Frans de Waal, one of the world’s preeminent primatologists, passed away on 14 March 2024, at the age of 75. He was the Charles Howard Candler Professor Emeritus of Psychology and former director of the Living Links Center for the Advanced Study of Ape and Human Evolution at the Emory National Primate Research Center.
His passing is a loss not just for his family and friends, but for science and society more broadly. De Waal’s death ends a career that showed what science can accomplish at its very best, by changing our perspective on ourselves and our place in the cosmos.
Frans was more than just a colleague and friend to me. He was a teacher. I count myself among the innumerable people who were impacted by his writing and lecturing in clear and explicit ways.
That is why I don’t feel that it is inappropriate for me to pen this brief memorial, even though I am a theoretical physicist and Frans was a primatologist. After all, like me, Frans believed that science is not compartmentalized into completely separate fields with no areas in common. Fields of scientific knowledge overlap and they are all united by the joy of discovery.
Indeed, Frans was a professor in a psychology department, even though he was a biologist by training—a background that affected his outlook on both his own work and on that of his colleagues. Last year, Frans sat down with me to record an in-depth discussion of his life and work, including his last book, Different: Gender Through the Eyes of a Primatologist, for my Origins Podcast. In that discussion, he confessed, “I am so happy that I work with animals who cannot fill out a questionnaire.” He was bemoaning the fact that psychology students invariably begin their research projects by creating questionnaires for their subjects (something that should immediately ring alarm bells, given the human propensity for self-delusion), rather than deciding to try to understand humans by watching their behaviour.
It is precisely this art of observing that is at the heart of good science and that helped Frans make such a profound impact on his own field, and on the public at large. From childhood, Frans loved animals and especially enjoyed observing them. During his undergraduate years, he began to work with primates. He chose to study ethology—the observation of animals in their natural habitats—an activity that he would continue for the rest of his life, thus following in the footsteps of his intellectual grandfather (his professor’s professor), the Dutch scientist Niko Tinbergen, who shared the Nobel prize in 1973 for his work on patterns of social behaviour in animals. Tinbergen (who was also the doctoral advisor of Richard Dawkins, among other distinguished biologists) once said that he was the only person who won a Nobel prize for simply watching things.
In fact, it takes a special kind of person to be good at carefully watching other animals, and Frans was a master. He once told me that one might have to observe primates for an entire day to obtain a mere three minutes of information that might lead to new insights about them. He taught the need for careful observation to his students. His former PhD student Sarah Brosnan relates: “Frans told us the best way to come up with research questions was to watch your animals and they will tell you what’s important.”
Lawrence M. Krauss
That is perhaps the most significant aspect of the intellectual revolution that Frans helped inspire. Instead of validating a priori assumptions about primates by searching for pre-selected behaviours, he let their behaviours guide his thinking. In so doing, he changed our picture of our two closest cousins, chimpanzees and bonobos, who, while they are equally closely related to us (differing from us by only 1.5 percent of their DNA) have social structures and behaviours that differ from each other in the extreme. Chimpanzees tend to be violent, solving social problems through aggression, and their social groups are patriarchal. Bonobos negotiate social problems using the currency of sex, and as Frans showed, females tend to band together to wield power in social groups.
His work revealed the roots of what had previously often been assumed to be uniquely human social behaviours—ranging from conflict resolution to reconciliation, empathy, fairness, social learning, and even hints of morality—in our primate cousins, each species of which has developed different ways of negotiating the trials and tribulations of social life.
His first major discovery showed that chimpanzees—who had previously been seen as singularly violent and aggressive—make up after fights, by kissing and embracing. He used uniquely human terms to describe this sort of reconciliation, and his work with chimpanzees led to the first of his 16 popular books, Chimpanzee Politics, which compares chimp power struggles with those of humans.
Through this, and many of his subsequent books, including Peacemaking Among Primates; Good Natured: The Origins of Right and Wrong in Humans and Other Animals; The Ape and the Sushi Master: Cultural Reflections by a Primatologist; The Bonobo and the Atheist: In Search of Humanism Among Primates; Are We Smart Enough to Know How Smart Animals Are?; Mama’s Last Hug: Animal Emotions and What they Tell Us About Ourselves; and Different: Gender Through the Eyes of a Primatologist, Frans tried to glean lessons about the origins of human nature. In so doing, he destroyed stereotypes about both primates and humans. As he said in a 2006 interview,
We have an enormous spectrum of behavior, so don’t believe claims that we are inherently nasty, aggressive, selfish and uncooperative. My argument is that we have the potential to be everything we want to be. Our job is to bring out what we want.
It is through his books and public lectures that he will most likely be best remembered, and with good reason. It was impossible to listen to him, or to read his observations about his beloved primate companions without being both captivated and surprised. His gentle demeanour was captivating, and his descriptions were thoughtful and always replete with observational examples in support of his claims, even when those claims related to subjects that might normally seem taboo.
In my book, The Physics of Star Trek, I point out that Star Trek was able to address social issues that other television programs could not—by, for example, featuring the first interracial kiss on TV—because these issues were introduced in the context of fictional societies in an imagined future. Likewise, by focusing on our primate cousins, Frans could boldly go where no primatologist had gone before. His last book, Different, allowed him to tackle the biological nature of sex and gender, a topic so fraught that academics and writers are regularly cancelled or ostracized for being perceived to be on the wrong side of the political debates surrounding those issues.
Frans’s books and lectures touched millions of people, enhancing their knowledge of the world around them, while also stirring deeply buried emotions. I am no exception. I vividly remember the first time he showed me his famous video of capuchin monkeys—later to feature in a TED talk that has 23 million views and counting—in which two capuchin monkeys, kept in adjoining cages, are fed treats for exhibiting a certain behaviour. The monkeys were perfectly happy performing their task for cucumbers until, one day, one of the monkeys was rewarded with a grape instead. When the monkey’s companion was given a cucumber for the same task, he immediately proceeded to throw a temper tantrum worthy of a three-year old child—even though, five minutes earlier, he had been content with that reward.
I immediately recognized the behaviour in myself! I showed the video to my wife, and ever since then, whenever I start to feel envious of someone for receiving any sort of reward that appears to be greater than that which I had previously been perfectly happy to receive during a similar experience, I tell myself, or my wife tells me: “Don’t be a monkey!”
I imagine that everyone who has read de Waal’s work or listened to his lectures is forever changed, at some deep level, by the experience. I can think of no higher testament to the impact of this remarkable man.
In 2014, Frans had this to say about the way his work has changed how we think about ourselves as human beings:
One thing that I’ve seen often in my career is claims of human uniqueness that fall away and are never heard from again. We always end up overestimating the complexity of what we do. That’s how you can sum up my career: I’ve brought apes a little closer to humans but I’ve also brought humans down a bit.
I am not sure I fully agree with his last sentiment. I think he raised us all by demonstrating what a human being can be capable of, over the course of a lifetime of careful observation and reflection. I shall miss him, and I expect I am not alone.
