じ

  • You have to make a decision

    「探索と活用のトレードオフ」と コンピューター科学者が呼ぶものが生じ

  • about whether you're going to try something new --

    ある決断を しなければなりません

  • exploring, gathering some information


  • that you might be able to use in the future --

    将来使える情報を 集めるために

  • or whether you're going to go to a place that you already know is pretty good --


  • exploiting the information that you've already gathered so far.

    あるいは 結構良いと 既に分かっているところに行き

  • The explore/exploit trade-off shows up any time you have to choose

    これまでに集めた情報を 「活用」するか

  • between trying something new


  • and going with something that you already know is pretty good,


  • whether it's listening to music

    結構良いことが分かっているもので 手を打つかを選ぶ時に生じるもので

  • or trying to decide who you're going to spend time with.


  • It's also the problem that technology companies face

    誰と一緒に過ごすか 決める時でもそうです

  • when they're trying to do something like decide what ad to show on a web page.

    これはまた ウェブサイトに出す 広告を決めるような時に

  • Should they show a new ad and learn something about it,

    テクノロジー企業が 直面する問題でもあります

  • or should they show you an ad

    新しい広告を出して そこから学ぶべきか

  • that they already know there's a good chance you're going to click on?

    それとも 多くの人がクリックするのが 分かっている広告を出すべきか

  • Over the last 60 years,

    それとも 多くの人がクリックするのが 分かっている広告を出すべきか

  • computer scientists have made a lot of progress understanding

    これまでの60年で コンピューター科学者は

  • the explore/exploit trade-off,

    これまでの60年で コンピューター科学者は

  • and their results offer some surprising insights.

    探索と活用のトレードオフについての 理解を深め

  • When you're trying to decide what restaurant to go to,

    驚くような洞察も 得られています

  • the first question you should ask yourself

    どのレストランに行くか 決めようとするとき

  • is how much longer you're going to be in town.


  • If you're just going to be there for a short time,

    その街に あとどれくらい いるのかということです

  • then you should exploit.


  • There's no point gathering information.


  • Just go to a place you already know is good.

    情報を集めても しょうがないので

  • But if you're going to be there for a longer time, explore.

    良いと分かっているところに 行けばいい

  • Try something new, because the information you get

    でも長くいることになるのであれば 探索しましょう

  • is something that can improve your choices in the future.

    新しいことを試し 得られた情報で

  • The value of information increases

    将来より良い選択が できるでしょう

  • the more opportunities you're going to have to use it.


  • This principle can give us insight

    その情報を使う機会が 多いほど大きくなります

  • into the structure of a human life as well.

    この原理は人間の 一生の流れについても

  • Babies don't have a reputation for being particularly rational.


  • They're always trying new things,

    赤ちゃんは分別という点では あまり評判が良くありません

  • and you know, trying to stick them in their mouths.


  • But in fact, this is exactly what they should be doing.


  • They're in the explore phase of their lives,

    でも これはまさに赤ちゃんが すべきことなんです

  • and some of those things could turn out to be delicious.


  • At the other end of the spectrum,

    試したものの中には おいしいものもあるでしょう

  • the old guy who always goes to the same restaurant

    反対に お年寄りだと

  • and always eats the same thing

    いつも同じ レストランに行って

  • isn't boring --

    いつも同じものを 食べる人がいますが

  • he's optimal.

    これは退屈な あり方ではなく

  • (Laughter)


  • He's exploiting the knowledge that he's earned


  • through a lifetime's experience.

    人生の経験を 通して得た知識を

  • More generally,


  • knowing about the explore/exploit trade-off


  • can make it a little easier for you to sort of relax and go easier on yourself

    探索と活用のトレードオフを 理解していると

  • when you're trying to make a decision.


  • You don't have to go to the best restaurant every night.

    自分に寛容になれて 気が楽になります

  • Take a chance, try something new, explore.

    毎晩最高のレストランに 行く必要はありません

  • You might learn something.

    思い切って何か新しいものを試し 探索すればいい

  • And the information that you gain


  • is going to be worth more than one pretty good dinner.


  • Computer science can also help to make it easier on us

    1度のおいしい晩ご飯よりも 価値があるでしょう

  • in other places at home and in the office.


  • If you've ever had to tidy up your wardrobe,

    家庭や仕事場ですることも 楽にしてくれます

  • you've run into a particularly agonizing decision:

    衣類を整理しなければ ならなくて

  • you have to decide what things you're going to keep

    難しい決断を迫られたことが あるかもしれません

  • and what things you're going to give away.

    どれを取っておき どれを手放すか

  • Martha Stewart turns out to have thought very hard about this --


  • (Laughter)

    マーサ・スチュワートはこの問題について 一生懸命考えたようです

  • and she has some good advice.


  • She says, "Ask yourself four questions:


  • How long have I had it?

    彼女曰く 「4つのことを自問しましょう

  • Does it still function?

    どれほど長く 所持しているか?

  • Is it a duplicate of something that I already own?


  • And when was the last time I wore it or used it?"

    持っている他のものと かぶっていないか?

  • But there's another group of experts

    それを最後に 使ったのはいつか?」

  • who perhaps thought even harder about this problem,


  • and they would say one of these questions is more important than the others.

    さらに熱心に考察している 専門家がいて

  • Those experts?

    この質問の中の1つは 他の3つよりも重要だと指摘するでしょう

  • The people who design the memory systems of computers.


  • Most computers have two kinds of memory systems:

    コンピューターの記憶システムの 設計者です

  • a fast memory system,

    コンピューターの多くは 2種類の記憶システムを持っています

  • like a set of memory chips that has limited capacity,


  • because those chips are expensive,


  • and a slow memory system, which is much larger.

    高価で容量が 限られているものと

  • In order for the computer to operate as efficiently as possible,

    ずっと大容量で低速な 記憶システムです

  • you want to make sure

    コンピューターをできるだけ 効率的に作動させるためには

  • that the pieces of information you want to access

    使うデータは 素早く取り出せるよう

  • are in the fast memory system,

    使うデータは 素早く取り出せるよう

  • so that you can get to them quickly.

    高速な記憶システムに 入っているようにすべきです

  • Each time you access a piece of information,

    高速な記憶システムに 入っているようにすべきです

  • it's loaded into the fast memory


  • and the computer has to decide which item it has to remove from that memory,

    高速な記憶システムに 取り込まれますが

  • because it has limited capacity.


  • Over the years,

    代わりにどのデータを取り除くか 決めなければなりません

  • computer scientists have tried a few different strategies

    コンピューター科学者たちは 長年にわたり

  • for deciding what to remove from the fast memory.

    高速記憶から取り除くデータを 決める方法を

  • They've tried things like choosing something at random


  • or applying what's called the "first-in, first-out principle,"


  • which means removing the item


  • which has been in the memory for the longest.

    一番長くメモリーに 入っているものを

  • But the strategy that's most effective


  • focuses on the items which have been least recently used.


  • This says if you're going to decide to remove something from memory,

    最も長く使われていないものを 選ぶという方法です

  • you should take out the thing which was last accessed the furthest in the past.

    メモリーから何か 取り除こうというときには

  • And there's a certain kind of logic to this.

    最後に使われた時点が 最も古いものを選ぶということです

  • If it's been a long time since you last accessed that piece of information,


  • it's probably going to be a long time

    そのデータを最後に使ってから 長い時間が過ぎているのなら

  • before you're going to need to access it again.


  • Your wardrobe is just like the computer's memory.


  • You have limited capacity,

    衣装ダンスもコンピューターの メモリーと似たようなものです

  • and you need to try and get in there the things that you're most likely to need


  • so that you can get to them as quickly as possible.


  • Recognizing that,

    最も必要になりそうなものを そこに入れておきたい

  • maybe it's worth applying the least recently used principle

    そうであれば 衣装ダンスの整理にも

  • to organizing your wardrobe as well.

    そうであれば 衣装ダンスの整理にも

  • So if we go back to Martha's four questions,

    この「最長未使用原則」を 適用すると良いかもしれません

  • the computer scientists would say that of these,


  • the last one is the most important.

    コンピューター科学者は この中で

  • This idea of organizing things

    最後の質問が 一番重要だと言うでしょう

  • so that the things you are most likely to need are most accessible


  • can also be applied in your office.

    最も取り出しやすいところに来るよう 整理するというアイデアは

  • The Japanese economist Yukio Noguchi


  • actually invented a filing system that has exactly this property.

    日本の経済学者の 野口悠紀雄は

  • He started with a cardboard box,

    まさにこの性質を持つ 書類整理法を考案しました

  • and he put his documents into the box from the left-hand side.


  • Each time he'd add a document,


  • he'd move what was in there along


  • and he'd add that document to the left-hand side of the box.

    元からあるものを 右にずらして

  • And each time he accessed a document, he'd take it out,


  • consult it and put it back in on the left-hand side.

    書類を使うときは 箱から取り出し

  • As a result, the documents would be ordered from left to right

    使った後は 箱の左端に戻します

  • by how recently they had been used.

    そうすることで 書類は左から右に

  • And he found he could quickly find what he was looking for

    最近使われた順で 並ぶことになります

  • by starting at the left-hand side of the box


  • and working his way to the right.

    左から右へと 見ていくことで

  • Before you dash home and implement this filing system --

    素早く見付けられると 彼は気付きました

  • (Laughter)

    家へと急ぎ戻って この書類システムを作ろうとする前に—

  • it's worth recognizing that you probably already have.


  • (Laughter)

    たぶん皆さんはこれを既に お持ちであることを指摘しておきます

  • That pile of papers on your desk ...


  • typically maligned as messy and disorganized,


  • a pile of papers is, in fact, perfectly organized --

    乱雑で整理されていないと 言われがちですが

  • (Laughter)

    書類の山というのは 実は完璧に整理されているのです

  • as long as you, when you take a paper out,


  • put it back on the top of the pile,


  • then those papers are going to be ordered from top to bottom


  • by how recently they were used,

    書類は常に 上から下へ

  • and you can probably quickly find what you're looking for

    最近使われた順に 並んでいます

  • by starting at the top of the pile.


  • Organizing your wardrobe or your desk

    探している書類を速やかに 見付けられるでしょう

  • are probably not the most pressing problems in your life.

    衣装ダンスや机を 整理するというのは

  • Sometimes the problems we have to solve are simply very, very hard.

    皆さんにとって人生で最も 切迫した問題ではないでしょう

  • But even in those cases,

    私達が解決しなければならない問題が 単にすごく難しいということもあります

  • computer science can offer some strategies

    そういう場合でも コンピューター科学は

  • and perhaps some solace.

    そういう場合でも コンピューター科学は

  • The best algorithms are about doing what makes the most sense

    何らかの戦略や慰めを 提供できます

  • in the least amount of time.


  • When computers