Why We Help


By Martin A. Nowak M. A. ノワック
English 日本語 日本語
Last April, as reactors at Japan’s Fukushima daiichi nuclear power plant were melting down following a lethal earthquake and tsunami, a maintenance worker in his 20s was among those who volunteered to reenter the plant to try to help bring things back under control. He knew the air was poisoned and expected the choice would keep him from ever marrying or having children for fear of burdening them with health consequences. Yet still he walked back through Fukushima’s gates into the plant’s radiation-infused air and got to work—for no more compensation than his usual modest wages. “There are only some of us who can do this job,” the worker, who wished to remain anonymous, told The Independent last July. “I’m single and young, and I feel it’s my duty to help settle this problem.”  昨年4月,破壊的な地震と津波を受けて福島第1原子力発電所の原子炉がメルトダウンしつつあったとき,原子炉を復旧するために再び発電所に入ることを志願した人々がいた。その1人,20代の保守作業員は,所内の空気が汚染されていることを知っていたし,この選択によって,子どもへの健康被害を恐れて結婚や子どもを持つことをあきらめざるを得なくなる可能性も覚悟していた。それでも彼はゲートをくぐり,放射能に汚染された空気が充満する発電所に戻って行った。それに対する報酬は,通常どおりのささやかな賃金だけだった。
Although they may not always play out on such an epic scale, examples of selfless behavior abound in nature. Cells within an organism coordinate to keep their division in check and avoid causing cancer, worker ants in many species sacrifice their own fecundity to serve their queen and colony, female lions within a pride will suckle one another’s young. And humans help other humans to do everything from obtaining food to finding mates to defending territory. Even if the helpers may not necessarily be putting their lives on the line, they are risking lowering their own reproductive success for the benefit of another individual.  これほど劇的ではないにしても,無私無欲の行動の例は自然界にあふれている。生物の体の細胞は協調して自身の分裂を抑制し,がんの発生を防いでいる。また,多くの種の働きアリは自分の生殖能力を犠牲にして女王とコロニーに尽くし,同じ群れの雌ライオンは互いの子どもに授乳する。そして人間は,食物を手に入れてやったり,結婚相手を探してやったり,縄張りを守ってやったりと,すべてにおいて他者を助ける。命を差し出すほどではないにしろ,助ける側は他者の利益のために自身の繁殖成功率を下げる危険を冒しているのだ。
For decades biologists have fretted over cooperation, scrambling to make sense of it in light of the dominant view of evolution as “red in tooth and claw,” as Alfred, Lord Tennyson so vividly described it. Charles Darwin, in making his case for evolution by natural selection—wherein individuals with desirable traits reproduce more often than their peers and thus contribute more to the next generation—called this competition the “struggle for life most severe.” Taken to its logical extreme, the argument quickly leads to the conclusion that one should never ever help a rival and that an individual might in fact do well to lie and cheat to get ahead. Winning the game of life—by hook or by crook—is all that matters.  進化を主に「弱肉強食」,テニソン卿(Alfred, Lord Tennyson)の生々しい表現を借りれば「歯とかぎ爪の赤(血)」と考えてきた生物学者は,協力をどう理解すべきか何十年にもわたって頭を悩ませてきた。
 自然選択による進化(好ましい形質を持つ個体は他の個体よりも繁殖できる可能性が高く,次の世代により多くの子孫を残すという考え方)を提唱したダーウィン(Charles Darwin)は,この争いを「最も厳しい生存競争」と呼んだ。この論理を極端まで進めると,ライバルを決して助けてはならず,競争に勝つには嘘をつき不正行為をするのも致し方ないという結論になる。どんな手段を使ってでも,人生というゲームに勝つことこそが最も重要なのだ。
Why, then, is selfless behavior such a pervasive phenomenon? Over the past two decades I have been using the tools of game theory to study this apparent paradox. My work indicates that instead of opposing competition, cooperation has operated alongside it from the get-go to shape the evolution of life on earth, from the first cells to Homo sapiens. Life is therefore not just a struggle for survival—it is also, one might say, a snuggle for survival. And in no case has the evolutionary influence of cooperation been more profoundly felt than in humans. My findings hint at why this should be the case and underscore that just as helping one another was the key to our success in the past, so, too, is it poised to be vital to our future.  ではなぜ,無私無欲の行動が広く見られるのだろうか? 私は過去20年間,「ゲーム理論」の手法を使って,一見するとパラドックスに思えるこの行動を研究してきた。それによると,協力は競争に対立するものではなく,細胞の誕生から人類に至る地球生命の進化に,生命誕生時から競争とともに影響を及ぼしてきたようだ。