猿の経済界にも見られる不合理性

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人間ほど賢い生き物はいないのに 決断力に関しては 驚くほど愚かな決断を してしまう

ヒトに関する２つの事柄を まずお話したいと思います 一つめの事柄は当たり前のように聞こえるかもしれませんが 我々ホモサピエンスは 実に頭の良い種です その頭の良さは 馬鹿げているほどで 他の種がしていないことを こなしています これは周知の事実ですが 虚栄心の強い種でもあるため 自分たちの賢さを示すのが好きなのです シェークスピアから スティーブン・コルベアまで 賢者を見れば 人間とは理性と才能に恵まれ どんな生き物よりも 知的であることがわかります

でも私が強調したいのは 二つめの事柄です 人間ほど賢い生き物はいないのに 決断力に関しては 驚くほど愚かな決断を してしまうことがある点です ニヤニヤしている方 具体的な名前は出しませんので ご心配なく でも過去２年間に 先例のない愚かな出来事がありました 資源採取のために人間がつくった道具が 悲惨な結果を招いたのも 見てきました 我々がつくった金融市場は 確実であったはずなのに 崩壊してしまいました

でも この二つの例は もっとも情けない間違いを 浮き彫りにはしていません 間違いを犯す原因は 少しばかりの困った問題があったり もの笑いのタネになる決断を してしまうからだと解釈したいところですが 社会科学者の研究でわかったのは ほとんどの人は ある状況に置かれると ある種の決まった間違いをするのです 間違いに意外性はなく 人は間違いを繰り返します 警告があっても動じません 否定的な意見を言われると 次に同じ状況に直面するときに 同じ間違いをする傾向があります 人間の本質を研究している私には この点が謎なのです 一番興味があるのは これだけ賢い種である人間が このような間違いを 常にし続けるのか ということです

賢いはずの人間が なぜ解決策を見つけられないのでしょう？ 何が引き金になるのだろうと思いを巡らしていたら 原因になり得る事柄が いくつか浮かびました 一つめは 我々の責任ではないという見解です 人間は賢いので 非常に複雑な環境を つくり出すことができます 時に複雑すぎて自ら作ったものを 理解できないことすらあります 入り組んだ金融市場をつくり 返済しきれない住宅ローンを組んだりします もちろん 対応できない状況に置かれれば ある意味 我々が 物事を悪化させるのもわかります もしそうならば 解決策は至って簡単 扱いきれない技術や 悪影響を及ぼす環境を 見つけたら取り払い より良いものをデザインすれば 人間は期待通りに 立派な種になるはずです

でも混乱状態にあるのは環境ではなく いい加減につくられた人間なのでは？ 社会科学者が人間の間違いを 見つけ出す方法を見ていて 私はそう思いました 人間は同じ間違いを 何度も繰り返す傾向があるため 人間のつくりを 疑ってしまうほどです もし問題が人間自体にあるのなら どう対処すればいいのか わからないことが問題です 間違いをしがちだという事実を受け入れて 問題を避けられるデザインが必要かもしれません

猿の経済的決断の仕方

私が学生と共に究明したかったのは 可能性１と可能性２の違いを見出すことです 必要としていたのは 賢くて 決断力があるけれど 人間を狂わせる材料に 手の届かない生き物 テクノロジーや文化や言葉を 有しない生き物です こうして決定した 研究の協力者はオマキザルです 新世界ザルとも呼ばれるのは 約3500万年前に ヒトから分岐したからです 「ひい」を500万回つけた 我々のひいおばあちゃんと 彼らのひいおばあちゃんが 同一人物であったと 言えるわけです この猿と人間は非常に離れていながらも 親戚にあたります ホリーは人間のような 技術を持ち合わせていません 賢くて可愛い霊長類ですが 人間を狂わせる要素を持ち合わせていないので この実験には完璧です

ホリーを人間と同じ境遇に置いたら 人間と同じ間違いをしたり 間違いから学ぶのか― 実験してみることにしました 数年前 このアイデアを思いつき ホリーは この問題を どう対処するか見てみようということになりました 人間の間違いだけでも あまりにも題材が多くて どこから着手したらいいのか 迷いました この研究を始めたとき 金融崩壊が起き 差し押さえが相次いだので 私たちは金融の領域が 研究題材にいいのではと思ったのです 猿の経済的決断の仕方を観察して 人間同様 愚かな間違いをするか見てみるのです

このとき二つめの問題にぶちあたりました 少々 方法論的な 問題なのですが 猿はお金を使いません スーパーや銀行で 列に並ぶ猿などいないので お金に対する質問を どうやって猿にしたらいいのか 問題になりましたが ともかく 猿に お金の使い方を 教えてみることにしました これはお金の代わりに使った 造り物の通貨です 研究を始めた当初は 単にトークンと呼んでいたもので エール大学で この通貨を使って 人間から食べ物を得るために 猿を調教しました トークンは大したことない

ただの金属片です 海外旅行から持ち帰り 無用になったお金と一緒で 最初 猿はその利用価値が わからなかったので 柵に入れられたトークンを 拾って眺めたものの 特に意味はなしませんでした でも 猿はすぐに トークンを渡せば 食べ物がもらえることに気づきました 猿のメーデーが実践しています 左の二つの写真は 好奇心を 示しているところです 手を差し出す実験者がいて メーデーはこの人が欲しがっていることを察します 渡すと食べ物がもらえます どの猿も 人間にトークンを差し出し 食べ物が得られます ビデオを用意しました メーデーがトークンを差し出し 嬉しそうに待ち 食べ物をもらいます ボス的存在のフィリックスも 辛抱強く待って食べ物をもらいます

あまり訓練をしなくても どの猿も やり方を 覚えてしまいました これは人間が扱うお金と同じなのか それとも 猿が 賢く見えるだけで 実はそうではないのか 疑問に思いました 猿がお金に匹敵するものを本当に使っていたら 猿は自発的に何をするのか 気になりました 人間が金銭の授受をするように 猿も賢いことをすると 想像する人がいるかもしれません トークンがあれば どれだけのものを 買えるのかと 猿が関心をもつのかどうか 突き止めるため

猿の市場をつくり出しました 対象となった猿は 動物園のような社会的囲いの中で通常暮らしています おやつを欲しがるときに 市場へつながる小さな囲いに 誘い込みます そこは人間の市場より 楽しさがある場所にしました 猿がドアをくぐると トークンがたくさん入った 財布が渡されます トークンを使って 物を得られる仕組みです ２人のセールスマンが 商品を用意しています 学生にセールスマンになってもらい それぞれ違う格好をしました 何度も同じことを繰り返し 猿に仕組みを教えました 商品や値段や誰が信頼できるかなどです 実験者が持っている 黄色い小皿に乗っている量が トークン１枚で買えるものです どれもトークン１枚分ですが 時々ぶどうが多く得られるように 設定しました

実際のビデオをご覧ください 猿の視点から撮影したものです これは猿のハニー 市場の開店を待っています 一人は１粒 もう一人は２粒差し出しています 見極め上手なハニーは ぶどう２粒をくれる人を選びました ハニーから学べることはありそうです ハニーに限らず 大半の猿は より多くてより美味しいものを 持っている人を選びました 猿は商品に注目をして トークンに関心をよせました 驚いたのは 経済学者と共に 経済的指針で猿のデータを見てみると 人間がしていることと同じことが 質的にも量的にも 一致したことです 数値を見ただけでは 猿なのか人間なのか区別がつかないほどです

少なくとも 猿と私たちには 本物のお金のように使えるものを 導入できたと感じました 問題は 猿も人間同様に間違いをするのかということです その可能性はいくつかありました 猿の経済界で見かけなかったのは 人間のように 貯金をしないことです コインを使い果たし 帰って行きました また同時に見かけたのは 恥ずかしいことに 盗みを働くのです 機会さえあれば人間からトークンを だまし取ろうとしました 教えたつもりはないのに 盗みを身につけていました

人間同様に 猿も愚かなことをするのか

そこで 人間同様に 猿も愚かなことをするのか 確かめることにしたのです 猿の経済界を放っておけば 数年後には人間に 経済援助を求めてくるかもしれませんが そんなに待っていられないので 時間を短縮するために 経済的な難局に 直面したとき 人間が間違いやすい問題を 猿にも 与えてみることにしました 人がいかに間違いを犯すのかを確かめるには 自分でやってみるのが一番ですから 直感を見るために 実験をしてみましょう

皆さんに 1000ドルずつ 渡したとします そのお金は もう皆さんのものですから 募金でも何でも 好きなように使えます もうちょっと儲かる選択肢があったとします 一つめの選択肢はリスクを伴います 私がコインを投げて表が出たら もう1000ドルプラス 裏が出たら何もなし 増える確率はありますが 高リスクです もう一つの選択肢は 安全志向 金額は500ドルですが 確実にもらえるとしたら どちらを選びますか 大半の人は安全な方を選びます 1500ドルが確実に手に入るなら 賭ける必要はないと言うのです 慎重な選択と言えますね 人はリスクを負うのが嫌なため 合理的だと思うかもしれませんが

同じ問題の 状況を変えた場合 どうなるか見てみましょう 皆さんに2000ドルを 渡したと想像してください 先ほどの２倍も 好きなものが買えます ここで選択です 先ほどとは違って どのようにお金を失うかを考えてもらいます 選択肢は同じ リスクを伴う選択肢は 表が出たら1000ドル失いますが 裏が出たら何も失わずに済みます リスクをかけたくなければ 私に500ドルを渡すだけ

眉にしわを寄せる人が見えますね きっと皆さんも この実験の対象者と同様に この選択肢を与えられると 安全な方は選ばないのかもしれません 人はリスクをかける傾向にあるのです これが合理的でないのは どちらの状況も 選択肢が同じだったからです 1000ドルか2000ドルのどちらかになる選択肢と 1500ドルと決まった選択肢 でも 伴うリスクに関わる直感は 立たされた状況によって異なります

どういうことでしょうか これは心理的な面から生まれる 少なくとも二つの先入観が関係しています まず 絶対数で考える難しさです 1000ドルか2000ドルの選択肢と 1500ドルの選択肢を 天秤にかけなくてはいけません でも選択肢が変わり 相対的に考えるのは簡単です もっともらえる とか 失う額は少ない という具合です これはいいのですが 捉え方を変えることで 選択肢の妥当性の 見極めに影響します これは二つめの傾向につながり 経済学者は損失回避と呼んでいます

赤字になることを嫌うという意味です 人は損失を嫌うため 損失を避けようと することがあります 最後のシナリオで見たのは 対象者はリスクをかけます 何も失いたくないからです これは我々が 損失の覚悟があるとき 非常に厄介になり得るのですが リスクを負うことが多くなります 始末の悪い様々な状況を作り出すものです 株投資家が株を売らないがために損失を出すのは 相対的に考えているからです 住宅市場の人たちが不動産を売り渋ったのは 損を承知で売りたくなかったからです

猿も同じ傾向を示すのか 私たちは興味がありました 猿の市場でも同じ状況をつくりだしたら 人間と同じことをするでしょうか そこで私たちは猿に選択肢を与え 常に同じことをする安全な人と 50％の確率で違う事をする リスク型の人を用意しました そして初めのシナリオのように ボーナスがもらえるようにしました 儲かるチャンスでもあり 失う可能性も出てきます 実際よりも儲けたと思うのです

このような感じです 新しい販売員を紹介します どちらも持っているのは ぶどう１粒 見た目はいいですが ボーナスが出てきます 左の人はおまけをくれるので 合計２粒のぶどうがもらえます 右の人はリスク型で 何もくれない時がありますが 時々２粒もらえるため 合計３粒のときがあります これは皆さんが直面したものと同じ 猿はリスクを回避して 毎回おまけをくれる人を選ぶのか それとも 何ももらえない時を覚悟して 大きなボーナスを得ようとするでしょうか 人間は安全な方を選びました 結果は猿も同じでした 質的にも量的にも 猿は人間と同じ― 判断を下しました

猿の損失との向き合い方を 明らかにするために 別の実験を行いました ここでは 何もくれない ２人の人に会います ぶどうの数が多いので たくさんもらえる印象を与えます ３粒のぶどうに猿は大喜び でも３粒はもらえないことがわかります 左の人は安全型で 毎度 ぶどう１粒を取り上げて 猿には２粒だけ渡します 右の人はリスク型で ３粒くれることもあるため 猿は喜びますが 時々大きな損をする羽目になり １粒しかくれません

猿はどうしたでしょうか 安全型は 毎度２粒もらえます リスク型は３粒の時と１粒の時が混在します 私たちが驚いたのは 猿にこの選択をさせたとき 人間と同様に非合理的な選択をすることです 実験を どう始めるかによって 猿はリスク型を選ぶのです 猿も物事を相対的に 見ていることを示唆しており 損失と儲けは同じ方法では扱っていません

愚かな策略を克服するのは大変

これはどういうことでしょうか 第一に 猿に対して 金融価値のあるお金を与えると 人間と似たことをします 賢い行動もしますが 盗みなどの 好ましくないことをしたり 非合理的なこともするのです 猿は人間と同様に 体系的な失敗をします これがまず第一に示したい点です 猿の金融アドバイザーを雇おうと 考えた方がいると思いますが 猿はかわいいけれど 人間の金融アドバイザー同様に 愚かですから お勧めしません ごめんなさい 言い方が悪かったわ

皆さんが笑うのも 人間の弱点を知っているからですよね 初めの質問で答えたからわかりますね このような間違いは どこから始まるのでしょうか 私たちの願いは 金融制度や技術に ひねりを入れて向上させることでした でもわかったのは このような傾向はもっと深い部分から発生していることです 人間が進化してきた中に 理由が見つけられる可能性もあります 愚かな面が見られるのは 人間だけなのではなく 大昔から猿にも見られたのかもしれません 猿の実験結果を信用するとしたら この愚かな策略は 3500万年も続いているのかもしれません この古くからある策略は ずっと変わらないままなのです

他にはどのようなものがあるでしょうか 愚かな策略を克服するのは大変なのです 人間は進化するうちに 甘いものや脂肪分の多いものを好むようになりました 美味しさを知っているので デザートを見たときに まずそうとは思わず 体にはプラスだと 思うようになっています 経済的な決断に関しても 同じことが起こるというのが 私の推測です 株が下落したり 不動産価値が下がるとき 進化的な意味で 解釈してしまいます 投資家を失敗に招いたり 差し押さえをつくり出す先入観を 乗り越えるのは 非常に難しいことを指しています

人間は 本来の姿でいることを拒む唯一の種だ

これが悲しい現実ですが 喜ばしいことも必要ですね 肯定的側面は 冒頭で触れたように 人間は賢いだけではなく 生物界の中でも 感動するほどに 賢いことです 羽をバタバタさせなくても ここまで飛行機で来れましたし 今しているように コンタクトを使用すれば 近視でも皆さんがちゃんと見えます このように人間は 生まれもった力の限界を 技術などを使って容易に乗り越えています でも限界があることを認識しなければいけません

厄介なことです 作家のカミュは言いました “人間は 本来の姿でいることを拒む唯一の種だ” 限界を知らない限り 限界を乗り越えることは 無理かもしれないのが皮肉ですが 克服できない限界として考えるのではなく 限界を認識して 受け入れて デザイン界に答えを 見つけ出せる希望を抱けます これこそ人間の可能性を最大限にして 立派な種と名乗るための 唯一の方法かもしれません

ありがとう

（拍手）

予想どおりに不合理　　行動経済学が明かす「あなたがそれを選ぶわけ」

原文

I want to start my talk today with two observations about the human species. The first observation is something that you might think is quite obvious, and that's that our species, Homo sapiens, is actually really, really smart -- like, ridiculously smart -- like you're all doing things that no other species on the planet does right now. And this is, of course, not the first time you've probably recognized this. Of course, in addition to being smart, we're also an extremely vain species. So we like pointing out the fact that we're smart. You know, so I could turn to pretty much any sage from Shakespeare to Stephen Colbert to point out things like the fact that we're noble in reason and infinite in faculties and just kind of awesome-er than anything else on the planet when it comes to all things cerebral.

But of course, there's a second observation about the human species that I want to focus on a little bit more, and that's the fact that even though we're actually really smart, sometimes uniquely smart, we can also be incredibly, incredibly dumb when it comes to some aspects of our decision making. Now I'm seeing lots of smirks out there. Don't worry, I'm not going to call anyone in particular out on any aspects of your own mistakes. But of course, just in the last two years we see these unprecedented examples of human ineptitude. And we've watched as the tools we uniquely make to pull the resources out of our environment kind of just blow up in our face. We've watched the financial markets that we uniquely create -- these markets that were supposed to be foolproof -- we've watched them kind of collapse before our eyes.

But both of these two embarrassing examples, I think, don't highlight what I think is most embarrassing about the mistakes that humans make, which is that we'd like to think that the mistakes we make are really just the result of a couple bad apples or a couple really sort of FAIL Blog-worthy decisions. But it turns out, what social scientists are actually learning is that most of us, when put in certain contexts, will actually make very specific mistakes. The errors we make are actually predictable. We make them again and again. And they're actually immune to lots of evidence. When we get negative feedback, we still, the next time we're face with a certain context, tend to make the same errors. And so this has been a real puzzle to me as a sort of scholar of human nature. What I'm most curious about is, how is a species that's as smart as we are capable of such bad and such consistent errors all the time?

You know, we're the smartest thing out there, why can't we figure this out? In some sense, where do our mistakes really come from? And having thought about this a little bit, I see a couple different possibilities. One possibility is, in some sense, it's not really our fault. Because we're a smart species, we can actually create all kinds of environments that are super, super complicated, sometimes too complicated for us to even actually understand, even though we've actually created them. We create financial markets that are super complex. We create mortgage terms that we can't actually deal with. And of course, if we are put in environments where we can't deal with it, in some sense makes sense that we actually might mess certain things up. If this was the case, we'd have a really easy solution to the problem of human error. We'd actually just say, okay, let's figure out the kinds of technologies we can't deal with, the kinds of environments that are bad -- get rid of those, design things better, and we should be the noble species that we expect ourselves to be.

But there's another possibility that I find a little bit more worrying, which is, maybe it's not our environments that are messed up. Maybe it's actually us that's designed badly. This is a hint that I've gotten from watching the ways that social scientists have learned about human errors. And what we see is that people tend to keep making errors exactly the same way, over and over again. It feels like we might almost just be built to make errors in certain ways. This is a possibility that I worry a little bit more about, because, if it's us that's messed up, it's not actually clear how we go about dealing with it. We might just have to accept the fact that we're error prone and try to design things around it.

So this is the question my students and I wanted to get at. How can we tell the difference between possibility one and possibility two? What we need is a population that's basically smart, can make lots of decisions, but doesn't have access to any of the systems we have, any of the things that might mess us up -- no human technology, human culture, maybe even not human language. And so this is why we turned to these guys here. These are one of the guys I work with. This is a brown capuchin monkey. These guys are New World primates, which means they broke off from the human branch about 35 million years ago. This means that your great, great, great great, great, great -- with about five million "greats" in there -- grandmother was probably the same great, great, great, great grandmother with five million "greats" in there as Holly up here. You know, so you can take comfort in the fact that this guy up here is a really really distant, but albeit evolutionary, relative. The good news about Holly though is that she doesn't actually have the same kinds of technologies we do. You know, she's a smart, very cut creature, a primate as well, but she lacks all the stuff we think might be messing us up. So she's the perfect test case.

What if we put Holly into the same context as humans? Does she make the same mistakes as us? Does she not learn from them? And so on. And so this is the kind of thing we decided to do. My students and I got very excited about this a few years ago. We said, all right, let's, you know, throw so problems at Holly, see if she messes these things up. First problem is just, well, where should we start? Because, you know, it's great for us, but bad for humans. We make a lot of mistakes in a lot of different contexts. You know, where are we actually going to start with this? And because we started this work around the time of the financial collapse, around the time when foreclosures were hitting the news, we said, hhmm, maybe we should actually start in the financial domain. Maybe we should look at monkey's economic decisions and try to see if they do the same kinds of dumb things that we do.

Of course, that's when we hit a sort second problem -- a little bit more methodological -- which is that, maybe you guys don't know, but monkeys don't actually use money. I know, you haven't met them. But this is why, you know, they're not in the queue behind you at the grocery store or the ATM -- you know, they don't do this stuff. So now we faced, you know, a little bit of a problem here. How are we actually going to ask monkeys about money if they don't actually use it? So we said, well, maybe we should just, actually just suck it up and teach monkeys how to use money. So that's just what we did. What you're looking at over here is actually the first unit that I know of of non-human currency. We weren't very creative at the time we started these studies, so we just called it a token. But this is the unit of currency that we've taught our monkeys at Yale to actually use with humans, to actually buy different pieces of food. It doesn't look like much -- in fact, it isn't like much.

Like most of our money, it's just a piece of metal. As those of you who've taken currencies home from your trip know, once you get home, it's actually pretty useless. It was useless to the monkeys at first before they realized what they could do with it. When we first gave it to them in their enclosures, they actually kind of picked them up, looked at them. They were these kind of weird things. But very quickly, the monkeys realized that they could actually hand these tokens over to different humans in the lab for some food. And so you see one of our monkeys, Mayday, up here doing this. This is A and B are kind of the points where she's sort of a little bit curious about these things -- doesn't know. There's this waiting hand from a human experimenter, and Mayday quickly figures out, apparently the human wants this. Hands it over, and then gets some food. It turns out not just Mayday, all of our monkeys get good at trading tokens with human salesman. So here's just a quick video of what this looks like. Here's Mayday. She's going to be trading a token for some food and waiting happily and getting her food. Here's Felix, I think. He's our alpha male; he's a kind of big guy. But he too waits patiently, gets his food and goes on.

So the monkeys get really good at this. They're surprisingly good at this with very little training. We just allowed them to pick this up on their own. The question is: is this anything like human money? Is this a market at all, or did we just do a weird psychologist's trick by getting monkeys to do something, looking smart, but not really being smart. And so we said, well, what would the monkeys spontaneously do if this was really their currency, if they were really using it like money? Well, you might actually imagine them to do all the kinds of smart things that humans do when they start exchanging money with each other. You might have them start paying attention to price, paying attention to how much they buy -- sort of keeping track of their monkey token, as it were. Do the monkeys do anything like this?

And so our monkey marketplace was born. The way this works is that our monkeys normally live in a kind of big zoo social enclosure. When they get a hankering for some treats, we actually allowed them a way out into a little smaller enclosure where they could enter the market. Upon entering the market -- it was actually a much more fun market for the monkeys than most human markets because, as the monkeys entered the door of the market, a human would give them a big wallet full of tokens so they could actually trade the tokens with one of these two guys here -- two different possible human salesmen that they could actually buy stuff from. The salesmen were students from my lab. They dressed differently; they were different people. And over time, they did basically the same thing so the monkeys could learn, you know, who sold what at what price -- you know, who was reliable, who wasn't, and so on. And you can see that each of the experimenters is actually holding up a little, yellow food dish. and that's what the monkey can for a single token. So everything costs one token, but as you can see, sometimes tokens buy more than others, sometimes more grapes than others.

So I'll show you a quick video of what this marketplace actually looks like. Here's a monkey-eye-view. Monkeys are shorter, so it's a little short. But here's Honey. She's waiting for the market to open a little impatiently. All of a sudden the market opens. Here's her choice: one grapes or two grapes. You can see Honey, very good market economist, goes with the guy who gives more. She could teach our financial advisers a few things or two. So not just Honey, most of the monkeys went with guys who had more. Most of the monkeys went with guys who had better food. When we introduced sales, we saw the monkeys paid attention to that. They really cared about their monkey token dollar. The more surprising thing was that when we collaborated with economists to actually look at the monkeys' data using economic tools, they basically matched, not just qualitatively, but quantitatively with what we saw humans doing in a real market. So much so that, if you saw the monkeys' numbers, you couldn't tell whether they came from a monkey or a human in the same market.

And what we'd really thought we'd done is like we'd actually introduced something that, at least for the monkeys and us, works like a real financial currency. Question is: do the monkeys start messing up in the same ways we do? Well, we already saw anecdotally a couple of signs that they might. One thing we never saw in the monkey marketplace was any evidence of saving -- you know, just like our own species. The monkeys entered the market, spent their entire budget and then went back to everyone else. The other thing we also spontaneously saw, embarrassingly enough, is spontaneous evidence of larceny. The monkeys would rip-off the tokens at every available opportunity -- from each other, often from us -- you know, things we didn't necessarily think we were introducing, but things we spontaneously saw.

So we said, this looks bad. Can we actually see if the monkeys are doing exactly the same dumb things as humans do? One possibility is just kind of let the monkey financial system play out, you know, see if they start calling us for bailouts in a few years. We were a little impatient so we wanted to sort of speed things up a bit. So we said, let's actually give the monkeys the same kinds of problems that humans tend to get wrong in certain kinds of economic challenges, or certain kinds of economic experiments. And so, since the best way to see how people go wrong is to actually do it yourself, I'm going to give you guys a quick experiment to sort of watch your own financial intuitions in action.

So imagine that right now I handed each and every one of you a thousand U.S. dollars -- so 10 crisp hundred dollar bills. Take these, put it in your wallet and spend a second thinking about what you're going to do with it. Because it's yours now; you can buy whatever you want. Donate it, take it, and so on. Sounds great, but you get one more choice to earn a little bit more money. And here's your choice: you can either be risky, in which case I'm going to flip one of these monkey tokens. If it comes up heads, you're going to get a thousand dollars more. If it comes up tails, you get nothing. So it's a chance to get more, but it's pretty risky. Your other option is a bit safe. Your just going to get some money for sure. I'm just going to give you 500 bucks. You can stick it in your wallet and use it immediately. So see what your intuition is here. Most people actually go with the play-it-safe option. Most people say, why should I be risky when I can get 1,500 dollars for sure? This seems like a good bet. I'm going to go with that. You might say, eh, that's not really irrational. People are a little risk-averse. So what?

Well, the "so what?" comes when start thinking about the same problem set up just a little bit differently. So now imagine that I give each and every one of you 2,000 dollars -- 20 crisp hundred dollar bills. Now you can buy double to stuff you were going to get before. Think about how you'd feel sticking it in your wallet. And now imagine that I have you make another choice But this time, it's a little bit worse. Now, you're going to be deciding how you're going to lose money, but you're going to get the same choice. You can either take a risky loss -- so I'll flip a coin. If it comes up heads, you're going to actually lose a lot. If it comes up tails, you lose nothing, you're fine, get to keep the whole thing -- or you could play it safe, which means you have to reach back into your wallet and give me five of those $100 bills, for certain.

And I'm seeing a lot of furrowed brows out there. So maybe you're having the same intuitions as the subjects that were actually tested in this, which is when presented with these options, people don't choose to play it safe. They actually tend to go a little risky. The reason this is irrational is that we've given people in both situations the same choice. It's a 50/50 shot of a thousand or 2,000, or just 1,500 dollars with certainty. But people's intuitions about how much risk to take varies depending on where they started with.

So what's going on? Well, it turns out that this seems to be the result of at least two biases that we have at the psychological level. One is that we have a really hard time thinking in absolute terms. You really have to do work to figure out, well, one option's a thousand, 2,000; one is 1,500. Instead, we find it very easy to think in very relative terms as options change from one time to another. So we think of things as, "Oh, I'm going to get more," or "Oh, I'm going to get less." This is all well and good, except that changes in different directions actually effect whether or not we think options are good or not. And this leads to the second bias, which economists have called loss aversion.

The idea is that we really hate it when things go into the red. We really hate it when we have to lose out on some money. And this means that sometimes we'll actually switch our preferences to avoid this. What you saw in that last scenario is that subjects get risky because they want the small shot that there won't be any loss. That means when we're in a risk mindset -- excuse me, when we're in a loss mindset, we actually become more risky, which can actually be really worrying. These kinds of things play out in lots of bad ways in humans. They're why stock investors hold onto losing stocks longer -- because they're evaluating them in relative terms. They're why people in the housing market refused to sell their house -- because they don't want to sell at a loss.

The question we were interested in is whether the monkeys show the same biases. If we set up those same scenarios in our little monkey market, would they do the same thing as people? And so this is what we did, we gave the monkeys choices between guys who were safe -- they did the same thing every time -- or guys who were risky -- they did things differently half the time. And then we gave them options that were bonuses -- like you guys did in the first scenario -- so they actually have a chance more, or pieces where they were experiencing losses -- they actually thought they were going to get more than they really got.

And so this is what this looks like. We introduced the monkeys to two new monkey salesmen. The guy on the left and right both start with one piece of grape, so it looks pretty good. But they're going to give the monkeys bonuses. The guy on the left is a safe bonus. All the time, he adds one, to give the monkeys two. The guy on the right is actually a risky bonus. Sometimes the monkeys get no bonus -- so this is a bonus of zero. Sometimes the monkeys get two extra. For a big bonus, now they get three. But this is the same choice you guys just faced. Do the monkeys actually want to play it safe and then go with the guy who's going to do the same thing on every trial, or do they want to be risky and try to get a risky, but big, bonus, but risk the possibility of getting no bonus. People here played it safe. Turns out, the monkeys play it safe too. Qualitatively and quantitatively, they choose exactly the same way as people, when tested in the same thing.

You might say, well, maybe the monkeys just don't like risk. Maybe we should see how they do with losses. And so we ran a second version of this. Now, the monkeys meet two guys who aren't giving them bonuses; they're actually giving them less than they expect. So they look like they're starting out with a big amount. These are three grapes; the monkey's really psyched for this. But now they learn these guys are going to give them less than they expect. They guy on the left is a safe loss. Every single time, he's going to take one of these away and give the monkeys just two. the guy on the right is the risky loss. Sometimes he gives no loss, so the monkeys are really psyched, but sometimes he actually gives a big loss, taking away two to give the monkeys only one.

And so what do the monkeys do? Again, same choice; they can play it safe for always getting two grapes every single time, or they can take a risky bet and choose between one and three. The remarkable thing to us is that, when you give monkeys this choice, they do the same irrational thing that people do. They actually become more risky depending on how the experimenters started. This is crazy because it suggests that the monkeys too are evaluating things in relative terms and actually treating losses differently than they treat gains.

So what does all of this mean? Well, what we've shown is that, first of all, we can actually give the monkeys a financial currency, and they do very similar things with it. They do some of the smart things we do, some of the kind of not so nice things we do, like steal it and so on. But they also do some of the irrational things we do. They systematically get things wrong and in the same ways that we do. This is the first take-home message of the Talk, which is that if you saw the beginning of this and you thought, oh, I'm totally going to go home and hire a capuchin monkey financial adviser. They're way cuter than the one at ... you know -- Don't do that; they're probably going to be just as dumb as the human one you already have. So, you know, a little bad -- Sorry, sorry, sorry. A little bad for monkey investors.

But of course, you know, the reason you're laughing is bad for humans too. Because we've answered the question we started out with. We wanted to know where these kinds of errors came from. And we started with the hope that maybe we can sort of tweak our financial institutions, tweak our technologies to make ourselves better. But what we've learn is that these biases might be a deeper part of us than that. In fact, they might be due to the very nature of our evolutionary history. You know, maybe it's not just humans at the right side of this chain that's duncey. Maybe it's sort of duncey all the way back. And this, if we believe the capuchin monkey results, means that these duncey strategies might be 35 million years old. That's a long time for a strategy to potentially get changed around -- really, really old.

What do we know about other old strategies like this? Well, one thing we know is that they tend to be really hard to overcome. You know, think of our evolutionary predilection for eating sweet things, fatty things like cheesecake. You can't just shut that off. You can't just look at the dessert cart as say, "No, no, no. That looks disgusting to me." We're just built differently. We're going to perceive it as a good thing to go after. My guess is that the same thing is going to be true when humans are perceiving different financial decisions. When you're watching your stocks plummet into the red, when you're watching your house price go down, you're not going to be able to see that in anything but old evolutionary terms. This means that the biases that lead investors to do badly, that lead to the foreclosure crisis are going to be really hard to overcome.

So that's the bad news. The question is: is there any good news? I'm supposed to be up here telling you the good news. Well, the good news, I think, is what I started with at the beginning of the Talk, which is that humans are not only smart; we're really inspirationally smart to the rest of the animals in the biological kingdom. We're so good at overcoming our biological limitations -- you know, I flew over here in an airplane. I didn't have to try to flap my wings. I'm wearing contact lenses now so that I can see all of you. I don't have to rely on my own near-sightedness. We actually have all of these cases where we overcome our biological limitations through technology and other means, seemingly pretty easily. But we have to recognize that we have those limitations.

And here's the rub. It was Camus who once said that, "Man is the only species who refuses to be what he really is." But the irony is that it might only be in recognizing our limitations that we can really actually overcome them. The hope is that you all will think about your limitations, not necessarily as unovercomable, but to recognize them, accept them and then use the world of design to actually figure them out. That might be the only way that we will really be able to achieve our own human potential and really be the noble species we hope to all be.

Thank you.

(Applause)