De Waal Finds Primates Enforce Fairness, Upending Human Moral Dogma

Moral behavior in animals | Frans de Waal — TED

TED

Human morality is not a cultural veneer or religious invention, but an evolved bottom-up framework built on empathy and reciprocity shared across mammals.

AI-assisted summary of Moral behavior in animals | Frans de Waal — original source. Check the original for full context.

Source published: 2012-04-10

Key ideas

Human morality is fundamentally grounded in two evolutionary pillars shared with other mammals: reciprocity (fairness and justice) and empathy (compassion). (3:08)
Cooperation experiments demonstrate that chimpanzees and Asian elephants understand the necessity of partners to complete tasks and will voluntarily share work or act based on anticipated reciprocity. (3:39)
Token-choice experiments show chimpanzees systematically make pro-social decisions to feed group members alongside themselves, disproving the dogma that genuine concern for others is uniquely human. (11:00)
Capuchin monkey experiments reveal an innate aversion to inequity, as monkeys vehemently reject inferior food rewards like cucumber when a peer receives grapes for the same task. (12:31)

Detailed notes

## Background Published on YouTube by TED on April 10, 2012, this talk features primatologist Frans de Waal presenting research on the evolutionary roots of morality. According to the page description, de Waal shares behavioral experiments in primates and other mammals demonstrating that foundational moral traits like empathy, cooperation, fairness, and reciprocity are shared across species rather than being uniquely human.

## TL;DR Frans de Waal challenges the historical assumption that nature is strictly ruthless and selfish, arguing instead that human morality is an evolved biological trait built on two core pillars: reciprocity (fairness) and empathy (compassion). Through archival and contemporary laboratory experiments, he showcases coordinated cooperation and partner-awareness in chimpanzees and elephants, as well as contagious yawning, consoling gestures, and unselfish token-sharing. The presentation highlights his famous capuchin monkey study, in which individuals revolt against unequal pay when awarded cucumbers instead of grapes, demonstrating that an aversion to inequity exists outside human culture. Ultimately, de Waal concludes that morality develops from the bottom up through deep evolutionary continuity rather than solely from top-down human institutions or divine mandate.

## Atmosphere & style The talk combines academic rigor with an easygoing, wry wit that consistently delights the live audience, eliciting loud bursts of laughter during video clips of clever elephant freeloading and furious monkey food-flinging. De Waal delivers his arguments with warm, understated authority, moving seamlessly from 15th-century art history into behavioral primatology while gently puncturing rigid philosophical dogmas. The presentation has the feel of an illuminating and accessible masterclass that transforms profound, long-debated ethical questions into immediate, tangible, and emotionally relatable moments of animal life.

## Bulletin - [03:08](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=188s) Human morality is fundamentally grounded in two evolutionary pillars shared with other mammals: reciprocity (fairness and justice) and empathy (compassion). - [03:39](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=219s) Cooperation experiments demonstrate that chimpanzees and Asian elephants understand the necessity of partners to complete tasks and will voluntarily share work or act based on anticipated reciprocity. - [11:00](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=660s) Token-choice experiments show chimpanzees systematically make pro-social decisions to feed group members alongside themselves, disproving the dogma that genuine concern for others is uniquely human. - [12:31](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=751s) Capuchin monkey experiments reveal an innate aversion to inequity, as monkeys vehemently reject inferior food rewards like cucumber when a peer receives grapes for the same task.

## Key takeaways - [00:15](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=15s) Hieronymus Bosch's 'The Garden of Earthly Delights' raises the foundational question of what morality would look like without religious influence or divine mandate. - [01:45](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=105s) The discovery of post-conflict reconciliation in chimpanzees and bonobos overturned the long-held dogma that animal behavior is governed entirely by selfish aggression and competition. - [02:45](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=165s) The proverb 'homo homini lupus' ('man is a wolf to man') is inaccurate to both wolves, which are intensely cooperative, and humans, who are deeply empathetic. - [03:08](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=188s) All moral systems depend on two indispensable pillars: reciprocity (associated with justice) and empathy (associated with compassion). - [04:15](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=255s) Chimpanzees will expend effort to haul food platforms to assist hungry partners even when already satiated, anticipating future reciprocity. - [05:39](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=339s) Asian elephants intuitively understand joint-action mechanics with continuous ropes, with some spontaneously anchoring the rope with a foot to freeload while a partner pulls. - [08:03](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=483s) Empathy operates across two evolutionary levels: the somatic body channel (emotional contagion) and the cognitive channel (perspective-taking). - [08:55](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=535s) Contagious yawning across humans and chimpanzees provides biological evidence of involuntary emotional synchronization rooted in mirror networks. - [09:40](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=580s) Apes exhibit consolation behaviors toward defeated rivals that mirror the comforting actions observed in human toddlers reacting to distressed family members. - [11:00](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=660s) Token experiments demonstrate that chimpanzees deliberately prefer pro-social choices over selfish ones, particularly when interacting with well-behaved group members. - [12:31](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=751s) Capuchin monkeys display acute inequity aversion, violently refusing cucumber rewards and flinging them at researchers when observing peers receiving grapes. - [15:09](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=909s) Follow-up studies with chimpanzees revealed privileged individuals refusing grapes until disadvantaged partners received equal treatment, satisfying strict philosophical definitions of fairness. - [15:30](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=930s) Human morality is not a top-down cultural invention or religious dictate, but a bottom-up evolutionary adaptation built from traits shared widely across social mammals.

## Detailed walkthrough ### [00:15](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=15s) Origins, Hieronymus Bosch, and the Discovery of Reconciliation

Frans de Waal opens his talk by tracing his intellectual roots back to his birthplace of 's-Hertogenbosch (Den Bosch), the Dutch town from which the 15th-century painter Hieronymus Bosch took his name. De Waal shares his longstanding fascination with the painter, who lived during an era when the authority of religion was beginning to wane. Pondering Bosch's mindset, de Waal suggests the artist was exploring what might happen to human society if religion lost its sway. This curiosity yielded Bosch's masterwork, *The Garden of Earthly Delights*, which many art historians interpret as depicting humanity before the biblical Fall, or perhaps a vision of humanity without any Fall at all. For de Waal, the triptych raises a fundamental question: what sort of morality would we possess if humanity had never tasted the fruit of knowledge?

Years later, as a student, de Waal traded the artistic garden of Bosch for a zoological garden in Arnhem, home to a colony of chimpanzees. There, he took early photographs with infant chimps and observed power struggles that would become the subject of his first major book, *Chimpanzee Politics*. At the time, animal behavior research was thoroughly dominated by models of aggression, dominance, and unyielding competition. Science painted a bleak portrait of the natural world—one that extended directly into views of human nature—suggesting that deep down, living creatures are aggressive competitors relentlessly pursuing selfish gain. De Waal humorously shows a slide of his book launch, joking that while he was not sure how well the chimpanzees could actually read it, they certainly appeared engrossed by the pages.

While immersed in studies of power and aggression, de Waal made an observation that shattered the conventional paradigm: chimpanzees routinely reconcile after conflicts. He illustrates this with an image of two male chimps who had fought violently and fled into a tree canopy. One male reached his hand out toward his rival; within a second, both met in the fork of the tree, embracing and kissing. In a scientific landscape where only winning or losing mattered, peacemaking appeared nonsensical. Yet de Waal observed the same drive in bonobos, who notoriously navigate tension through sexual contact rather than fighting. In both species, the underlying principle is identical: conflict threatens a valuable relationship, compelling the animals to repair the bond.

This insight overturned the entrenched belief—found throughout political science, economics, philosophy, and the humanities—summarized by the Latin proverb *homo homini lupus* ("man is a wolf to man"). De Waal rejects this depiction as deeply misguided on both counts: “I think it's a very unfair image for the wolf,” de Waal argues, noting that wolves are intensely cooperative animals, which explains why humans share their homes with domestic dogs. Furthermore, “it's really unfair to humanity, because humanity is actually much more cooperative and empathic than given credit for.”

```mermaid flowchart TD accTitle: The Shift in Evolutionary Perspectives on Animal Behavior accDescr: Diagram illustrating the shift from a competition-only view of nature to a model incorporating social reconciliation and morality.

subgraph OldView["Traditional Competitiveness View"] A["Dominance & Aggression"] --> B["Conflict / Fight"] B --> C["Win or Lose Outcome"] end

subgraph NewView["Valued Relationship Model"] D["Social Bonds & Cooperation"] --> E["Conflict Occurs"] E --> F["Reconciliation (Kiss, Embrace, Sex)"] F --> G["Relationship Repaired"] end

OldView -.->|"Challenged by Reconciliation Data"| NewView ```

- Hieronymus Bosch worked in 15th-century Den Bosch, painting *The Garden of Earthly Delights* amid waning religious authority. - Early behavioral research in Arnhem focused on chimpanzee power dynamics, dominance hierarchies, and aggression. - Post-conflict reconciliation was documented in chimpanzees via grooming, hand-reaching, embraces, and kisses, and in bonobos through socio-sexual behavior.

---

[03:08](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=188s) The Two Pillars of Morality and Cooperation in Chimpanzees

De Waal identifies two foundational pillars that underpin any human moral system: reciprocity (inextricably tied to a sense of justice and fairness) and empathy (tied to compassion). While human moral philosophy incorporates additional complexities, de Waal maintains that stripped of these two core supports, human morality would largely collapse. To investigate whether these building blocks exist beyond our species, researchers look to cooperation experiments across different taxa.

```mermaid flowchart LR accTitle: The Two Pillars of Morality accDescr: Diagram showing the two foundational pillars of morality identified by Frans de Waal.

Morality["Foundations of Morality"] Pillar1["Reciprocity & Fairness\n(Justice, Favor-Trading)"] Pillar2["Empathy & Compassion\n(Emotional & Cognitive Channels)"]

Morality --> Pillar1 Morality --> Pillar2 ```

De Waal displays archival black-and-white film from the Yerkes Primate Center, showing experiments conducted nearly a century ago on chimpanzee cooperative problem-solving. In the footage, two juvenile chimps are presented with an apparatus featuring a heavily weighted box loaded with food. Because the box is too cumbersome for a single animal to haul in alone, the apes must coordinate their actions. The video demonstrates remarkable synchronization as the two pull the ropes in unison to bring the food within reach.

The test is then made significantly more complex: researchers feed one chimp beforehand, eliminating its hunger and intrinsic motivation to pull. Despite having zero interest in the food on the box, the satiated partner responds to the gestures and solicitations of the hungry chimp, stepping up to help haul the apparatus across the floor. Once the box arrives, the hungry partner consumes virtually the entire reward. De Waal points out two crucial cognitive elements in this exchange: first, the hungry chimp clearly grasps the necessity of a partner to achieve the goal; second, the partner voluntarily expends effort without an immediate payoff. De Waal attributes this willingness to long-term reciprocity, noting: “He will get a return favor at some point in the future.”

---

[05:39](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=339s) Elephant Cooperation and Intelligent Freeloading

To determine whether cooperative problem-solving extends beyond primates, de Waal’s collaborator Josh Plotnik adapted the joint-pulling paradigm for Asian elephants in Thailand. Working with elephants presents severe experimental challenges: safety concerns are paramount, and building an apparatus too heavy for an animal that weighs several tons would require an absurdly unwieldy contraption. The team resolved this by threading a single continuous rope through a platform holding food bowls. If one elephant pulls its end prematurely, the rope slips through the apparatus and spools away, leaving both animals empty-handed. Success requires simultaneous coordination.

When released together, the elephant pair easily synchronizes their movements, walking forward in lockstep, grasping their respective rope ends with their trunks, and reeling the food platform toward them. To test whether the elephants genuinely understood the cooperative mechanics—rather than merely reacting to the presence of food—the researchers altered the conditions by staggering the release, letting one elephant enter the testing enclosure before the second.

The single elephant understood immediately that pulling alone would ruin the trial. Instead of tugging prematurely, the elephant innovated an unscripted shortcut: it calmly stepped onto the rope with its massive foot, anchoring it securely, and waited for its partner to amble over. Once the partner arrived and began pulling, the first elephant simply let the other do all the heavy physical lifting while keeping its foot planted, casually grabbing its share of the food when the tray arrived. The audience reacts with laughter as de Waal highlights this clever act of freeloading, emphasizing that such unprompted, illicit solutions demonstrate high-level physical and social cognition that researchers had never explicitly trained.

- The elephant cooperation studies were led by Josh Plotnik in Thailand using a continuous single-rope apparatus. - Premature pulling results in the unthreaded rope unraveling entirely, forcing the elephants to comprehend the necessity of joint action. - Individual elephants independently discovered freeloading tactics, anchoring the rope with a foot to allow the late-arriving partner to do all the mechanical pulling.

---

[08:03](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=483s) The Two Channels of Empathy: Contagion and Consolation

Turning to empathy—his primary research focus—de Waal defines it standardly as the capacity to understand and share the emotional state of another individual. He divides empathy into two operational pathways: 1. **The Body Channel (Emotional Contagion):** An ancient, somatic pathway where observing another’s emotional posture triggers mimicry. When interacting with someone who is visibly sorrowful, observers adopt subdued facial expressions and postures, swiftly experiencing feelings of sadness themselves. This bodily synchronization is widespread across mammals—which explains why humans keep dogs and cats as companions rather than emotionally detached reptiles like turtles or snakes. 2. **The Cognitive Channel (Perspective-Taking):** A higher-order ability to adopt the subjective viewpoint of another individual. This trait is much rarer in the animal kingdom, documented primarily in large-brained mammals like apes and elephants.

Synchronization is an evolutionary foundation of empathy, easily demonstrated in humans through contagious yawning. When humans witness someone yawning, their brains activate mirror networks associated with empathy. Individuals exhibiting strong yawn contagion test higher on empathy scales, whereas populations with empathy deficits, such as autistic children, show no susceptibility to contagious yawning. To test this in primates, de Waal’s team exposed chimpanzees to an animated chimpanzee head programmed to yawn on a computer screen. The chimps regularly yawned in response, proving that involuntary bodily synchronization is shared deeply across the mammalian lineage.

Moving from low-level contagion to targeted empathy, de Waal describes consolation behavior. He shows a photograph of an adult male chimp that has just lost an aggressive brawl; screaming in agitation, the defeated ape is approached by an uninvolved juvenile chimp, who puts an arm around his shoulder to calm him down. This gesture directly parallels human consolation. De Waal points out that developmental psychologists study empathy in toddlers in an identical manner, instructing a family member to feign distress to measure whether the child approaches with comforting gestures. In both apes and humans, reassurance is an empathy-driven response designed to alleviate another's stress.

---

[10:25](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=625s) Testing Altruism: Caring About the Welfare of Others

De Waal addresses a long-held dogma in the behavioral sciences: the assertion that genuine altruism and concern for the well-being of unrelated others are uniquely human capabilities. For decades, the dominant academic consensus held that non-human animals are fundamentally indifferent to the welfare of their peers, motivated solely by direct, immediate self-interest.

To challenge this assumption, de Waal and his colleagues designed a simple token-choice experiment conducted at the Yerkes National Primate Research Center field station in Lawrenceville, Georgia. The chimpanzees live in rich social groups in spacious outdoor enclosures and are periodically invited indoors to participate in voluntary cognitive tests. In this setup, two chimpanzees are placed side-by-side in adjacent testing compartments separated by a transparent partition, allowing them full visual contact. One chimpanzee is presented with a bucket filled with colored tokens, where each token represents a distinct social and nutritional outcome for the chooser and its partner.

[11:00](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=660s) Pro-Social Choices in Chimpanzees

Frans de Waal describes an experiment conducted alongside Vicki Horner to investigate whether chimpanzees display unselfish, pro-social tendencies. The chimpanzee making the decision is presented with a bucket containing two differently colored tokens. One token represents a selfish choice: when handed to the experimenters, food rewards are placed on a table, but only the chooser receives food while the partner receives nothing. In a video demonstrating this, the observer chimp immediately walks away upon seeing the selfish red token chosen, knowing well that the trial yields no reward for her. The other token is pro-social: when handed over, both chimpanzees receive food. Crucially, the choosing chimpanzee receives a food reward regardless of which token she selects, meaning that purely self-interested calculation would predict random, 50-50 selection between the two colors.

Instead of choosing blindly, the chimpanzees demonstrate a clear preference for the pro-social token, systematically opting to feed their partner alongside themselves. This pro-social behavior increases when the partner chimpanzee draws gentle attention to herself. However, if the partner becomes pushy or attempts intimidation—such as spitting water into the enclosure—the chooser's willingness to select the pro-social option drops sharply. De Waal jokes that the chimp's attitude shifts to: “If you're not behaving, I'm not going to be pro-social today.” When tested in an empty setup with no partner present, their preference for the sharing token drops back to baseline. De Waal emphasizes: “So we found that the chimpanzees do care about the well-being of somebody else -- especially, these are other members of their own group.”

- **Setup**: One bucket with two colors of tokens; choosing chimp always receives food, but only the pro-social token delivers food to the partner as well. - **Baseline**: At random, choices should sit on the 50 percent line, but chimps reliably choose the pro-social option above chance. - **Social dynamics**: Mild reminders and attention from the partner elevate sharing, whereas overt intimidation or spitting reduces pro-social choices.

---

[12:31](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=751s) The Inequity Experiment: Cucumbers and Grapes

De Waal turns to his famous fairness study, originally conducted roughly a decade earlier with Sarah Brosnan using capuchin monkeys and subsequently replicated in dogs, birds, and chimpanzees. Pairs of capuchin monkeys who live together in a social group are placed side-by-side in adjacent testing chambers. Their task is straightforward: pick up a small rock and hand it to the experimenter. When both monkeys receive a slice of cucumber as a reward, they are perfectly content to repeat the task 25 times in a row. Though De Waal remarks that cucumber is essentially “only really water in my opinion,” the monkeys happily accept it under equal conditions.

Inequity is introduced when the researchers vary the reward quality. As De Waal quips, “the food preferences of my capuchin monkeys correspond exactly with the prices in the supermarket,” making grapes vastly superior to cucumber. Demonstrating video footage with naive monkeys who had never performed the task before—heightening their emotional reactions—the monkey on the left hands over a rock and receives cucumber, which she readily consumes. But when she watches her neighbor on the right receive and eat a grape for performing the identical rock exchange, the dynamic shatters. When handed another rock, the left monkey hands it over, receives another piece of cucumber, and promptly flings the cucumber back at the researcher in disgust. She repeatedly rattles the enclosure, tests a rock against the clear wall, and hands it over again, only to violently reject the second cucumber slice. The audience erupts in laughter and applause as De Waal remarks: “So this is basically the Wall Street protest that you see here.”

```mermaid flowchart TD accTitle: Capuchin Monkey Inequity Experiment accDescr: Flowchart showing the unequal rewards given to two monkeys performing the same task and the resulting rejection. subgraph EqualRewards["Equal Condition"] E1["Monkey A trades rock"] --> R1["Receives cucumber"] E2["Monkey B trades rock"] --> R2["Receives cucumber"] R1 & R2 --> OK["Both happily repeat task up to 25 times"] end subgraph UnequalRewards["Inequity Condition"] U1["Monkey A trades rock"] --> R3["Receives cucumber"] U2["Monkey B trades rock"] --> R4["Receives grape"] R3 & R4 --> REJ["Monkey A rejects cucumber and throws it at experimenter"] end ```

---

[15:09](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=909s) Academic Skepticism and the Evolution of Morality

The fairness study attracted substantial pushback from human-centric disciplines. De Waal recounts that anthropologists, economists, and philosophers resisted the findings because they had long assumed that a concept as intricate as fairness belonged strictly to the human domain. One philosopher went so far as to write that monkeys could not possibly possess a sense of fairness because fairness had been invented during the French Revolution. Another scholar published a full chapter asserting he would only accept the findings as evidence of fairness if the privileged individual receiving grapes voluntarily refused them until the disadvantaged partner received one too. De Waal notes that Sarah Brosnan later ran the experiment with chimpanzees and found pairs where the recipient of the grape did precisely that, refusing to eat until the other chimp also received a grape. To this, De Waal wryly adds: “And I think philosophers need to rethink their philosophy for a while.”

Concluding the talk, De Waal argues that human morality is not an artificial cultural veneer imposed from above, but rather the product of deep evolutionary continuity. While full human morality encompasses complexities beyond the scope of his talk, it rests entirely on evolutionary building blocks present across other social animals: empathy, consolation, pro-social sharing, reciprocity, and an aversion to unfairness. Summarizing his thesis, De Waal declares: “I believe there's an evolved morality.” By investigating these elemental behaviors in non-human primates, science can construct a bottom-up framework for moral behavior that does not depend on divine mandate or organized religion.

## Notable quotes > [00:15](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=15s) humanity is actually much more cooperative and empathic than given credit for. — Frans de Waal

> [15:09](https://www.youtube.com/watch?v=GcJxRqTs5nk&t=909s) I believe there's an evolved morality. — Frans de Waal

## Mentioned Frans de Waal, Hieronymus Bosch, The Garden of Earthly Delights, Chimpanzee Politics, Yerkes National Primate Research Center, Josh Plotnik, Vicki Horner, Sarah Brosnan

## Video description http://www.ted.com Empathy, cooperation, fairness and reciprocity -- caring about the well-being of others seems like a very human trait. But Frans de Waal shares some surprising videos of behavioral tests, on primates and other mammals, that show how many of these moral traits all of us share.

TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes. Featured speakers have included Al Gore on climate change, Philippe Starck on design, Jill Bolte Taylor on observing her own stroke, Nicholas Negroponte on One Laptop per Child, Jane Goodall on chimpanzees, Bill Gates on malaria and mosquitoes, Pattie Maes on the "Sixth Sense" wearable tech, and "Lost" producer JJ Abrams on the allure of mystery. TED stands for Technology, Entertainment, Design, and TEDTalks cover these topics as well as science, business, development and the arts. Closed captions and translated subtitles in a variety of languages are now available on TED.com, at http://www.ted.com/translate

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[Source](https://www.youtube.com/watch?v=GcJxRqTs5nk)

中文简报

德瓦尔发现灵长类动物会维护公平，颠覆人类道德教条人类道德并非文化外衣或宗教发明，而是建立在哺乳动物共有的共情与互惠基础之上、自下而上演化出的框架。弗朗斯·德瓦尔（Frans de Waal）对自然纯粹无情且自私的历史假设提出质疑，认为人类道德是一种演化而来的生物学特征，建立在两大核心支柱之上：互惠（公平）与共情（同情心）。通过历史档案记录和当代实验室实验，他展示了黑猩猩和大象的协调合作及伴侣意识，以及传染性打哈欠、安慰举动和无私的代币分享行为。演讲重点介绍了著名的卷尾猴实验，该实验中个体在完成同样任务却得到黄瓜而非葡萄时，会强烈抗议这种不平等报酬，表明对不公的厌恶存在于人类文化之外。德瓦尔最终得出结论，道德是通过深厚的演化连续性自下而上发展而来的，而非完全源自自上而下的人类制度或神的旨意。人类道德从根本上建立在与其他哺乳动物共有的两大演化支柱之上：互惠（公平与正义）以及共情（同情心）。 (3:08) 合作实验表明，黑猩猩和亚洲象明白需要伙伴才能完成任务，并且会自愿分担工作或基于预期的互惠采取行动。 (3:39) 代币选择实验显示，黑猩猩会系统性地做出亲社会决策，在喂饱自己的同时也让群体成员获得食物，这反驳了认为唯有人类才会真正关心他人的教条。 (11:00) 卷尾猴实验揭示了对不公的先天厌恶：当同伴完成相同任务获得葡萄时，卷尾猴会极力拒绝黄瓜等较劣质的食物报酬。 (12:31)

Source quotes

[0:15] Frans de Waal: humanity is actually much more cooperative and empathic than given credit for. [15:09] Frans de Waal: I believe there's an evolved morality.

Original transcript

[0:15] I was born in Den Bosch, [0:17] where the painter Hieronymus Bosch named himself after. [0:20] And I've always been very fond of this painter [0:23] who lived and worked in the 15th century. [0:25] And what is interesting about him in relation to morality [0:28] is that he lived at a time where religion's influence was waning, [0:31] and he was sort of wondering, I think, [0:33] what would happen with society if there was no religion [0:36] or if there was less religion. [0:37] And so he painted this famous painting, "The Garden of Earthly Delights," [0:41] which some have interpreted as being humanity before the Fall, [0:44] or being humanity without any Fall at all. [0:48] And so it makes you wonder, [0:49] what would happen if we hadn't tasted the fruit of knowledge, so to speak, [0:53] and what kind of morality would we have. [0:56] Much later, as a student, I went to a very different garden, [0:59] a zoological garden in Arnhem where we keep chimpanzees. [1:04] This is me at an early age with a baby chimpanzee. [1:07] (Laughter) [1:10] And I discovered there [1:11] that the chimpanzees are very power-hungry and wrote a book about it. [1:15] And at that time the focus in a lot of animal research [1:17] was on aggression and competition. [1:20] I painted a whole picture of the animal kingdom [1:22] and humanity included, was that deep down we are competitors, we are aggressive, [1:27] we are all out for our own profit, basically. [1:30] This is the launch of my book. [1:32] I'm not sure how well the chimpanzees read it, [1:35] but they surely seemed interested in the book. [1:37] (Laughter) [1:39] Now in the process of doing all this work [1:42] on power and dominance and aggression and so on, [1:45] I discovered that chimpanzees reconcile after fights. [1:49] And so what you see here is two males who have had a fight. [1:51] They ended up in a tree, and one of them holds out a hand to the other. [1:55] And about a second after I took the picture, [1:57] they came together in the fork of the tree [1:59] and kissed and embraced each other. [2:01] And this is very interesting [2:02] because at the time, everything was about competition and aggression, [2:05] so it wouldn't make any sense. [2:07] The only thing that matters is that you win or you lose. [2:10] But why reconcile after a fight? That doesn't make any sense. [2:12] This is the way bonobos do it. Bonobos do everything with sex. [2:15] And so they also reconcile with sex. [2:17] But the principle is exactly the same. [2:19] The principle is that you have a valuable relationship [2:23] that is damaged by conflict, so you need to do something about it. [2:27] So my whole picture of the animal kingdom, and including humans also, [2:32] started to change at that time. [2:34] So we have this image in political science, economics, the humanities, [2:38] the philosophy for that matter, that man is a wolf to man. [2:42] And so deep down, our nature is actually nasty. [2:45] I think it's a very unfair image for the wolf. [2:48] The wolf is, after all, a very cooperative animal. [2:51] And that's why many of you have a dog at home, [2:53] which has all these characteristics also. [2:56] And it's really unfair to humanity, [2:57] because humanity is actually much more cooperative and empathic [3:01] than given credit for. [3:03] So I started getting interested in those issues [3:05] and studying that in other animals. [3:08] So these are the pillars of morality. [3:09] If you ask anyone, "What is morality based on?" [3:13] these are the two factors that always come out. [3:15] One is reciprocity, [3:17] and associated with it is a sense of justice and a sense of fairness. [3:21] And the other one is empathy and compassion. [3:23] And human morality is more than this, but if you would remove these two pillars, [3:27] there would be not much remaining, I think. [3:29] So they're absolutely essential. [3:31] So let me give you a few examples here. [3:33] This is a very old video from the Yerkes Primate Center, [3:36] where they trained chimpanzees to cooperate. [3:39] So this is already about a hundred years ago [3:41] that we were doing experiments on cooperation. [3:44] What you have here is two young chimpanzees who have a box, [3:48] and the box is too heavy for one chimp to pull in. [3:51] And of course, there's food on the box. [3:53] Otherwise they wouldn't be pulling so hard. [3:55] And so they're bringing in the box. [3:57] And you can see that they're synchronized. [3:59] You can see that they work together, they pull at the same moment. [4:02] It's already a big advance over many other animals [4:05] who wouldn't be able to do that. [4:06] Now you're going to get a more interesting picture, [4:09] because now one of the two chimps has been fed. [4:11] So one of the two is not really interested in the task anymore. [4:17] (Laughter) [4:24] (Laughter) [4:35] (Laughter) [4:38] [- and sometimes appears to convey its wishes and meanings by gestures.] [4:51] Now look at what happens at the very end of this. [4:56] (Laughter) [5:07] He takes basically everything. [5:09] (Laughter) [5:12] There are two interesting parts about this. [5:14] One is that the chimp on the right [5:16] has a full understanding he needs the partner -- [5:18] so a full understanding of the need for cooperation. [5:21] The second one is that the partner is willing to work [5:23] even though he's not interested in the food. [5:25] Why would that be? [5:27] Well, that probably has to do with reciprocity. [5:29] There's actually a lot of evidence in primates and other animals [5:32] that they return favors. [5:33] He will get a return favor at some point in the future. [5:36] And so that's how this all operates. [5:39] We do the same task with elephants. [5:41] Now, it's very dangerous to work with elephants. [5:44] Another problem with elephants is that you cannot make an apparatus [5:47] that is too heavy for a single elephant. [5:49] Now you can probably make it, [5:51] but it's going to be a pretty clumsy apparatus, I think. [5:54] And so what we did in that case -- [5:55] we do these studies in Thailand for Josh Plotnik -- [5:58] is we have an apparatus around which there is a rope, a single rope. [6:02] And if you pull on this side of the rope, the rope disappears on the other side. [6:06] So two elephants need to pick it up at exactly the same time, and pull. [6:09] Otherwise nothing is going to happen and the rope disappears. [6:12] The first tape you're going to see [6:14] is two elephants who are released together arrive at the apparatus. [6:18] The apparatus is on the left, with food on it. [6:22] And so they come together, they arrive together, [6:25] they pick it up together, and they pull together. [6:27] So it's actually fairly simple for them. [6:31] There they are. [6:40] So that's how they bring it in. [6:42] But now we're going to make it more difficult. [6:44] Because the purpose of this experiment [6:46] is to see how well they understand cooperation. [6:48] Do they understand that as well as the chimps, for example? [6:51] What we do in the next step is we release one elephant before the other [6:54] and that elephant needs to be smart enough [6:56] to stay there and wait and not pull at the rope -- [6:59] because if he pulls at the rope, it disappears and the whole test is over. [7:02] Now this elephant does something illegal that we did not teach it. [7:05] But it shows the understanding he has, [7:08] because he puts his big foot on the rope, [7:10] stands on the rope and waits there for the other, [7:13] and then the other is going to do all the work for him. [7:15] So it's what we call freeloading. [7:18] (Laughter) [7:21] But it shows the intelligence that the elephants have. [7:24] They developed several of these alternative techniques [7:26] that we did not approve of, necessarily. [7:28] (Laughter) [7:29] So the other elephant is now coming ... [7:35] and is going to pull it in. [7:54] Now look at the other; it doesn't forget to eat, of course. [7:57] (Laughter) [8:00] This was the cooperation and reciprocity part. [8:03] Now something on empathy. [8:04] Empathy is my main topic at the moment, of research. [8:06] And empathy has two qualities: [8:08] One is the understanding part of it. [8:10] This is just a regular definition: [8:12] the ability to understand and share the feelings of another. [8:14] And the emotional part. [8:16] Empathy has basically two channels: One is the body channel, [8:19] If you talk with a sad person, [8:21] you're going to adopt a sad expression and a sad posture, [8:24] and before you know it, you feel sad. [8:26] And that's sort of the body channel of emotional empathy, [8:30] which many animals have. [8:32] Your average dog has that also. [8:33] That's why people keep mammals in the home [8:35] and not turtles or snakes or something like that, [8:38] who don't have that kind of empathy. [8:39] And then there's a cognitive channel, [8:41] which is more that you can take the perspective of somebody else. [8:44] And that's more limited. [8:45] Very few animals, I think elephants and apes, can do that kind of thing. [8:51] So synchronization, [8:53] which is part of that whole empathy mechanism, [8:55] is a very old one in the animal kingdom. [8:57] In humans, of course, we can study that with yawn contagion. [9:00] Humans yawn when others yawn. [9:02] And it's related to empathy. [9:04] It activates the same areas in the brain. [9:06] Also, we know that people who have a lot of yawn contagion [9:09] are highly empathic. [9:10] People who have problems with empathy, such as autistic children, [9:13] they don't have yawn contagion. [9:15] So it is connected. [9:16] And we study that in our chimpanzees by presenting them with an animated head. [9:20] So that's what you see on the upper-left, an animated head that yawns. [9:24] And there's a chimpanzee watching, [9:25] an actual real chimpanzee watching a computer screen [9:28] on which we play these animations. [9:36] (Laughter) [9:38] So yawn contagion that you're probably all familiar with -- [9:41] and maybe you're going to start yawning soon now -- [9:44] is something that we share with other animals. [9:47] And that's related to that whole body channel of synchronization [9:50] that underlies empathy, [9:52] and that is universal in the mammals, basically. [9:55] We also study more complex expressions -- This is consolation. [9:58] This is a male chimpanzee who has lost a fight and he's screaming, [10:01] and a juvenile comes over and puts an arm around him [10:04] and calms him down. [10:05] That's consolation. [10:06] It's very similar to human consolation. [10:08] And consolation behavior -- [10:10] (Laughter) [10:12] it's empathy driven. [10:13] Actually, the way to study empathy in human children [10:16] is to instruct a family member to act distressed, [10:19] and then to see what young children do. [10:21] And so it is related to empathy, [10:23] and that's the kind of expressions we look at. [10:25] We also recently published an experiment you may have heard about. [10:28] It's on altruism and chimpanzees, [10:30] where the question is: Do chimpanzees care about the welfare of somebody else? [10:35] And for decades it had been assumed that only humans can do that, [10:39] that only humans worry about the welfare of somebody else. [10:42] Now we did a very simple experiment. [10:45] We do that on chimpanzees that live in Lawrenceville, [10:48] in the field station of Yerkes. [10:49] And so that's how they live. [10:51] And we call them into a room and do experiments with them. [10:54] In this case, we put two chimpanzees side-by-side, [10:56] and one has a bucket full of tokens, and the tokens have different meanings. [11:00] One kind of token feeds only the partner who chooses, [11:02] the other one feeds both of them. [11:04] So this is a study we did with Vicki Horner. [11:08] And here, you have the two color tokens. [11:11] So they have a whole bucket full of them. [11:13] And they have to pick one of the two colors. [11:16] You will see how that goes. [11:19] So if this chimp makes the selfish choice, [11:22] which is the red token in this case, [11:25] he needs to give it to us, [11:26] we pick it up, we put it on a table where there's two food rewards, [11:30] but in this case, only the one on the right gets food. [11:32] The one on the left walks away because she knows already [11:35] that this is not a good test for her. [11:37] Then the next one is the pro-social token. [11:40] So the one who makes the choices -- that's the interesting part here -- [11:43] for the one who makes the choices, it doesn't really matter. [11:46] So she gives us now a pro-social token and both chimps get fed. [11:49] So the one who makes the choices always gets a reward. [11:52] So it doesn't matter whatsoever. [11:53] And she should actually be choosing blindly. [11:57] But what we find is that they prefer the pro-social token. [12:00] So this is the 50 percent line, that's the random expectation. [12:03] And especially if the partner draws attention to itself, they choose more. [12:07] And if the partner puts pressure on them -- [12:09] so if the partner starts spitting water and intimidating them -- [12:12] then the choices go down. [12:14] (Laughter) [12:15] It's as if they're saying, [12:17] "If you're not behaving, I'm not going to be pro-social today." [12:20] And this is what happens without a partner, [12:22] when there's no partner sitting there. [12:24] So we found that the chimpanzees do care about the well-being of somebody else -- [12:27] especially, these are other members of their own group. [12:31] So the final experiment that I want to mention to you [12:34] is our fairness study. [12:35] And so this became a very famous study. [12:38] And there are now many more, [12:40] because after we did this about 10 years ago, [12:42] it became very well-known. [12:44] And we did that originally with capuchin monkeys. [12:47] And I'm going to show you the first experiment that we did. [12:49] It has now been done with dogs and with birds [12:52] and with chimpanzees. [12:54] But with Sarah Brosnan, we started out with capuchin monkeys. [12:59] So what we did is we put two capuchin monkeys side-by-side. [13:02] Again, these animals, live in a group, they know each other. [13:05] We take them out of the group, put them in a test chamber. [13:09] And there's a very simple task that they need to do. [13:11] And if you give both of them cucumber for the task, [13:15] the two monkeys side-by-side, [13:16] they're perfectly willing to do this 25 times in a row. [13:19] So cucumber, even though it's only really water in my opinion, [13:22] but cucumber is perfectly fine for them. [13:26] Now if you give the partner grapes -- [13:28] the food preferences of my capuchin monkeys [13:30] correspond exactly with the prices in the supermarket -- [13:33] and so if you give them grapes -- it's a far better food -- [13:37] then you create inequity between them. [13:39] So that's the experiment we did. [13:41] Recently, we videotaped it with new monkeys [13:43] who'd never done the task, [13:45] thinking that maybe they would have a stronger reaction, [13:47] and that turned out to be right. [13:49] The one on the left is the monkey who gets cucumber. [13:52] The one on the right is the one who gets grapes. [13:54] The one who gets cucumber -- [13:55] note that the first piece of cucumber is perfectly fine. [13:58] The first piece she eats. [14:00] Then she sees the other one getting grape, and you will see what happens. [14:04] So she gives a rock to us. That's the task. [14:07] And we give her a piece of cucumber and she eats it. [14:10] The other one needs to give a rock to us. [14:13] And that's what she does. [14:15] And she gets a grape ... [14:18] and eats it. [14:20] The other one sees that. [14:21] She gives a rock to us now, [14:22] gets, again, cucumber. [14:27] (Laughter) [14:41] (Laughter ends) [14:43] She tests a rock now against the wall. [14:46] She needs to give it to us. [14:48] And she gets cucumber again. [14:52] (Laughter) [14:59] So this is basically the Wall Street protest that you see here. [15:02] (Laughter) [15:05] (Applause) [15:09] I still have two minutes left -- [15:11] let me tell you a funny story about this. [15:13] This study became very famous and we got a lot of comments, [15:17] especially anthropologists, economists, philosophers. [15:20] They didn't like this at all. [15:22] Because they had decided in their minds, I believe, [15:24] that fairness is a very complex issue, and that animals cannot have it. [15:29] And so one philosopher even wrote us [15:31] that it was impossible that monkeys had a sense of fairness [15:34] because fairness was invented during the French Revolution. [15:37] (Laughter) [15:40] And another one wrote a whole chapter [15:42] saying that he would believe it had something to do with fairness, [15:46] if the one who got grapes would refuse the grapes. [15:48] Now the funny thing is that Sarah Brosnan, who's been doing this with chimpanzees, [15:52] had a couple of combinations of chimpanzees [15:54] where, indeed, the one who would get the grape [15:57] would refuse the grape until the other guy also got a grape. [16:00] So we're getting very close to the human sense of fairness. [16:02] And I think philosophers need to rethink their philosophy for a while. [16:06] So let me summarize. [16:08] I believe there's an evolved morality. [16:10] I think morality is much more than what I've been talking about, [16:13] but it would be impossible without these ingredients [16:16] that we find in other primates, [16:17] which are empathy and consolation, [16:19] pro-social tendencies and reciprocity and a sense of fairness. [16:23] And so we work on these particular issues [16:25] to see if we can create a morality from the bottom up, so to speak, [16:28] without necessarily god and religion involved, [16:31] and to see how we can get to an evolved morality. [16:34] And I thank you for your attention. [16:36] (Applause)