人類比靈長類祖先聰明多少 Who Apes Whom?
ATLANTA — WHEN I learned last week about the discovery of an early human relative deep in a cave in South Africa, I had many questions. Obviously, they had dug up a fellow primate, but of what kind?
亞特蘭大——上週獲悉在南非一個洞穴的深處發現了早期人類的親屬時，我有很多疑問。顯然，他們又挖出了一種靈長目動物，但屬於哪一類呢？
The fabulous find, named Homo naledi, has rightly been celebrated for both the number of fossils and their completeness. It has australopithecine-like hips and an ape-size brain, yet its feet and teeth are typical of the genus Homo.
憑藉化石的數量和它們的完整性，被稱作“納勒迪人”(Homo naledi)的這個驚人發現的確應該慶祝。它的髖部像南方古猿，大腦體積和猿類的相當，但腳和牙齒卻表現出了典型的人屬特點。
The mixed features of these prehistoric remains upset the received human origin story, according to which bipedalism ushered in technology, dietary change and high intelligence. Part of the new species’ physique lags behind this scenario, while another part is ahead. It is aptly called a mosaic species.
這些史前骨骸表現出的複雜特徵，攪亂了公認的人類起源理論。根據該理論，人類變成兩條腿獨立行走後迎來了技術、飲食變化和高智商。但這個新物種的身體部分停留在這一幕發生之前，另一部分卻已經進化到了這一幕發生之後。叫它組合物種挺恰當的。
We like the new better than the old, though, and treat every fossil as if it must fit somewhere on a timeline leading to the crown of creation. Chris Stringer, a prominent British paleoanthropologist who was not involved in the study, told BBC News: “What we are seeing is more and more species of creatures that suggests that nature was experimenting with how to evolve humans, thus giving rise to several different types of humanlike creatures originating in parallel in different parts of Africa.”
但我們往往喜新厭舊，對待每一塊化石都像是它必須要符合人類進化歷程中的某個節點。未參與該研究的英國著名古人類學家克里斯·斯特林格(Chris Stringer)對BBC新聞(BBC News)表示：“我們看到，越來越多的動物物種表明，大自然是在嘗試各種人類進化的方式，因而產生了幾種不同類型的像人一樣的動物，它們同時發源於非洲的不同地區。”
This represents a shockingly teleological view, as if natural selection is seeking certain outcomes, which it is not. It doesn’t do so any more than a river seeks to reach the ocean.
這就有了一種驚人的目的論色彩，彷彿自然選擇是在追求某些結果。但其實不是這樣。它和河流想要注入大海沒什麼不同。
News reports spoke of a “new ancestor,” even a “new human species,” assuming a ladder heading our way, whereas what we are actually facing when we investigate our ancestry is a tangle of branches. There is no good reason to put Homo naledi on the branch that produced us. Nor does this make the discovery any less interesting.
新聞報道談到了“新祖先”，甚至“新人種”，假想出一條向着我們延伸的梯子，但在調查自己的起源時，我們實際面臨的是一堆雜亂的分支。我們沒有充分的理由去把“納勒迪人”放在那個產生了我們的分支上。這絲毫不會減少這項發現的意義。
Every species in our lineage tells us something about ourselves, because the hominoids (humans, apes and everything in between) are genetically extremely tight. We have had far less time to diverge than the members of many other animal families, like the equids (horses, zebras, donkeys) or canids (wolves, dogs, jackals). If it hadn’t been for the human ego, taxonomists would long ago have squeezed all hominoids into a single genus.
人類譜系中的每一個物種，都會讓我們更瞭解自己，因爲人猿總科動物（人類、猿類和介於這兩之間的一切物種）在基因方面是極爲接近的。我們經歷的分歧過程遠短於很多其他動物科的成員，如馬科動物（馬、斑馬、驢）和犬科動物（狼、狗、豺）。如果不是人類的自我意識，分類學家很久以前就把所有人猿總科動物歸爲一個屬了。
The standard story is that our ancestors first left the apes behind to become australopithecines, which grew more sophisticated and brainier to become us. But what if these stages were genetically mixed up? Some scientists have claimed early hybridization between human and ape DNA. Did our ancestors, after having split off, keep returning to the apes in the same way that today’s grizzlies and polar bears still interbreed occasionally?
標準的說法是，我們的祖先先是從猿進化成了南方古猿，後來又變得更加複雜和聰明，最終變成了我們現在的樣子。但如果這些階段在基因上是混在一起的怎麼辦？一些科學家已經聲稱發現了早期的人猿DNA混合。脫離了猿後，我們的祖先是不斷回到猿那裏去，就像灰熊和北極熊至今還偶爾會雜交繁殖那樣？
Instead of looking forward to a glorious future, our lineage may have remained addicted to the hairy embrace of its progenitors. Other scientists, however, keep sex out of it and speak of incomplete lineage separation. Either way, our heritages are closely intertwined.
我們的譜系沒有憧憬美好未來，反而對祖先那毛茸茸的懷抱戀戀不捨。然而，其他一些科學家將性排除在外，轉而說起了譜系劃分的不完整。不管怎樣，我們遺傳下來的東西都是密切交織在一起的。
The problem is that we keep assuming that there is a point at which we became human. This is about as unlikely as there being a precise wavelength at which the color spectrum turns from orange into red. The typical proposition of how this happened is that of a mental breakthrough — a miraculous spark — that made us radically different. But if we have learned anything from more than 50 years of research on chimpanzees and other intelligent animals, it is that the wall between human and animal cognition is like a Swiss cheese.
問題是，我們一直假定自己是從某一時刻起開始成爲人類的。但要找到這個點，就如同在光譜中找到從桔色變成紅色的那個精確的波長，是不太可能的事。關於這種轉變，有一種典型的理論，即是一種智力上的突破——靈光一閃的奇蹟——使我們驟然改變。但以我們對黑猩猩和其他高智商動物進行的50多年的研究，至少有一個收穫是，人的認知和動物的認知之間那堵牆，就像是一塊瑞士奶酪。
Apart from our language capacity, no uniqueness claim has survived unmodified for more than a decade since it was made. You name it — tool use, tool making, culture, food sharing, theory of mind, planning, empathy, inferential reasoning — it has all been observed in wild primates or, better yet, many of these capacities have been demonstrated in carefully controlled experiments.
除了語言能力，沒有哪個聲稱人類獨具某項技能的論斷會在提出十年後依然堅挺。你能想到的所有技能——使用工具、製造工具、形成文化、分享食物、心智理論、計劃、共情、推理——都已經在野生靈長目動物身上觀察到。更進一步，許多還可以在嚴格控制的動物實驗中演示出來。
We know, for example, that apes plan ahead. They carry tools over long distances to places where they use them, sometimes up to five different sticks and twigs to raid a bee nest or probe for underground ants. In the lab, they fabricate tools in anticipation of future use. Animals think without words, as do we most of the time.
比如，我們知道猿類可以提前做計劃。它們會攜帶工具長途跋涉到需要使用這些工具的地方，有時它們會用多達五種棍子和枝條來對付一個蜂巢，或翻找地下的螞蟻。在實驗室裏，它們會製造工具以備將來使用。動物會不經由語言思考，就像我們大多數時候那樣。
Undeterred by Homo naledi’s relatively small brain, however, the research team sought to stress its humanity by pointing at the bodies in the cave. But if taking this tack implies that only humans mourn their dead, the distinction with apes is being drawn far too sharply.
不過，“納勒迪人”的大腦體積較小並未讓研究團隊退縮，他們轉而通過指出屍體放在洞穴內來突出它們人性的一面。但如果用這一點來表示只有人類纔會哀悼死者，那我們就把自己和猿類的差別劃分得太清晰了。
Apes appear to be deeply affected by the loss of others to the point of going totally silent, seeking comfort from bystanders and going into a funk during which they don’t eat for days. They may not inter their dead, but they do seem to understand death’s irreversibility. After having stared for a long time at a lifeless companion — sometimes grooming or trying to revive him or her — apes move on.
猿類表現出會因爲同伴死亡而深受影響，以至於完全陷入沉默，從旁觀者那裏尋求安慰，或陷入數天不吃東西的逃避狀態。它們可能不會埋葬死去的同類，但它們似乎的確知道死了就不能再復生。長久地盯着死去的同伴——有時會給它們整理皮毛或試圖讓它們復活——之後，猿類會離開。
Since they never stay in one place for long, they have no reason to cover or bury a corpse. Were they to live in a cave or settlement, however, they might notice that carrion attracts scavengers, some of which are formidable predators, like hyenas. It would absolutely not exceed the ape’s mental capacity to solve this problem by either covering odorous corpses or moving them out of the way.
因爲不會長久待在同一個地方，所以它們沒有理由掩蓋或埋葬屍體。但如果是生活在一個洞穴裏或在一個定居點，它們可能會注意到，屍體的腐肉會吸引食腐動物，有些還是難以對付的捕食者，比如鬣狗。猿類絕對有足夠的智能來解決這個問題，要麼把腐臭的屍體掩蓋起來，要麼把它們移到偏僻的地方。
The suggestion by some scholars that this requires belief in an afterlife is pure speculation. We simply don’t know if Homo naledi buried corpses with care and concern or unceremoniously dumped them into a faraway cave to get rid of them.
有些學者認爲做出這樣的行爲需要它們具備來生的觀念，這純粹是猜測。我們根本不知道，“納勒迪人”是以關切的心態埋葬屍體，還是粗暴地將它們拋入偏遠洞穴處理掉。
It is an odd coincidence that “naledi” is an anagram of “denial.” We are trying way too hard to deny that we are modified apes. The discovery of these fossils is a major paleontological breakthrough. Why not seize this moment to overcome our anthropocentrism and recognize the fuzziness of the distinctions within our extended family? We are one rich collection of mosaics, not only genetically and anatomically, but also mentally.
納勒迪(naledi)和否定(denial)這兩個詞，字母相同，排序有異，這是一個詭異的巧合。我們花了太大的力氣來否認自己是經過改變的猿類。發現這些化石的確是古生物學上的重大突破。爲何不利用這次機會來超越人類中心說，承認我們所屬的大家庭裏各個成員的界限並沒有那麼分明？我們是一個組成非常豐富的羣體，不僅從基因和解剖學上講如此，在心智上也是如此。
