Text 1

Morals, Apes and Us

Marc D. Hauser

    A female gorilla was seen helping an unconscious 3-year-old boy. Why did she do that? Did she feel empathy? Can animals learn to share, cooperate, punish, and show empathy? The following article tries to answer such questions.

    Nearly four years ago, a visitor to Brookfield Zoo, outside Chicago, captured an extraordinary event on video. A 3-year-old boy fell into a gorilla enclosure and was knocked unconscious. Within moments, Binti Jua, a female gorilla, approached, picked up the unconscious boy, and cradled him in her arms. Then she walked over and gently put the boy down in front of the caretaker's door. The event captured the nation's heart as newspaper headlines blared: "Gorilla Saves Boy."

    Most reports suggested that Binti rescued the boy because she felt empathy for him. Although there is no ambiguity about what the gorilla did, there are a lot of questions about why. Did she realize the boy was unconscious? Was she concerned about his well-being? Would she have acted in the same way toward a conscious boy, a cat, a teddy bear, or a bag of potato chips?

    Despite what the headlines implied about Binti's moral fiber, the answer is by no means clear. Studies by developmental psychologists Susan Carey and Frank Keil, for example, have shown that children don't fully grasp the distinction between a dead being and a live one until they are almost 10 years old. And to date, no study of ape intelligence comes close to showing that orangutans, gorillas, or chimpanzees have the mental sophistication of a 10-year-old human. We can only guess why Binti did what she did. And one incident is not enough to warrant conclusions.

    But Binti's actions do raise the public and scientific interest in the broad question of what mental traits cause us to behave morally and to what extent other animals possess those tools. As a psychologist, I'm interested in the techniques we use to get at these questions: Can other creatures share, cooperate, punish cheaters, show empathy, and act altruistically?

    In a 1988 study, University of Zurich ethnologist Edward Stammbach set up an experiment with long-tailed macaque monkeys to test their ability to rein in aggressive behavior and act cooperatively. First each monkey was trained to press a lever on a machine to receive a popcorn treat. Once each animal knew what to do and when, subgroups were created. Then a low-ranking member in each subgroup was trained to press a set of levers in a specific sequence that caused the machine to deliver enough popcorn for three individuals. During the training, the machine began releasing popcorn only to the low-ranking specialist.

    At first, high-ranking individuals threatened low-ranking individuals to keep them away from the dispenser altogether. Then the high-ranking individuals learned that the low-ranking individuals had a unique skill, so they followed them to the machine and waited to grab all the popcorn. Before long the low-ranking specialists stopped operating the machine. But their strike didn't last long. Some higher-ranking individuals changed their behavior. Rather than chasing specialists away or eating all their popcorn , they began to inhibit their aggression. They approached peacefully and allowed the lower-ranking specialists to eat a portion of the popcorn. Further, some high-ranking individuals started grooming specialists more often, even during periods when the machine was inoperative. Although this attitude change enabled low-ranking specialists to access food that would normally be unobtainable, it had no impact on their dominance rank within the group. Specialists kept their low rank but were allowed a moment at the high table when their skills were of use to the royalty.

    Other experiments have found that monkeys even have a rudimentary sense of ownership and respect for property. Although these might seem to be strictly human concerns, territorial animals such as sunfish, lizards, sparrows, ad gibbons are invested in these issues. The space that a territory owner defends is like its property, and an intruder's respect reveals its acknowledgment of ownership and property rights.

    In a 1991 study, for example, University of Zurich ethnologists Hans Kummer and Marina Gords tested macaques that had something other macaques wanted─a see-through tube filled with raisins. The tube was either fixed to a wall or freestanding. If it was freestanding, it was attached to a long or a short piece of rope, or no rope at all. A subordinate animal was allowed first crack at the tube in all the various placements. Then researchers observed how the more dominant individuals reacted. Although dominants often take resources away from subordinates, the experiments revealed rules underlying their responses. Consistently, dominants took ownership of fixed tubes more often than free tubes, and took over free tubes when the subordinates failed to carry them. Staying close to the tube and looking at it were not sufficient cues of ownership from the dominant's perspective. A dominant macaque would appear to inhibit its impulse to grab the tube if a subordinate held it close to its body. Here, then, is an intriguing example of how inhibition plays a crucial role in maintaining social conventions among monkeys.

    But in any social situation with conventions, individuals often find that it pays to break the rules. Would such rule-breakers be punished? To explore this possibility, I conducted experiments on the island of Cayo Santiago, a research station near Puerto Rico that is home to some 800 rhesus monkeys. This particular species has an interesting convention: Unlike long-tailed macaques, which don't share food, the rhesus monkeys tend to call out when they find food. In the study, my colleagues and I located lone individuals and presented them with a small stash of food. Their first response was to look around, presumably to decide if there were enemies near. A few individuals waited and waited and then, as if assuming an infantry combat crouch, moved cautiously toward the food. Only half the discoverers called out. When they were detected by other group members, some were aggressively attacked. Our initial suspicion was that those who were being attacked were lower-ranking than those who were not. This hunch turned out to be false. Surprisingly, both high- and low-ranking individuals were attacked. Whether or not they were attacked seemed to depend on their vocal behavior. Silent discoverers who were caught with food were attacked more often and more severely than those who cried out. It was as if individuals were being punished for being inappropriately silent, for deceptively withholding information about a rich food source.

    In a second experiment, we tested peripheral males, outsiders shifting between groups. Of 26 outsider males who were shown food, not one called out. They beelined to the food and either consumed it on the spot or gobbled a few pieces and then moved to a new location with a stash. Even if other monkeys discovered them with the food, the outsiders were never attacked. Thus, it seemed that members of an established rhesus community abide by a rule that says: Attack members that find food and don't share it. And the corollary seems to be: Why bother risking harm by assaulting onetime transgressors?

    Thus research indicates that animals can inhibit their impulses and punish those who violate community rules. But what about empathy? What about Binti? Unless we can establish that animals understand the thoughts and feelings of others, we cannot assume that their behavior is moral as humans understand the word. Codes of moral behavior are founded on beliefs of right and wrong. How we form those beliefs is based on an idea of justice, a consideration of how particular actions affect others. And to understand how our behavior affects others requires empathy.

    Ethnologist Frans de Waal has offered several observations of apparent empathy among nonhuman primates in his 1996 book Good Natured: The Origins of Right and Wrong in Humans and Other Animals. Richer insights come, however, from a series of studies published about 40 years ago, when standards for animal welfare were minimal. Today the experiments would be deemed unethical, but they do provide a window on animal emotion that has yet to be opened by more recent scientific observations.

    One experiment was designed by psychologist Robert Miller and his colleagues to see if a monkey could interpret another monkey's facial expression, a presumed indicator of emotion. First, a researcher trained rhesus monkeys to pull a lever to avoid getting shocked after hearing a specific sound. Then one of the monkeys─the "actor"—was put in a room with a lever and a live television image of a second animal—the "receiver"─that was out of sight and earshot. The receiver was exposed to the sound that indicated a shock was coming but lacked a lever to avoid it.

    The assumption underlying this experiment was that the receiver would hear the sound, anticipate the shock, and show fear on its face. If the actor understood the receiver's facial expressions, then it would use this information to pull its lever. If the actor failed, both animals received a shock. Because shock trials were presented randomly, and neither animal could hear the other, there was no way to predict the timing of a response except by using the receiver's image in the monitor. As it turned out, the actor pulled the lever significantly more when the receiver heard the sound. Miller concluded that the actor was able to read the receiver's facial expressions. Moreover, he and his colleagues suggested that the animals behaved cooperatively: To avoid the shock, the receiver gave a signal and the actor read the receiver's signal.

    Did the receivers intend to provide information to the actors? Was this a cooperative effort? The receivers, to be sure, must have felt helpless and afraid. But to establish that they were signaling the actors, one would have to demonstrate that they were aware of the actors' presence. And, given the design of the experiment, they certainly were not. Rather, each receiver's response was elicited by the sound, perhaps as reflexively as we kick out our foot in response to the doctor's tiny mallet. It seems likely that the actors picked up on a change in the activity of the receivers, one that was consistent enough to predict the shock. But using an expression to predict a response is not the same as seeing the expression as an indication of another's emotions at the time.

    This experiment left many loose ends. Although it is clear that rhesus monkeys can learn to avoid shock by attending to a facial expression, we don't know if this response is motivated by empathy, and empathy is necessary for altruism. One has to feel what it would be like to be someone else, to feel someone else's fear, pain, or joy. We don't know whether the actors were even aware of the receivers' feelings. There was no reason for the actors to care. From the actors' perspective, all that mattered was that the image displayed on the video monitor functioned as a reliable predictor of shock. A better experiment would have allowed the actors to see what was happening to the receiver but restrict the shock to the receiver alone.

    In a 1964 study, Jules Maserman and his colleagues ran a different experiment, again with rhesus monkeys. An actor was trained to pull one of two chains to receive its food in response to a brief flash of blue or red light. Next, a receiver was housed nearby, where the actor could see it. The experimenter then changed the consequences of responding to the color of the flash. Pulling in response to one delivered food; pulling in response to the other delivered both food to the actor and a severe shock to the receiver. Most actors pulled the chain delivering the shock far less often than the chain delivering food only. Two of the 15 actors even stopped pulling both chains for between 5 to 12 days. When the actors were paired with new receivers, most continued to refrain from pulling the chain that delivered the shock. And pairs that knew each other well tended to show more altruistic behavior than pairs that were unfamiliar.

    What is most remarkable about this last experiment is the possibility that some monkeys refrained from eating to avoid injuring another. Perhaps the actors empathized, imagining what it would be like to receive the shock. Alternatively, perhaps seeing another monkey grimace in pain is unpleasant or threatening, and rhesus monkeys will do whatever they can to avoid unpleasant conditions. Or perhaps the actor worried that one day it might be the recipient of a shock. Although refraining from eating appears to be a response of empathy or sympathy, it may actually be a selfish response.

    As the experiments show, animals are by no means robots driven solely by instinctual responses. They are sensitive to their social and ecological environments, and under certain conditions they can inhibit one response and favor another. Moreover, they can punish others and sometimes alleviate another's pain. But no experiment to date has provided evidence that animals are aware of others' beliefs or intentions. And without such awareness, there can be no ethical judgment.

    Asking what it means to be moral challenges us to think about how our own capacity for moral agency came about. Monkeys employ rulelike strategies for promoting the welfare of a group, including maintaining peace, observing boundaries, and sharing food. And they can abide by these rules without necessarily understanding them. Humans are a different kind of animal: We can consciously evaluate whether behavior is right or wrong, but we tend to do so depending on the conventions of our society. In that regard, the roots of our moral intuition are entwined with the self-interest shown by other animals. What we don't know is exactly when the uniquely human capacity for empathy and justice emerged in our ancestors and how cultures build on a universal moral sense. What is certain is that our moral potential is still far from fully realized. As Agesilaus, a Spartan king, said, "If all men were just, there would be no need of valor."

 TOP

课文一

道德、猿和我们

马克　D·豪泽

    有人看见一只雌性的大猩猩救助一个不省人事的3岁男童。她为什么那样做？她是否也有同理心？动物能学会共享、合作、惩罚以及表示出同理心？下面的这篇文章试图回答这个问题。

    将近四年前，一个芝加哥郊外布鲁克菲尔德动物园的游客，用摄像机拍下了一个令人惊讶的事情。一个3岁的男孩掉进了大猩猩的围场里，失去了知觉。一会儿，宾蒂·朱叶，一只雌性大猩猩，走了过来，抱起了这个失去知觉的男孩，把他搂在怀中。然后她走过去，把男孩轻轻地放在管理员出入的门口。报纸大幅标题赫然标着：“大猩猩救男孩，”这件事轰动全国 。

    大多数报道认为，宾蒂救那个男孩，是因为她对他的处境进行了换位思考。尽管大猩猩做的事情确凿无疑，她为什么要这样做，还有许多疑问。她是不是意识到孩子不省人事？她是不是关心他的安危？对一个有知觉的男孩，一只猫，一个玩具熊，或者一袋土豆片，她也会这样做吗？


    不管报纸的标题怎样暗示了宾蒂的道德素质，答案绝非是清楚的。例如，发展心理学家苏珊·凯里和弗兰克·凯尔的研究表明，小孩快10岁时才能完全识别死东西和活东西的区别，而且到今天为止，没有一项猿类智能研究能够大致表明，猩猩、大猩猩或是黑猩猩具有一个10岁的人的智力水平。我们只能猜测为什么宾蒂那样做，而且，一次偶然的事件也不足以保证结论正确。

    但是宾蒂的行为确实引起了公众和科学界对这个大问题的兴趣：什么智力特点引起我们符合道德地行动，多大程度上别的动物也具有这些工具？作为一个心理学家，我对我们用来解答这些问题的方法很感兴趣：别的生物也能够共享、合作、惩罚骗子、表现同理心以及无私地行动吗？


    在1988年的一项研究中，苏黎世大学的人种学者爱德华·斯塔姆贝奇对长尾猕猴进行了一次试验，以测试它们控制攻击性的行为和相互合作的能力。首先，每只猴子都接受一种训练，按一下一种装置上的杠杆，就能得到一把爆米花。当每个猴子都学会做什么以及什么时候做时，就把它们分成更小的组。然后训练每小组中一个地位低的成员去按一系列扛杆，这些扛杆以特定次序排列，能使装置倒出足够三个猴子吃的爆米花。在训练中，装置开始只给这个地位低的“专家”放出爆米花。



    起初，地位高的猴子威胁地位低的猴子，要它们一直远离爆米花箱。随后，地位高的猴子才知道，原来地位低的猴子有一种独特的技巧，于是它们就跟着地位低的猴子来到装置前，等着攫取所有的爆米花。不久，地位低的“专家”不再操作那个装置。但这个罢工没有持续多长时间。一些地位高的猴子改变了它们的行为。它们不再把地位低的“专家”赶走或是吃掉所有的爆米花，霸道行为开始有所收敛。它们安静地走近，允许地位低的“专家”吃一份爆米花。不仅如此，一些地位高的猴子开始更经常地为地位低的“专家”梳理毛发。尽管这种态度的转变使地位低的“专家”能够吃到它们通常无法得到的食物，它在小组里对它们的上司并没有什么影响。“专家”的地位依然很低，但是当它们的技术对权威者有用时，就允许坐在上席餐桌。

    其它试验还发现，猴子还有一种初步的所有权观念和对财产的尊重。尽管这些看起来全是人类所关心的事情，然而有地盘感的动物如翻车鱼、蜥蜴、麻雀和长臂猿都有这些问题。一个地盘的所有者护卫的空间，就好像是它的财产，一个外来者对他者地盘表示尊重，就表明了它承认所有权和财产权。

    例如，一项1991年的研究中，苏黎世大学人种学者汉斯·库马和玛丽娜·戈兹对一种猕猴进行实验，这些猕猴有某种别的猕猴没有的东西——一个装满葡萄干的透明管子。这个管子或者被固定到墙上，或者自个儿立着。如果是自个儿立着，它被系在一根或长或短的绳子上，或者干脆不系绳子。一个地位低的猕猴被允许首先去打开放在各种不同地方的管子。然后研究者们观察占优势的猕猴如何反应。尽管占优势者经常从下属那里抢走物品，试验揭示了它们的反应后面的潜规则。情况总是这样：占优势者更经常地拿走固定的管子，而不是自个儿立着的管子；当下属猕猴没有拿时，才去拿自个儿立着的管子。在占优势的猕猴看来，站在管子旁边看着它并不足以表明拥有它。如果一个下属猕猴把一个管子紧靠身子抱着，那么占优势猕猴就会抑制住自己想去抢走管子的冲动。这个有趣的例子表明，抑制自我在猴子们保持社会规范方面是如何起关键作用。

   但是，在任何有规可依的社会环境中，个体常常发现违犯规则是要付出代价的。这种违犯规则者会受到惩罚吗？为了探寻这种可能性，我在凯酉·圣地亚哥岛进行了试验 。该岛是邻近波多黎各的一个研究站，上面生活着大约800个恒河猴。这种特别的猴有一个有趣的习俗:和不分享食物的长尾猕猴不一样，这些恒河猴在发现食物时总是大声叫喊。在研究中，我和我的同事们选定一些独处的猴子，给它们少许食物。它们的第一反应是四下看看，大概是想断定附近有没有敌人。少数的猴子一直在等待，最后，好像是摆出一副步兵格斗的架势，小心翼翼地朝食物移动。只有一半发现食物的猴子叫喊。当它们被别的小组成员发现时，有些就会受到狠狠的攻击。我们最初猜疑，那些受到攻击的猴子比那些没有受到攻击的猴子的地位要低。结果证明这种预测是错的。令人吃惊的是，地位高和地位低的猴子都受到了攻击。它们是否受到攻击，要看它们有没有叫喊。发现食物而不吭声的猴子比那些叫喊的猴子遭到更经常、更凶狠的攻击。似乎，那些猴子受攻击，是因为它们不适当地保持沉默，隐瞒了一个丰富的食物资源的信息。

    在第二次试验中，我们对外围的雄性猴子进行试验，它们是在不同群体之间流动的外来者。在26个外来雄性猴中，给予它们食物时，没有一个叫喊。它们直奔食物，要么当场把它吞下，要么抓上几块后带着跑到一个新地点。即使是被发现带着食物，外来者也从不会遭受猴群的攻击。看起来一个稳定的恒河猴群体的成员们遵循着这样一条规则：攻击那些发现食物而不与大家分享的成员。答案很自然，那就是：为什么要冒险去进攻那些一时的侵犯者呢？

    这样，研究表明，动物能够抑制它们的冲动，惩罚那些违反社团规则的成员。但是怎样说明同理心？怎样说明宾蒂的事例？除非我们能够证实动物理解他者的思想和感情，我们就不能假定它们的行为像人类所理解的那样是道德的。道德行为的规则是建立在对与错的信念之上的。我们如何形成这些信念基于一种正义观，一种对特定的行为如何影响别人的考虑。要理解我们的行为如何影响别人，这需要同理心。

    人种学者弗郞斯·德·瓦尔在其1996年出版的《善良的：论人类和其它动物中正确与错误的根源》一书中，提供了几起观察到的非人类的灵长类动物中明显的同理心例证。然而，更为深入的了解来自40年前发表的一系列研究成果，当时动物的待遇水平还处在最小的限度。今天，这些试验会被认为是不道德的，但在了解动物感情的研究方面，它们确实为我们提供了一扇窗户，有待时间较近的科学观察将其开启。

    有一项实验是由心理学家罗伯特·米勒和他的同事们设计的，用来了解一只猴子是否能够理解另一只猴子的面部表情，即人们认为的感情显示器。首先，一位调查者训练恒河猴在听到一种特定的声音后拉一根扛杆来避免电击。然后其中一只猴子——“作用者”——被关进一个房间，里面有一根扛杆，还有他看不见也听不见的第二只猴子——“接受者”——的现场电视图像。接受者能听到电击将要到来的声音，但却没有扛杆来避免它。



    进行这项实验的假定理论是，接受者会听见声音，预料到电击的到来，脸上会显露出害怕。如果作用者理解了接受者的面部表情，它就会利用这个信息来拉动扛杆。如果作用者不这么做，两只猴子都要受到电击。由于电击试验是随机的，而且两只猴子都听不到对方，所以没有办法预测反应的时间，只有看显示器上接受者的图像。结果，当接受者听到声音时，作用者拉动扛杆的次数明显增多。米勒下结论说，作用者能够看懂接受者的面部表情。而且，他和他的同事们还提出，两只猴子表现得很合作：为了避免电击，接受者发出一个信号，表演者看懂了这个信号。






    接受者是否想要给作用者提供信息？这是一种合作吗？接受者当然一定感到了无助和害怕。但要想认定它们在向作用者发出信号，我们得证明它们意识到作用者在场。而就实验的设计来说，它们当然不会意识到。倒不如说，每个接受者的反应是由声音引发的，就像医生用小槌棒敲时我们会往外踢腿一样条件反射。看起来可能是作用者在接受者的行动中对某一个变化熟悉了起来，这个变化相当有规律，可以用来预测电击的到来。但是，通过一个面部表情来预测一个反应，与把面部表情看作他者的感情显示是不一样的。

    这项实验留下了许多未解决的问题。尽管很明显，恒河猴能够通过观看面部表情来学会避免电击，我们不知道这个反应是否是由同理心引起的，而对利他主义来说，同理心是很必要的。一个人得感受是别人的话会是怎样，得感受别人的惧怕、痛苦，或者欢乐。我们不知道作用者是否也意识到了接受者的感情。作用者也没有理由在乎这些。从作用者的角度看，要紧的是显示在电视屏幕上的图像，其作用是可靠地预测电击。更好一点的实验，应该是让作用者看到接受者发生了什么事，但是把电击限于接受者身上。

    在1964年的一项研究中，朱尔斯·梅瑟曼和他的同事们进行了一项不同的实验，这次也是用恒河猴来做的。一个作用者接受训练，对一道闪过的蓝色或红色的光做出反应，拉动两个链条中的一条以得到食物。接着，一个接受者被安置在作用者可以看到的附近。实验者然后改变对闪光的颜色做出反应的结果。看到一种颜色拉动链条得到食物；看到另一种颜色拉动链条，既能得到食物，又会给接受者带来一阵强烈的电击。大多数的行动者拉动带来电击的链条的次数，比拉动只带来食物的链条的次数要少得多。15个表演者当中，2个甚至有5到12天没再拉两个链条。当行动者与新的接受者搭档时，大多数继续不去拉带来电击的链条。相互非常熟悉的搭档，比不熟悉的搭档，趋向于显示更多的利他主义行为。





    这最后一次实验最引人瞩目的地方是，是有可能有些猴子为了避免伤害另外的猴子而不去吃食。或许作用者感受了同理心，想象到受电击会是什么感觉。另外一种可能性是，看到别的猴子面露痛苦是不愉快或带有威胁性，恒河猴会尽其所能地避免不愉快的情况。或者作用者担心有一天它也会是受电击的对象。尽管不去吃食似乎是一种同理心或同情心反应，它实际上可能只是一种自私的反应。

    就像试验显示的那样，动物绝不是机器人，只受本能反应的驱使。它们对其社会和生态的环境都很敏感，在某些情况下，它们能够抑制一种反应而偏向另一种。而且，它们会惩罚别的动物，有时会减轻别的动物的痛苦。但到目前为止，没有任何实验能够证明，动物清楚其它动物的看法或意图。没有这方面的意识，就不可能有道德上的判断。




    有道德感意味着什么?这个问题促使我们思考我们自己的道德行为的能力是如何来的。猴子们利用类似规则的方法来增进一个团体的福利，包括保持和平，遵守边界和共享食物。它们不必理解这些规则就能遵守。人类是一种不同的动物：我们能够有意识地评价一种行为是对还是错，但是我们这样做往往依我们社会的习俗而定。在这点上，我们道德直觉的根源和其它动物所显露出来的利己主义交织在一起的。我们所不知道的是，到底是什么时候我们祖先已经有了感受同理心和正义的独特能力，文化是如何建立于一种普遍的道德感之上的。但可以确定的是，我们的道德潜力还远远没有被充分认识。正如斯巴达国王阿杰西劳斯所说，“如果每个人都是正直的，勇猛就没有必要。”

返回

Text 2

Pepperberg's Parrots

by Mark Caldwell

    Alex, age 23, and Griffin, age 4, are hell on decor. Thanks to them, the laboratory-cum-home of these impish African Grey parrots looks as if a miniature tornado has blown through. Strewn about are pieces of fruit from discarded snacks, mangled toys, and a huge mound of cardboard cartons demolished with great relish by Alex.

    Animal behaviorist Irene Pepperberg, the birds' caretaker, maintains an amused tolerance about her two charges, partly because they have richly rewarded her serious scientific inquiry into the intelligence of animals. For more than 20 years, her research has implicitly challenged the idea that humans alone are capable of real thought and real communication. In a series of experiments that withstand rigorous and even hostile scrutiny, Alex and Griffin have shown themselves intelligent enough to comprehend and juggle abstract images of the objects that make up their world─skills once thought to be the exclusive property of humans.

    Under Peperberg's tutelage, the parrots have learned to speak English so clearly they'd delight even a fussy speech expert. But the value of this work goes far beyond experiments in voice training. These parrots aren't just parroting─they associate specific words with specific objects, and they have learned to identify a number of different colors, shapes, and materials. Show Alex two triangles, one yellow and one blue, and ask him what's the same about them. He’ll answer, "Shape." Ask him what's different, and he'll say, "Color!"

    Until Pepperberg began this research in the 1970s, few scientists had studied intelligence in parrots, and few do today. Most inquiries have instead focused on monkeys, chimpanzees, gorillas, and dolphins, all of which are much more difficult to raise, feed, and handle. Pepperberg especially likes parrots because, like humans, they're smart, long-lived (often up to 50 years), social animals that depend on communication for survival. And, best of all, to communicate with people, parrots don't need devices built with buttons to push, and they don't need to be taught sign language: They can learn to speak. Nobody knows why parrots can do this, or exactly how they do it. But they can clearly get their two cents in despite having a brain the size of a walnut.

    Even the most skeptical visitor to Pepperberg's lab is sure to be taken aback by what the birds can do. When Alex, for example, wants to visit a favorite atrium near the lab, he orders, "Go see tree!" And some of his communications are fresh—new words and phrases he hasn't been taught. Once, for example, as two of his student trainers prepared to leave the lab at the end of the day, Alex admonished: "You be good. See you tomorrow!"

    It's not just what the parrots say that makes them seem eerily human; it's the level of intelligence they easily demonstrate. Consider Griffin's performance on a test Pepperberg devised to see whether the birds could use a mirror image of an object to manipulate it. Children don't typically master that skill until they're 3 years old. In the experiment, a nut is concealed underneath the lid of a box. The nut is attached to a wire that runs up through a slit in the lid and connects to a paper clip for the parrot to yank. The slit branches out into three tracks, each of which ends in a hole through which the nut can be pulled. The trick is that two of the three slits are blocked by obstructions that can only be seen by looking in a mirror that reflects a backward view of what's inside the box. Most humans who try to solve the puzzle are baffled, but Griffin, watching intently from his perch on the lab counter, will demand to be brought over, peer into the mirror for perhaps half a second, triumphantly zip the nut down the right track, jerk it up through the opening, and grab it.

    Although Irene Pepperberg has always loved animals, she chose chemistry as her field in graduate school at Harvard University. There, in the early 1970s, she happened to see a television documentary about how animals learn. Like a number of researchers at the time, she became fascinated by the question of just how smart animals are and whether they can learn to communicate with humans. While finishing up her chemistry degree, she began taking courses in animal behavior, psychology, and communication. In 1977 she acquired 1-year-old Alex. He became the center of her research in a small lab at Purdue University.

    Much of the animal-intelligence research of that era ultimately foundered before an onslaught of skeptics. Most notable was Washoe, a chimpanzee who became world-famous for her apparent mastery of American Sign Language. But observers of Washoe objected that the researchers who worked with her were giving subtle cues and generously interpreting ambiguous gestures as signs for words. "It's so easy to overinterpret when you have a bird that says, ‘I’ll see you tomorrow,"says Pepperberg."I’ve got enough anecdotal data like that to fill a book. But what's really referential?" What, in other words, constitutes proof that the bird knows what it is saying? The history of science is littered with animals that seemed to be displaying extraordinary brainpower but were just responding to unconscious prompts from owners and trainers.

    To avoid such pitfalls, Pepperberg designs experiments with the care of a hard-nosed skeptic. For example, when an experiment demands that Alex learn a new word like "none," Pepperberg waits until the parrot's pronunciation is so unambiguous that different observers agree 90 percent of the time on what he's saying. That ensures that an experimenter eager for Alex to succeed won't mishear a slurred random utterance as a correct answer. She also strives to avoid the possibility that a correct response is merely conditioned─automatic behavior generated by the anticipation of a reward. So experimenters vary their repertoire of questions to make sure that Alex is responding to the content of the question and making intelligent discriminations. And to avoid the possibility that the experimenter's body language might be prompting Alex's answers, students who test Alex are never the same ones who taught him the words and concepts involved. As a result, Pepperberg's work has won accolades for its persuasiveness from the likes of Oxford University animal behaviorist Marian Stampl Dawkins, an authority on animal consciousness and a skeptic about many studies in the field.

    Sometimes, human error offers the birds an opportunity to show how smart they are. Roughly 5 percent of the time, for example, student questioners slip up and scold Alex with a "No!" when he has in fact given the correct answer. When this occurs, Alex tends to stick to his guns and repeat the correct answer. Eventually the examiner comes to her senses, and Alex gets the reward he deserves.

    Pepperberg is careful to point out that such experiments have stimulated Alex and Griffin to master intellectual tasks both far different from─and possibly harder than —those they might achieve in the wild. And that is perhaps the most promising aspect of her research in the long term. "I don't want to say they're learning English," she says, "because we can't get inside an animal's brain, and we can't know if its experience of English is exactly the same as ours. But they have learned a communication system that's completely alien to them." She argues that this achievement alone is significant─and not just because it challenges dogma about animal intelligence. The way she has trained parrots to master skills outside their natural repertoire─which she calls "exceptional learning"─also serves as an interesting model for human instruction.

    Her training technique is interactive, using a model/rival mode. And it is simple: Both animals and people learn more readily when they can observe and even compete with others learning at the same time. The best results come if, rather than being harangued by a teacher, the pupil watches a tutor coaching someone else. The pupil learns by noting that the teacher rewards the student for correct answers and gives rebukes for wrong ones. The technique, pioneered by Dietmar Todt at the University of Freiburg, Germany, in the 1970s, worked quickly when Pepperberg tried it with Alex. He caught on rapidly as she taught the undergraduate who served as a model. Alex began competing with the student for Pepperberg's attention and approval. The model/rival strategy worked so well for Alex that it has been successfully adapted for helping developmentally disabled children learn.

    By the late 1980s, Alex had learned the names of more than 50 different objects, five shapes, and seven colors. He's also learned what "same" and "different" mean─a step so crucial in human intellectual development that it has become a staple of Sesame Street shtick. Show Alex two objects of different shape, color, and material, and then ask him, "What's same?" He'll answer, "None!" Thus he appears to understand not only similarities and differences but also an even more abstract concept─absence. Alex has become so skilled that, in one of Pepperberg's projects, he has been promoted to the position of tutor. "We want to see if Alex can work as a tutor for Griffin," Pepperberg explains. "Partly we got Griffin to replicate our work with Alex, to prove he wasn't some kid of avian Einstein."

    To demonstrate, Justin, one of Pepperberg's undergraduate assistants, instructs Griffin and Alex to hop up on the work perch. As in many a human classroom, things get off to a balky start. Griffin seems cranky, insistently croaking, "Wanna go back." He has spent most of this morning idly shoving a metal spoon back and forth across the countertop and wants to return to the lab counter to play. Justin displays a ring and asks: "What toy, Griffin?" Griffin answers "Wood!" and Alex unhelpfully pipes up with "Rock! Rock! Rock!" A couple more trials follow, in which Griffin correctly identifies cork, wood, and wool (which he pronounces with a sirenlike flourish :"Wooh-ull!"). Alex sits taciturnly by. As the experimental session progresses, both Alex and Griffin seem to slide into the spirit of things, falling almost naturally into the model/rival mode. Justin displays a key and asks, "What toy?" Griffin doesn't answer at first, but when Alex barks, "Key!" Griffin follows suit. When Griffin doesn't respond to a toy truck, Alex chimes in with a quite fed-up-sounding "Truck! Truck!"

    Pepperberg's instructional techniques have been so successful that they've now attracted the interest of researchers in artificial intelligence. She recently worked with computer scientists at the Massachusetts Institute of Technology to help develop software that can learn or that can be used to help others learn. "It's a lot simpler to model a parrot's learning than a person's, " Pepperberg says. But she believes that computer software could be written to respond to—maybe even "learn" from─the interplay of correct answers and mistakes that makes up the model/rival system.

    Whether its promise is for people or computers, Pepperberg's research is forcing psychologists to rethink the boundaries between animals and humans. The thought processes of Alex and Griffin may approximate our own a lot or a little, says Pepperberg, but it's getting well-nigh impossible to deny their intelligence.

    A recent incident caught on videotape during a model/rival session illustrates the point: Griffin, while trying to say "paper," splutters "ay-uhr." Alex, seemingly pushed to the limits of his patience, peremptorily orders Griffin to "Talk clearly!"

(1904 words)  TOP

课文二

佩珀堡的鹦鹉

马克·考德威尔

    23岁的亚历克斯和4岁的格里芬简直是家居布置的克星。由于这俩精灵淘气的非洲灰鹦鹉作乱，它们的实验室兼居室，看起来就像有微型龙卷风吹过。地上到处是吃剩的快餐掉出来的水果片、撕裂的玩具以及一大堆被亚历克斯兴致勃勃毁掉的硬纸盒。

    动物行为学家艾琳·佩珀堡，这两只鸟的看护人，对它们表现出令人惊讶的宽容，部分是因为它们对她在动物智能方面的科学研究给予了丰厚的回报。二十多年来，她的研究一直潜在地挑战只有人类才能进行真正的思维和交流的观点。在一系列严格甚至苛刻的试验中，亚历克斯和格里芬都表现得相当聪明，能够理解和想象它们周围世界的抽象形体，而这一本领曾被认为是人类特有的。






    在佩珀堡的训练下，这两只鹦鹉说起英语来吐字清晰，即使是爱挑剔的演说专家也会被它们逗乐。但这项工作的价值远远超过了在声音训练方面的实验。这两只鹦鹉不只是在学舌――它们把特定的词语与特定的物体联系起来，还学会了识别许多不同的颜色，形状，和材料。给亚历克斯看一黄一蓝两个三角形，问其相同之处何在，它就会说，“形状。”问其不同之处何在，它就会说，“颜色！”



    佩珀堡20世纪70年代开始这项研究，在此之前，很少有科学家研究过鹦鹉的智力，就是今天也没有什么人研究。许多的研究都集中在猴子、黑猩猩、大猩猩和海豚身上，这些动物都比鹦鹉难饲养和难对付得多。佩珀堡特别喜欢鹦鹉，是因为像人类一样，它们是一种聪明、长寿（通常能活到50岁）、要依靠交流才能生存的社会性动物。而且，最大的好处是，与人类交流，鹦鹉不需要设有按钮的装置，也不需要教给它们手势语：它们能够学会说话。没人知道为什么鹦鹉能做到这一点，或它们究竟怎样学会说话的。尽管脑子只有胡桃那么大，它们还是能够清楚地表达自己的意见。




    甚至连那些最爱持怀疑态度的人，到佩珀堡的实验室来看一看，也肯定会为这两只鸟的表演大吃一惊。比如，当亚历克斯想到实验室旁它最喜爱的一个门廊去时，它就命令道，“去看树！”它说的一些话是新的——它还没学过的新词新句。例如有一次，它的两个学生训练员在一天结束时正准备离开实验室，亚历克斯告诫他们说，“你们要乖。明天见！”



    不仅仅是鹦鹉所说的话使它们看起来怪怪地有点像人类；还有它们轻松地表现出来的智力。看看格里芬在佩珀堡的一次试验中的表现，这次试验用来发现鸟类是否能够利用一个物体在镜子里的影像以操纵它。一般来说，儿童直到三岁才能掌握这个技巧。在实验中，一颗坚果被藏在盒子盖下。坚果系在一根穿过盒盖上一个开口处的绳子上，并连在一个纸夹子上好让鹦鹉拽。这个开口处又分成三道叉，每一道叉末端形成一个小洞，坚果可以通过小洞拉出来。问题难在这三道叉中有两道是被堵着的，只能通过镜子看盒子里面的倒影才能看出来。大多数试图解开这个机关的人都被难倒了，但格里芬从它站的实验室柜台处聚精会神地看了一会儿，就要求带它过去，它稍稍朝镜子里瞥了一眼，成功地顺着正确的通道拉出了坚果，猛地把它甩出开口处，然后一下子抓住。







    尽管艾琳·佩珀堡一直喜爱动物，她在哈佛念研究生时选的却是化学专业。在那里，70年代早期，她偶然看到一个有关动物如何学习的电视记录片。就像当时的许多研究者一样，她被动物有多聪明以及它们是否能和人类交流这个问题迷住了。在完成化学专业学位的同时，她开始选修动物行为、心理、交际方面的课程。1977年她得到了一岁大的亚历克斯。它成了她在珀杜大学一个小实验室的研究中心。





    在那个时代，许多对动物智力的研究最终都因敌不住怀疑论者的攻击而失败。最引人注意的是沃什欧，这是一个因能明显地熟练掌握美国手势语而闻名世界的黑猩猩。但是观看沃什欧的人反对说，它的研究者们在给它微妙的暗示，并非常泛地把模棱两可的姿势解释成代表某个意思。“当一只鸟对你说‘明天见’时，很容易对此做出过度的解释，”佩珀堡说。“像这样的事情我多得能写一本书，但哪些真正有参考作用？”换句话说，什么东西能证明鸟类知道它自己在说些什么？看起来有非凡的智力，但实际上只是在回应其主人或训练者无意识的提示。在科学史上，这样的动物多得是。

    为了避免这样的错误，佩珀堡以一个固执的怀疑论者的细心来设计实验。例如，当一个实验要求亚历克斯学会像“没有一个”这样的新词时，佩珀堡一直训练到鹦鹉的发音已经相当准确，不同的观察者对它说话90%的时间都一致认可才罢。这样就保证了急切想让亚历克斯成功的实验者，不会把一个任意的模糊音误听成正确的回答。她也竭力避免一个正确的回应有可能仅仅是条件反射――由于期望得到报偿而产生的机械性行为。因此实验者们不断变换问题，以确保亚历克斯是在对问题的内容进行回应和智力上做的区别。为了避免实验者的手势语言可能会给亚历克斯以提示，对亚历克斯进行实验、教给它生词和相关概念的学生从不是同一个人。结果，佩珀堡的研究令人信服，赢得了像牛津大学动物行为学者马丁·斯坦普尔·道金斯这样的专家的赞誉，此人是研究动物意识方面的一个权威人物，对该领域的许多研究都抱怀疑态度。

    有时，人的差错会给鸟类一个显示它们聪明的机会。例如，大约有5%的时间，提问的学生会说漏嘴，训斥亚历克斯说“错了！”而事实上他做出的是正确的回答。当这种情况发生时，亚历克斯就坚持自己的立场，并重复正确的回答。测试者终于回过神儿来，给亚历克斯以应得的犒赏。


    佩珀堡特别指出，这些实验促使亚历克斯和格里芬掌握了不仅与它们在野性状态下大不相同，而且可能更具难度的智力技能。从长期看，这可能是她的研究工作最有前景的方面。“我不想说它们是在学习英语，”她说，“因为我们无法进入一个动物的大脑，无法知道它说英语的感觉是否和我们一样。但它们却学会了一套自己完全不知道的交流方式。”她争论说，这项成就本身就意义深远——而且也不仅仅是因为它对关于动物智能的教条提出了挑战。她训练鹦鹉掌握它们自然本能以外的技能的方式——她将其称为“特别学习”——也为指导人类学习提供了一个有趣的范例。






    她的训练方法是互动的，利用“榜样/对手”的模式。这很简单：动物和人类在学习东西的时候，如果能够观察别人怎么做，甚至与之竞争，它（他）们就会更加积极地去学。如果学生去观察教练教别人如何学，而不是去听老师的长篇大论，就会产生最好的效果。看到老师给回答正确的人以奖赏，对回答错误的人以斥责，学生心领神会，受益菲浅。这个办法由迪特玛·托特70年代在德国的弗赖堡大学倡导，当佩珀堡将其用于亚历克斯时很快就起了作用。她在教当榜样的大学生时它能很快地跟上。亚历克斯开始与学生们争着引起佩珀堡的注意和得到她的赞许。这个“榜样/对手”的办法在亚历克斯身上运用如此成功，已被成功地用来帮助智力发育不良的孩子进行学习。





    到80年代后期，亚历克斯已经知道了50多个不同物体的名字，5种形状和7种颜色。它也知道了“相同”和“不同”的意思——这一步在人类智能的发展上如此重要，以至于它已成了“芝麻街”搞笑节目的一个日常性内容。把两个不同形状，颜色和材料的物体给亚历克斯看，然后问它，“有什么相同之处？”它就会回答，“没有！”因此它看起来不仅能辨别相同和不同的东西，甚至还知道更为抽象的概念——没有。亚历克斯已经相当熟练了，在佩珀堡的一个项目中，亚历克斯被提升为助教。“我们想看看亚历克斯是否能做格里芬的辅导教师，”佩珀堡解释说。“部分原因是，我们带来格里芬重复我们与亚历克斯的实验，以证明它不是某个鸟类中的爱因斯坦。” 

    为了演示，佩珀堡的一个大学生助手贾斯廷，指导格里芬和亚历克斯跳到高处工作架上去。就像在许多人的课堂上的情况一样，事情别别扭扭地开始了。格里芬看上去暴躁不安，不住地发牢骚，“想回去。”这天早上它大部分时间都在柜台面上将一把金属调羹推来推去，想回到实验室的柜台上去玩。贾斯廷拿出一个圆环问道，“格里芬，什么玩具？”格里芬答道，“木头！”而亚历克斯不予合作地叫道“石头！石头！石头！”接下去的几次试验中，格里芬正确地认出了软木，木头，和羊毛（这个词它的发音带着一声汽笛似的尖响：“呜――噜！”）。亚历克斯一声不响地坐在一旁。随着实验的进行，亚历克斯和格里芬似乎都渐渐进入事物本质，几乎是自然而然地进入了“榜样/对手”的模式。贾斯廷拿出一把钥匙问道，“什么玩具？”格里芬开始并没有回答，但当亚历克斯叫“钥匙！”时，格里芬马上照样说。当格里芬对一个玩具卡车不回应时，亚历克斯就以很不耐烦的声音插话说“卡车！卡车！”





    佩珀堡的指导方法大获成功，引起了人工智能研究者们的兴趣。最近她在麻省理工学院与计算机科学家合作，开发能够学习或能够帮助他人学习的软件。“模仿鹦鹉的学习比模仿人的学习要简单得多，”她说。但是她相信，可以写出计算机软件来回应——甚至“学习”——“榜样/对手”体系的正确回答和错误回答的相互影响。






    不管这种应用前景是对人还是对计算机，佩珀堡的研究正在促使心理学家们重新思考动物与人之间的界限。亚历克斯和格里芬的思维过程可能会与我们自己的有很多或有一点接近，佩珀堡说，但要否认它们的智力几乎是不可能的。


    最近一段在“榜样/对手”模式训练中偶然拍摄下来的录像证明了这一点：格里芬在试图说“纸”的时候，仓促间只“哎——呃”地叫了一声。亚历克斯明显地不耐烦到了极点，专横地命令格里芬“说清楚点！”

返回