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人类和狗成为朋友改变了狗眼的构造
2019-07-02 yzy86 8714 0 0  



Two specialized muscles give them a rangeof expression that wolves’ eyes lack.

副标题:两块特化的肌肉赋予了狗眼在一定幅度内做表情的能力,而这是狼眼不具备的

Dogs, more so than almost any otherdomesticated species, are desperate for human eye contact. When raised aroundpeople, they begin fighting for our attention when they’re as young as fourweeks old. It’s hard for most people to resist a petulant flash of puppy-dogeyes—and according to a new study, that pull on the heartstrings might beexactly why dogs can give us those looks at all.

相比其他任何的驯化物种,狗尤其渴望和人类进行眼神交流。如果它们是在人类周围长大,小至四周大就会开始争夺我们的关注。对大部分人来说,小狗目光中一闪而过的任性是很难抗拒的,而根据一项新的研究,牵动你的心弦可能恰恰就是狗狗给我们那种目光的原因。

A paper published today in the Proceedingsof the National Academy of Sciences found that dogs’ faces are structured forcomplex expression in a way that wolves’ aren’t, thanks to a special pair ofmuscles framing their eyes. These muscles are responsible for that “adopt me”look that dogs can pull by raising their inner eyebrows. It’s the firstbiological evidence scientists have found that domesticated dogs might haveevolved a specialized ability used expressly to communicate better with humans.

一篇发表在《美国国家科学院院刊》上的论文发现:狗脸如此的构造是为了作出复杂的表情,而狼脸就不是这种构造,这多亏了一对很特别的能与眼球配适的肌肉。狗能摆出的那种“收养我吧”的神情就是这些肌肉在起作用,把内眉扬起来就行。这是科学家们找到的第一个生物学证据,证明了已经驯化的狗可能已经演化出了一种特别的能力,专门用来和人类更好地沟通。

For the study, a team at the University ofPortsmouth’s Dog Cognition Centre looked at two muscles that work together towiden and open a dog’s eyes, causing them to appear bigger, droopier, andobjectively cuter. The retractor anguli oculi lateralis muscle and the levatoranguli oculi medialis muscle (mercifully known as RAOL and LAOM) form twoshort, straight lines, which connect the ring of muscle around a dog’s eye toeither end of the brow above.

在这项研究中,朴茨茅斯大学狗类认知中心的一个团队研究了这两块能合力扩张以及打开狗眼的肌肉,它们能让狗眼显得更大、更消沉,乃至在客观上显得更可爱。眼角外侧牵缩肌和眼角内侧上提肌(被仁慈地称为RAOL和LAOM)构成了两条很短的直线,把狗眼周围的肌肉环和上方眉骨的两端连接了起来。

These researchers have long been interestedin the ways dogs make eye contact with humans and, in particular, how they movetheir eyebrows. In 2017, Juliane Kaminski, the lead author of the new paper,found that dogs moved their eyebrows more often while a human paid attention tothem, and less often when they were ignored or given food (which, sorry to say,is a more exciting stimulus for them than human love). That suggested themovement is to some degree voluntary. On our side of these longing glances,research has also shown that when dogs work these muscles, humans respond morepositively. And both man and mutt benefit from a jolt of oxytocin when lockedin on each other.

这些研究人员长久以来一直都对狗和人类进行眼神交流感兴趣,特别是,它们的眉毛是如何动起来的。2017年时,这篇新论文的第一作者朱利亚妮·卡明斯基发现,当有人类把注意力集中在狗狗身上时,它们就会更频繁地动眉毛,而当它们被无视或是接受喂食(很抱歉地说,对它们而言,喂食是一种比人类疼爱更能带来兴奋的刺激)时,动眉毛的频次就会更少。这就意味着,这种行为在一定程度上是自发自愿的。研究也已经表明:当狗狗运作这几块肌肉时,人类的回应也会更为正面。而且,完成互相锁定的时候,人和狗都从这种催产素带来的震颤中受益了。

This isn’t simply a fortuitous love story,in which the eyes of two species just so happen to meet across a crowdedplanet. Like all the best partnerships, this one is more likely the result ofyears of evolution and growth. If dogs developed their skill for eyebrowmanipulation because of their connection to humans, one way to tell would be tolook for the same capacity in wolves. Because dogs split off from their wolfrelatives—specifically, gray wolves—as many as 33,000 years ago, studying thetwo animals is a bit like cracking open a four-legged time capsule. Divergencebetween the two species marked the start of dogs’ domestication, a longevolutionary process influenced—and often directly driven—by humans. Today,researchers can identify and study differences between the species to gain anunderstanding of exactly how dogs have changed over time.

这并不单纯是一个偶然的爱的故事,故事中两个物种的眼神就这样穿越了这个拥挤的星球,交会在一起。如同所有最好的伙伴关系一样,这一对的关系更可能是多年演化和发展的结果。如果狗是出于和人类的关系发展出了操控眉毛的技能,那么有一个辨别的方法,就是在狼身上寻找同样的能力。因为狗和它们的亲戚狼,准确说是灰狼,早在3万3千年前就分道扬镳了,研究这两种动物有点像是在破解一个长着四条腿的时间胶囊。这两个物种各自走上了不同的道路标志着狗被驯化的开始,后者是受人类影响(往往是直接驱动)的一段很漫长的演化历程。今天,研究者有能力鉴识和研究这些物种间的差异,这样就能进一步理解狗在时间长河中到底是如何演变的。

In this case, those eyebrow-raising musclesdo appear to be an addition to dogs’ anatomy. In the four gray wolves theresearchers looked at, neither muscle was present. (They did find bundles offibers that could be the precursors to the RAOL and LAOM.) In five of the sixbreeds of dogs the researchers looked at, both muscles were fully formed andstrong; in the Siberian husky, the wolflike, oldest breed of the group, the researcherswere unable to locate a RAOL.

在这个案例中,那些负责扬起眉毛的肌肉,从狗的解剖学上看,似乎确实是多出来的。而在这些研究者所观察的四只灰狼身上,那两块肌肉一块也不存在。(他们确实找到了一些纤维簇,可能是眼角外侧牵缩肌和眼角内侧上提肌的前身。)在研究者所观察的六个狗种中,有五个狗种的两块肌肉发育都很完全,而且很强健;在很像狼的西伯利亚哈士奇身上,也就是观察对象群中最古老的品种,研究者找不到眼角外侧牵缩肌。

Sometimes, the origins of changes likethese aren’t immediately apparent. Certain physical dog traits—including floppyears and short snouts—likely originate from the same set of developmental cellsthat code for tameness, a preferable trait in household pets, for instance. Inthe case of this new research, though, the connection between the physicaltrait and the related behavior is a bit more direct. “Previous work—and much ofit by these same authors—had shown that these muscles were responsible forenhancing positive responses in humans,” Brian Hare, the director of DukeUniversity’s Canine Cognition Center and the editor of the paper, told TheAtlantic via email, “but the current suggests the origin of these facialexpressions is after dogs split from wolves.”
有时候,诸如此类的演变,起源并不是立刻就能显而易见。狗的特定生物性状,可能源于为驯化编定遗传密码的同一组发育细胞,比如说包括松软的耳朵和短短的口鼻,这是家养宠物更讨喜的性状。但在这项新研究中,生物性状和相关行为之间的联系是更为直接的。“在这之前的工作(一大部分也是这几位作者完成的)已经发现,这些肌肉负责的是强化人类的正面回应”,杜克大学犬类认知中心主任布莱恩·哈尔通过电子邮件向大西洋月刊表示,“但目前的情况表明,这些面部表情发端于狗和狼分道扬镳之后。”  

By evolutionary standards, the time sincethis split has been remarkably short for two new facial muscles to havedeveloped. For a species to change that quickly, a pretty powerful force mustbe acting on it. And that’s where humans come in. We connect profoundly withanimals capable of exaggerating the size and width of their eyes, which makesthem look like our own human babies and “hijacks” our nurturing instincts.Research has already demonstrated that humans prefer pets with more infantlikefacial features, and two years ago, the authors of this latest study showedthat dogs who made the facial movement enabled by the RAOL and LAOM muscles—anexpression we read as distinctly humanlike—were more likely to be selected foradoption from a shelter than those who didn’t. We might not have bred dogs forthis trait knowingly, but they gained so much from having it that it became awidespread facial feature. “These muscles evolved during domestication, but almostcertainly due to an advantage they gave dogs during interactions with humansthat we humans have been all but unaware of,” Hare explained.

以演化的标准来看,从这次分道扬镳到发育出两块新的面部肌肉所用的时间惊人得短。对于一个演变如此迅速的物种来说,必然有一种相当强大的力量一直作用于它。而那就是人类的入场。我们和能够扩张眼睛大小和宽度的动物建立了深刻的联结,这种能力使它们看上去像我们人类的婴儿,并“挟持”了我们的哺育本能。研究已经证明,人类更喜欢拥有更多稚态面部特征的宠物,而就在两年前,这项最新研究的作者们向我们展现出的是:做出由眼角外侧牵缩肌和眼角内侧上提肌肇发的面部运动的狗,相比不做这些运动的狗,从收容所中被挑走收养的可能性更大。可能我们并不是因为明知这种性状的存在才去养狗的,但它们从这种性状中的获益如此之大,以至于它变成了一种普遍的面部特征。“这些肌肉是在驯化期间演化出来的,但这几乎毫无疑问是因为它们赋予了狗狗在和人类互动中的一种优势,而这是我们人类几乎没有意识到的”,哈尔解释道。

“It’s such aclassically human system that we have, the ways we interact with our owninfants,” says Angie Johnston, an assistant professor at Boston College whostudies canine cognition and was not involved with the study. “A big themethat’s come out again and again in canine cognition and looking at thedomestication of dogs is that it seems like they really just kind of dove rightinto our society in the role of being an infant or a small child in a lot ofways. They’re co-opting existing systems we have.”

“我们和自己婴儿的互动方式是如此古典的一套人类系统”,安吉·约翰斯顿说,她是波士顿大学研究犬类认知的助理教授,没有参与这项研究。“在犬类认知和狗类驯化研究中反复出现的一个重大主题就是:似乎,它们是真的以一个在很多方面都是婴儿或小孩的角色化入了我们的社会。它们正在成为我们现存系统的新成员。”

The same humanlike facial gestures couldalso be a dog’s way of simply securing attention in the first place. Eyebrowraising is one of the most well-understood examples of what researchers callostensive cues, a family of nonverbal signals (often facial movements andexpressions) humans send one another to convey their intention to directlycommunicate. Dogs’ uncanny ability to mimic this human expression likely leadsus to project certain human emotions onto them in ways we don’t with otheranimals, regardless of what they might actually be feeling.

这种很像人的面部姿态,可能从一开始就是一条狗确保关注度的方法。扬眉是被研究者们称为“明示的暗示”的最容易理解的例子之一,这是非语言信号(通常是面部运动和表情)其中的一族,人类为了直接交流,会互相发送这种信号以传达其意图。狗的这种模拟人类表情的神秘能力,可能会致使我们把特定的人类情感投射在它们身上,而这种方式我们和其他动物之间是不会发生的,无论它们真正感受到的为何。   

The movement of the RAOL and LAOM musclesis particularly open to interpretation. “In different contexts we’ll call thatsomething different,” says Alexandra Horowitz, a senior research fellow at theBarnard College Dog Cognition Lab. “In one case, I might say it’s sad, but inanother case I’ll say, He’s really paying attention. It can look wry, like aquestioning or unbelieving look.” According to Horowitz, dogs are the onlyanimals aside from our primate cousins that are expressive in this eerilyfamiliar way. Horses alone share the ability to twist their eyes into the samedoleful shape, but their overall expressions don’t strike us as humanlike inthe same way that dogs’ do. With dogs, Horowitz points out, we’re so driven toconnect that we often search for “smiles” in the shapes of dogs’ mouths. Thenew research, she says, “makes me think it’s more about being able to move theface in a way that humans move the face. We don’t like unexpressive faces.”

眼角外侧牵缩肌和眼角内侧上提肌的运动,尤其可以有多种解读。“在不同的背景中,我们对某件事物的称呼也会有所不同”,亚历山德拉·霍洛维茨说,她是巴纳德学院狗类认知实验室的高级研究员。“在某个案例中,我可能会说它是在伤心,但在另一个案例中,我会说它是真的在集中注意力。它看起来可能是揶揄的感觉,像是一种质疑或不相信的神色。”根据霍洛维茨的说法,狗是除了我们的灵长目表亲以外,仅有的一些以这种让人熟悉到带点怪诞的方式表情达意的动物。马也具备这种能力,能扭转眼睛呈现出哀伤的样子,但总体上它们的表情不会因为像人而如狗那般打动我们。就狗来说,霍洛维茨指出,我们主动去建立勾连的意愿是如此强大,使得我们常会在狗嘴的形状上寻找“笑容”。她说,这项新研究“让我想到,更重要的是有能力像人类那样去活动脸部。我们不喜欢缺乏表情的脸。”  

Both Horowitz and Johnston suggested thatsimilar studies looking at populations of dingoes (which Johnston researches)and Siberian foxes could provide yet another time capsule of sorts forunderstanding eyebrow movements and other evolutionary traits. Both specieslive near humans and are some of the closest living relatives to the earliestdogs. Why did they stay wild while dogs drifted into domestication? “Anythingto do with getting to the bottom of why we as a species picked out this oneanimal can carry a huge amount of information,” Horowitz says. “In some ways,it’s discovering something about ourselves.”

霍洛维茨和约翰斯顿都提出过,研究澳洲野犬(这是约翰斯顿在研究的)和西伯利亚狐狸种群的类似研究,还可以提供各式各样的有助理解眉部运动和其他演化特征的时间胶囊。这两个物种都生活在靠近人类的地方,而且都是和最早出现的狗关系最近的亲戚。它们为什么一直处于野生状态,而狗却不知不觉被驯化了?“对于为什么我们作为一个物种会拣选出这一种动物,任何形式的追根究底都裹挟着大量的信息”,霍洛维茨说。“它在某种程度上,正在发现一些关乎我们自身的东西。”

评论区:

1、Meanwhile, catsstill don’t give a fuck.

与此同时,猫儿们还是鸟都不鸟你。

2、"It’s the firstbiological evidence scientists have found that domesticated dogs might haveevolved a specialized ability used expressly to communicate better withhumans."
I don't think this has anything to do withevolution at all. While dogs may use these traits to their advantage, it ishumans that are ultimately breeding the traits that they consider mostappealing.

“这是科学家们找到的第一个生物学证据,证明了已经驯化的狗可能已经演化出了一种特别的能力,专门用来和人类更好地沟通。”
我不认为这和演化扯得上任何关系。虽然狗也许会利用这些特征谋求优势,但终究是人类培育出了这些在他们心中最吸引人的特征。

3、Well wouldn't thatstill be evolution through artificial selection?

好吧,那不还是经由人工选择的演化吗?

4、Yeah, that's myimpression. If humans had already befriended dogs, developing new facialmuscles would seem to offer little evolutionary advantage.

是的,这也是我的印象。如果人类已经成为了狗的朋友,发育出新的面部肌肉似乎并不能提供多少演化中的优势。

5、Not a surprise.We've turned wolves into some pretty horrendously inbred creatures. The fullbred ones, at least.

这也并不意外。我们已经把狼转变成了某种相当可怕的、近亲交配出来的生灵。至少也是完全由(人工)培育出来的。

6、That was superinteresting! Thanks!

这个超有趣的!多谢了!