A bonobo’s pretend tea party is rewriting what we know about imagination - ScienceDaily

June: Welcome to Kindred Minds. I'm June, a primatologist who has spent way too many happy hours watching great apes do things that make my jaw drop — and then rushing back to tell everyone about it. This show is where I share true, science-backed stories about our closest relatives on this planet, because I genuinely believe that the more you know about them, the more you understand about us. Today we have some wonderful stories to get into — a bonobo throwing an imaginary tea party, the surprising truth about what our thumbs reveal about our brains, and a finding about aggression in bonobos that might just flip your assumptions upside down. The through-line today, as always: we are more alike than we ever imagined. Before we dive in, a warm thank you to our sponsors — Ada, who helps clients integrate A I into their workflows in smart, practical ways; Ago Consulting, silicon development consulting all the way from A I to SoC; and Zen Semiconductor, an umbrella company with a remarkable portfolio across the silicon industry. Okay. Let's get into it. June: So I want to start by painting you a picture. There is a bonobo — a real, living bonobo — who, completely unprompted, sat down and began acting out a pretend tea party. She picked up an imaginary cup. She made the motions of pouring. She offered invisible refreshments to the researchers watching her. And the scientists in the room had to take a moment, because what they were watching wasn't a trick. Nobody trained her to do this. This was spontaneous, symbolic, imaginative play. And it is a genuinely big deal. June: Here's why. For a long time, pretend play — the ability to act as if something is real when you know it isn't — was considered one of those uniquely human things. It requires a specific kind of mental architecture. You have to be able to hold two realities in your head at the same time: the actual reality, and the imagined one. Psychologists call this kind of thinking "counterfactual" reasoning, or sometimes they frame it as a component of what we call a "theory of mind" — the ability to model states of the world that don't currently exist, including states in other minds. It's cognitively expensive. It's sophisticated. And we thought it was ours. June: But here's this bonobo, doing exactly that. She is treating a non-existent cup as if it were real. She knows there's no tea. She's not confused. She is playing. And that distinction — knowing something isn't real but engaging with it as if it were — that is imagination. That is the seed of storytelling, of planning, of empathy, of everything we consider the height of human inner life. June: Now, bonobos and chimpanzees are our two closest living relatives. Both species share approximately ninety-eight point seven percent of their D N A with us. Bonobos, in particular, have long fascinated researchers because of their social complexity — they have intricate relationships, they use social bonds to manage tension, and they show a remarkable range of what looks a lot like emotional nuance. So in some ways, maybe we shouldn't be surprised that imagination lives in there too. But surprised we are. And delighted. June: What researchers are now exploring is whether this kind of pretend play is more widespread among great apes than we ever tested for — because for a long time, we simply weren't looking. We weren't asking the right questions or designing the right conditions for these behaviors to emerge. And that's a humbling thought, isn't it? That we may have been underestimating the inner lives of our relatives simply because we hadn't set up the stage for them to show us. This bonobo didn't wait for an invitation. She just started her tea party. And now we have to update what we thought we knew about where imagination begins. June: And here is where I want to bring in something that might seem unrelated at first — but stay with me. There's a study that just came out linking thumb length to brain size and cognition in primates. Now, your first instinct might be to think, what does my thumb have to do with my brain? But this is actually a beautiful piece of the same puzzle. June: The research looked across primate species and found that the relative length of the thumb — specifically, how long and opposable it is compared to the fingers — correlates with brain size and with measures of cognitive complexity. The working idea here is that manual dexterity and intelligence co-evolved. They grew up together. A longer, more opposable thumb allows for what researchers call "precision grip" — the ability to hold small objects between thumb and forefinger with fine motor control. And precision grip opens up a whole world: making tools, manipulating objects, exploring the environment with your hands in intricate ways. June: That kind of hands-on exploration, over evolutionary time, may have driven selection for bigger, more complex brains. Or, another possibility, larger brains may have enabled more precise hand use, and those two things — hand and brain — kept feeding each other in this elegant, spiraling co-evolution. Either way, the thumb and the mind are telling the same story. They evolved together. They reflect each other. June: And bonobos have remarkable hands. Long thumbs, precision grip, extraordinary manual dexterity. So maybe it shouldn't surprise us at all that a bonobo can mime pouring tea into an invisible cup with apparent care and intention. Her hands were built for exactly that kind of fine, deliberate gesture. And her brain? Her brain was built right alongside them. June: This is what I love about science — the way one discovery suddenly illuminates another. A thumb study and a tea party study, published worlds apart, end up telling the same story: that the recipe for imagination, for intelligence, for inner life — it was written a long, long time ago, in biology we share. June: Alright. Let's talk biology in a deeper sense, because I want to slow down and really sit with what it means that bonobos share roughly ninety-eight point seven percent of their D N A with us. That number gets thrown around a lot, and I think it sometimes washes over people. So let me try to make it vivid. June: Your genome — the full instruction manual for building and running you — contains somewhere around three billion base pairs. These are the individual chemical letters of your D N A, the A's and T's and G's and C's. Now, ninety-eight point seven percent similarity with a bonobo means that of those three billion letters, the differences between you and that tea-party-hosting bonobo amount to roughly one point three percent. Which sounds small, right? But three billion times one point three percent is still about thirty-nine million individual differences. So there is real variation there. But here's the thing — most of your genome doesn't code for anything directly. The regions that do — the genes that build your proteins, that wire your brain, that shape your hands — those regions are even more conserved. Even more shared. June: And what's encoded in that shared D N A? Pretty much everything. The basic architecture of the brain — the regions that handle emotion, memory, social bonding, reward, planning — those are ancient structures. The amygdala, the hippocampus, the prefrontal cortex — bonobos have them. Chimpanzees have them. Gorillas, orangutans — they all have versions of these same brain structures, built from the same class of genes, doing recognizably similar jobs. June: There is actually a lovely piece of recent neuroscience that connects to this. Researchers published work in the journal Nature examining how the primate brain — and specifically a region called the putamen, which is part of the basal ganglia — integrates information from different senses in order to guide goal-directed behavior. So the putamen takes in both what you see and what you feel through touch, and it combines those signals into a unified representation of value — essentially helping the brain decide, is this thing worth going for? Is this reward worth the effort? June: Now, this research was done in non-human primates, and the findings matter because the putamen is a structure we share. Humans, macaques, bonobos — we all have this region, wired in recognizably similar ways, doing this same crucial job of integrating sensory information and translating it into motivated action. That is an ancient circuit. It predates the split between our lineages. It is part of the shared recipe. June: I find that profound, actually. When you reach for something you want — when you feel the pull of desire or the calculation of effort versus reward — you are running the same ancient software that a bonobo runs. That a macaque runs. The circuits that make us motivated, goal-oriented creatures are not uniquely human inventions. They are inherited. They are shared. We are running the same code, expressed in slightly different bodies, shaped by slightly different environments, but fundamentally — fundamentally — reading from the same instruction set. June: And I think that reframe matters. Not just scientifically, but in terms of how we see ourselves in relation to the rest of life on Earth. We didn't arrive from somewhere else. We grew from the same roots. The intelligence we're so proud of — the imagination we celebrate — it has deep, ancient, shared origins. That bonobo at her tea party isn't doing something that fell from the sky into her mind. She's doing something that evolution wrote into a lineage we both belong to. June: Now, I want to complicate something, because good science always complicates things in the best way. Let's talk about the bonobo reputation — because bonobos have a PR image that is, it turns out, somewhat misleading. June: If you've heard of bonobos at all, you've probably heard them described as the peaceful apes. The hippie apes. The make-love-not-war primates. And there's real truth in there — bonobos do use social and affiliative behaviors, including sexual behavior, to manage tension in ways that chimpanzees generally don't. Female bonobos form strong coalitions. Lethal intergroup aggression, which is documented in chimpanzees, has not been observed in wild bonobos. So the peaceful reputation has some legitimate foundation. June: But. A new study looking at bonobos in zoo settings found something that is making researchers reconsider the full picture. In those controlled environments, bonobos were actually just as aggressive as chimpanzees. The rates of aggressive behavior — things like charging, hitting, biting — were comparable between the two species. Now, this doesn't mean the peaceful bonobo narrative is simply wrong. But it does mean it's incomplete. June: Part of what this study reveals is that bonobo behavior, like all behavior, is deeply context-dependent. In the wild, bonobos live in a very specific ecological situation — they have access to abundant food, females form powerful alliances, and the social structure has evolved in ways that channel conflict into affiliative resolution rather than violence. Change the context — put them in a zoo, alter the social dynamics, shift the resource landscape — and a different behavioral profile can emerge. June: And honestly, this should feel very familiar. Because the same is true of us. Humans are not uniformly peaceful or uniformly aggressive. We are responsive. We are flexible. Our behavior is profoundly shaped by our circumstances, our social structures, our access to resources, our sense of security. Put people in desperate scarcity, remove social support, undermine alliances — and aggression can rise. Give people security, strong communities, and enough to eat — and cooperation tends to flourish. We are not hardwired to be one thing. Neither are bonobos. June: And I think that's actually the more interesting and more honest story. Bonobos are not angels. They are complex social animals, shaped by evolution to respond flexibly to their world — just like us. The old narrative that we are violent by nature and bonobos are peaceful by nature was always a little too clean, a little too convenient. The truth is messier and more interesting: both species have the capacity for aggression and for deep affiliation, and which one shows up depends enormously on the conditions. June: That's worth sitting with. Because when we talk about human nature — when we debate whether we are fundamentally good or fundamentally brutal — the bonobo story is a reminder that nature doesn't work in absolutes. We are a species capable of extraordinary violence and extraordinary kindness, often shaped more by circumstance than by some fixed inner essence. The bonobos are teaching us that. Again. June: Okay. I want to close today with something that moves me. Because we've talked about cognition, we've talked about biology, and now I want to talk about connection — about what happens in the real world when the distance between us and our primate relatives collapses entirely. June: There is a story that has stayed with me for years. It involves a gorilla named Koko — and yes, you've probably heard of Koko, but I want to tell you the part that doesn't always get told. Koko was a western lowland gorilla who was raised at the Gorilla Foundation in California, and over the course of her life she learned to communicate using a modified version of American Sign Language — she came to use over a thousand signs, and researchers documented her understanding of spoken English words in the thousands. June: But here's the moment I want to tell you about. In 1984, Koko was given a kitten as a companion — a little tailless gray cat she chose herself from a litter and named All Ball. And Koko loved that cat with something that looked unmistakably like tenderness. She carried him gently, nuzzled him, signed "soft" when she held him. A few months later, All Ball escaped and was killed by a car. When the researchers told Koko, she signed the words for "cry" and "sad" and "frown." Later, alone in her enclosure, she made a sound that the people who knew her best described as a sob. June: Now, I am careful here — I always am — because we have to be rigorous about not over-projecting human emotion onto other animals. But here is what we can say, carefully and honestly: Koko showed behavioral responses consistent with grief. She used the signs for sadness. She withdrew. She vocalized in a way associated with distress. And the neurobiological architecture for grief — for attachment and its loss — is ancient. It exists across mammals. It is part of the shared recipe. June: The capacity to bond, to mourn, to feel the absence of someone you loved — these are not human inventions. They evolved because social bonds matter for survival, and their loss is genuinely costly. That circuitry is old. Koko had it. And when she lost her small, beloved cat, something in her that was built from the same evolutionary clay as our own grief — something in her responded. June: I think about that story whenever I need a reminder of why this work matters. Not because it makes gorillas into furry humans — they aren't, and that's not the point. The point is that the feelings we consider most essentially ours — love, loss, longing — didn't appear out of nowhere when Homo sapiens arrived. They were already here. They were already woven into the fabric of the primate family we belong to. June: We share this planet with beings who feel, who imagine, who grieve, who play pretend tea parties, who are complex and contradictory and endlessly surprising. And the more we understand them — through science, through story, through simply paying attention — the more we understand ourselves. And the harder it becomes to look away from what we owe them. June: That's our episode. What a collection of stories — a bonobo with an invisible teacup, a thumb that tells the story of a mind, the complicated truth about peace and aggression, and a gorilla who taught us something about grief that no textbook could have. I hope you carry some of this with you today. I hope it makes the world feel a little more alive, a little more full of kin. June: Intelligence and feeling are not ours alone. We didn't invent them — we inherited them, along with everyone else in this extraordinary primate family. And that should fill us with wonder, and with responsibility, in equal measure. Kindred Minds is brought to you by Ada, Ago Consulting, and Zen Semiconductor — three teams of people doing genuinely interesting work, and I'm grateful for their support. If today's episode moved you or made you curious, please subscribe, leave a review, and share it with someone you think would love it. And check out the link in show notes for sources, further reading, and everything we talked about today. Until next time — stay curious, stay kind, and remember: we are all in this family together.