On Humans

Modern cities are unique. Never before have so many people lived so close to each other. But just how unique is our modern cosmopolitanism? Completely unique, says a traditional theory. Humans evolved to live in groups. These groups were not only smaller than modern cities. They were smaller than medieval towns. Indeed, hunter-gatherers often move in bands of 25 people or so. These bands might draw people from a "meta-group" of 150 people — but not more. And so, 150 people is the natural group size for humans. Or so the theory goes. My guest today disagrees.  Cecilia Padilla-Iglesias is an evolutionary ecologist who studies hunter-gatherer societies. And her work points to a very different conclusion. Yes, hunter-gatherers spend much of their time in small bands. But these bands can form much larger groups of connections, extending further and further away, even to areas with different languages. Even in the rainforest, cosmopolitanism is the norm. So what do hunter-gatherer societies look like? And are they really good models of our deep past? We discuss these and other topics in this episode, touching upon topics such as: (04:00) Living with hunter-gatherers (10:30) Fluid societies (14:20) Dunbar’s mistake  (17:20) Dawkins’s mistake (21:20) ANcient DNA of hunter-gatherers (23:20) What made Sapiens special?   (25:40) Mobility, diversity, and technology (28:20) Sympathy and xenophobia (34:00) Ancient DNA (again) (41:30) Jungle cosmopolitanism (43:40) Was agriculture a mistake? As always, we end with my guest's reflections on humanity. LINKS Want to support the show? Checkout ⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠ Want to read and not just listen? Get the newsletter on ⁠⁠⁠OnHumans.Substack.com⁠⁠⁠ MENTIONS Names: Richard Dawkins, Kim Hill, David Reich, Andrea Migliano Books: God Delusion (Dawkins), Who We Are And How We Got Here (Reich), The Human Swarm (Moffett) Ethnic groups: Bayaka (Congo), Hadza (Tanzania), Ache (Paraguay), Agta (Philippines) Articles: For links to articles, see OnHumans.Substack.com/p/Links-for-Episode-39-Hunter-Gatherer

Infinity is a puzzling idea. Even young children are fascinated by its various manifestations: What is the biggest number? Does the universe have an edge? Does time have a beginning? Philosophers have tried to answer these questions since time immemorial. More recently, they have been joined by scientists and mathematicians. Indeed, a whole branch of mathematics has become dedicated to the study of infinity.  So what have we learned? Can we finally understand infinity? And what has this quest taught us about ourselves?  To explore this topic, I am joined by philosopher Adrian W. Moore.  Professor Moore is a special guest for two reasons. First, he is a world expert on infinity, known for an excellent BBC series, "History of the Infinite". More personally, he is the head tutor of Philosophy at St Hugh’s College, Oxford, where I studied my BA in Philosophy and Psychology. It has now been ten years since Prof Moore interviewed me and, for whatever reason, accepted me as a student. I feel honoured to mark the occasion with this episode. In this episode, we discuss: (02:35) Why infinity fascinates (12:20) Greeks on infinity (20:05) A finite cosmos?  (25:00) Zeno’s paradoxes (32:35) Answering Zeno (42:35) Measuring infinities? Georg Cantor (54:05) Infinity vs human understanding (66:20) Mystics on infinity As always, we finish with Prof Moore’s reflections on humanity. LINKS Want to support the show? Checkout ⁠⁠Patreon.com/OnHumans⁠⁠ Want to read and not just listen? Get the newsletter on ⁠⁠OnHumans.Substack.com⁠⁠ MENTIONS Names: Aristotle; Zeno; Archytus; Ludwig Wittgenstein; Kurt Gödel; Alan Turing; Georg Cantor; William Blake; Immanuel Kant  Terms: Pythagoreans; Zeno’s paradoxes; calculus; transfinite arithmetic; counting numbers, i.e. positive integers; absolute infinities, or inconsistent totalities Books: The Infinite (Moore) Other scholarship: For games on infinite boards, see e.g. the work of Davide Leonessi: https://leonessi.org/

Why are we furless? Why do we cook our food and use spoken language? And how does climate change, sashimi, or the banks of Central America relate to human origins?  Human evolution is a deeply puzzling topic. But behind this dense mist lies many keys to our self-understanding. To guide us through the foggy territory, I am joined by Dr Ian Tattersall, a curator emeritus at the American Museum of Natural History (New York). In this episode, Dr Tattersall and I discuss: (04.00) An ancient climate change (07:20) First humans (11:20) Fire (17:50) Fish (21:40) Rocks (24:00) Evolution vs Innovation (25:30) Brain growth (36:10) Children (39:50) Language (48:20) Why? As always, we finish with Dr Tattersall's reflections on humanity. LINKS Want to support the show? Checkout ⁠Patreon.com/OnHumans⁠ Want to read and not just listen? Get the newsletter on ⁠OnHumans.Substack.com⁠ MENTIONS Names: Richard Wrangham (see ep. 21), Susan Schaller, Ildefonso, Jane Goodall, Sarah Blaffer Hrdy, Yuval Noah Harari  Books: Masters of the Planet (Tattersall), Man Without Words (Schaller), Sapiens (Harari) Technical terms: Oldowan tool culture (first stone tools, c. 2.5 million years ago), Acheulean hand axe (first major update in stone tools, c. 1.6 million years ago) Fossils: Lucy (3.2 million years old); Turkana Boy (aka. Nariokotome Boy, 1.6 million years old) Hominin species: Australopithecines, Homo ergaster, Homo erectus, Homo heidelbergensis, Homo neanderthalensis, Homo sapiens A note on hominin taxonomy: Homo habilis was traditionally considered the first human and the first maker of stone tools. Dr Tattersall is among the many critics of this old idea. According to him and many others, there is no separate tool-making species called Homo habilis. Rather, Australopithecines started making stone tools without any change in the biology of the species. Also, it is worth noting that Dr Tattersall rejects the traditional view which gives a big role for Homo erectus in the human story. In this traditional view, Turkana Boy’s species, Homo ergaster, is called an African Homo erectus. Dr Tattersall and many others argue that this is a historic hangover with little basis in the biological evidence.

We are conscious creatures. But why? Why did consciousness evolve? Can we use biology to explain the origins of feeling and meaning? Or will consciousness forever escape the grip of the scientific method?  Eva Jablonka has thought hard about these issues. An eminent evolutionary biologist, she became famous for her pioneering work on epigenetic inheritance. More recently, she has produced very original work on the evolution of consciousness with her colleague, neuroscientist Simona Ginsburg. So invited him on the show to discuss the evolution of consciousness, or what she beautifully calls "the sensitive soul". In this episode, we discuss themes such as: (03:00) What is consciousness?  (10:45) Four links between evolution and consciousness (27:30) Are robots conscious? Consciousness and vulnerability (30:45) Which animals are conscious? Consciousness and the Cambrian Explosion. (34:30) Can science fully explain consciousness? (48:00) The future of consciousness As always, we end with Jablonka’s reflections on humanity. LINKS Want to support the show? Checkout Patreon.com/OnHumans Want to read and not just listen? Get the newsletter on OnHumans.Substack.com MENTIONS Books: Evolution of the Sensitive Soul, Picturing the Mind (both my Eva Jablonka & Simona Ginsburg) Terms: Sensitive soul, phenomenal consciousness, intentionality (i.e. "aboutness"), the Cambrian explosion, cephalopods, anthropods, vertebrates Names: Aristotle, Simona Ginsburg, Jonathan Birch, Antonio Damasio

Why do we love? What brings us together? How to heal ethnic hatred? According to my guest, the answer to all these questions lies in the human desire to grow ourselves through connecting with others. Arthur Aron is a psychologist who studies human bonding in all its forms. A pioneer in the field, he has studied topics from connecting with strangers to maintaining romance in life-long marriages. And many of his findings are ultimately hopeful. In this conversation, we discuss topics such as: (4:30) Why we love  (12:50) Tools to cultivate love (24:30) Friendships with the ethnic "other”  (31:30) Are we naturally xenophobic? MENTIONS Names: Elaine Aron, Helen Fisher, Stephen Wright Articles: For links to videos, articles, and the 36 Questions, see https://onhumans.substack.com/p/links-for-episode-35 MORE LINKS Read the On Humans newsletter at OnHumans.Substack.com Support On Humans at Patreon.com/OnHumans

Can evolution shed light on our mental health? Nikhil Chaudhary thinks so. He is an anthropologist at the University of Cambridge who specialises in the links between evolution and psychiatry. In this clip, Dr Chaudhary explores the evolutionary origins of ADHD, depression, and anxiety. For our longer conversation on parenting and family life, see episode 34 of the On Humans Podcast.

We expect a lot from parents, especially from mothers. “Maternal instincts” are such, we are told, that mothers should gain almost literal superpowers from the joy of parenting.  Unfortunately, many parents face a different reality. Having children can be one of the most stressful times of life, amplified by feelings of guilt and inadequacy.  Why is this? Is this an inevitable part of the human condition? Or is the fault in our modern society? And how would we know the answer?  To address these questions, anthropologists have started comparing family lives in industrial societies with those of the last remaining hunter-gatherers.  Nikhil Chaudhary is one such anthropologist. A researcher at the University of Cambridge, he recently co-authored a remarkable paper on what we have learned about the family lives of hunter-gatherers. I invited him on the show to discuss the findings and their implications. So what is family life like amongst hunter-gatherers? Chaudhary's research paints a fascinating picture. Indeed, industrial societies can learn a lot from them. But not everything is easy for them, either. In addition to parenting, our conversation touched upon themes from monogamy and polyamory to parental grief, health spending, and the stark contrast between human and chimpanzee mothers. MORE RESOURCES If you enjoy our conversation and want to learn more about hunter-gatherer studies, see episode 14 with Vivek Venkataraman. For more information on the anthropology of monogamy and beyond, see episode 11 with Helen Fisher.  For written content on this and other conversations, subscribe to the newsletter at OnHumans.Substack.com.  MENTIONS Names: Sarah Blaffer Hrdy (see upcoming episode this spring), Richard Wrangham (see episode 21), Alan Watts  Terms: Partible paternity, alloparenting, post-partum depression, the continuum concept, NHS (UK’s National Health Services), human self-domestication (see episode 21) Ethnic groups: BaYaka (both the Mbendjele in Congo and the Aka in CAR), Ache (in Paraguay), Hadza (in Tanzania), Agta (in the Philippines), Bantu peoples (the major ethnolinguistic group in most southern African countries) Articles: For links to articles mentioned in this conversation, see https://onhumans.substack.com/p/links-for-episode-34 SUPPORT You can support the On Humans podcast by becoming a member at Patreon.com/OnHumans

Happy New Year 2024! To celebrate the new year, Spotify sent me a bunch of data points about 2023. I was particularly interested in one question: which conversation moved people the most? I already knew which episode people played the most. (That's episode 17 with Bernardo Kastrup.) But to listen is one thing. To share with friends and family is another. The most shared episode was my conversation with Helen Fisher, titled "A Cultural Biology of Sex, Love, and Monogamy". It was one of my favourite conversations, too. Fisher offered a sweeping take on romantic love, combining fascinating anthropology with practical tips about maintaining passion in relationships. She even convinced my parents to re-design their TV arrangement... Perhaps it deserves one more share. So here you go! ___ ORIGINAL SHOW NOTES Why do we love? And how much does our culture shape the way we do so? In this episode, Ilari talks with Helen Fisher about the powers that drive and shape our romantic relationships. Ilari and Professor Fisher discuss: Is romantic love a modern invention? Is monogamy a social invention?  Do men care more about sex? Do women care more about romance? Why agriculture, especially with the plough, caused havoc in romantic relationships. Why divorces might be on the decline. A science-based guide for maintaining romantic relations (based on couples who are still in love after 25 years) Why (certain) antidepressants can kill the sex drive and blunt romantic love (to read more, see the end of the notes) How common is polygamy or polyandry? Where in the world do we find most "free love"? Why did homosexuality evolve? Names mentioned Irenäus Eibl-Eibesfeldt (as recounted by Alison Gopnik in her The Gardener and the Carpenter) Bill Jankowiak Robert Sternberg (see episode 7) Anderson Thompson Bertrand Russell  Technical terms and ethnic groups mentioned Ventral tegmental area VTA Hypothalamus Dopamine, testosterone, oxytocin, vasopressin, serotonine Monogamy (serial or lifelong; social or biological) Polygamy (several wives) and polyandry (several husbands)  Tlingit (the polyandrous Inuit society with wealthy women) Oneida community (in New York State) Dig Deeper Antidepressants: To read more about the possible effects of SSRIs on sex drive and romantic love, see ⁠Tocco and Brumbaugh (2019)⁠. Below is a list of possible alternatives or complements to SSRIs (please consult with your doctor in all matters related to pharmaceuticals): Fisher herself suggested that SNRIs could be less risky than SSRIs. Theoretically, dopamine reuptake inhibitors, such as bupropion, could also counter the risks associated with SSRIs (for a review, see ⁠Zisook et al. 2006⁠). For alternative or complementary oral treatments of depression, see research on supplementation with a high dosage of Omega 3 (EPA and DHA, not ALA) (for a review, see ⁠Bhat & Ara 2015⁠). Polyamory: In the episode, Professor Fisher suggests that many Amazonian tribes have informal polyandry, i.e. women have many partners, albeit only one formal husband. However, there are ⁠non-academic sources⁠ suggesting that formalised polyandry is common in the Zo’é community in Amazon. For some of these photos of Zo’é and other Amazonian tribes, many of whom exhibit remarkably liberal attitudes to sex, see the ⁠recent Amazonia exhibition⁠ in the London Science Museum.

This is the final episode of 2023. And it is an odd episode. My guest is Gregory Forth. He is an anthropologist who specializes in the biological theories of indigenous peoples. Forth was doing this work on the Flores Island, Indonesia, during the 2003 discovery of a new hominin species: Homo floresiensis. This was an exciting discovery for many. But Forth was, in his own words, "gobsmacked". In his own studies, Forth had been puzzling over a species the local people called lai ho'a, a creature that was not quite human and not quite monkey. It was something in between. According to the local people, the lai ho'a live deep in the local rainforest. They are difficult to see. But people do see one occasionally. They are about a meter in height, just as Homo floresiensis. And they walk on two legs – a feature that separates humans from other mammals. So what should we make of all of this? Could Homo floresiensis, or its descendants, still be alive? Or is this just another fantasy in the realm of cryptozoology? And what would it be like to encounter a species that is half human, half ape? What rights would they get? How would it challenge our ideas about "humanity"? This is my attempt at making sense of this peculiar case. I hope you enjoy it! READ MORE To read the full story in detail, I highly recommend Forth’s book, ⁠Between an Ape and Human: An Anthropologist on the Trail of a Hidden Hominoid. I am now publishing episode breakdowns, essays, and much more. Read online or sign up for the newsletter on ⁠OnHumans.Substack.com⁠!  SUPPORT Please consider supporting the show on Patreon.com/OnHumans. MENTIONS Ethnic groups: Lio People (on Flores), Southeast Asian “Pygmies” (i.e. indigenous people with very short stature) Hominin species: Homo floresiensis, Austrolopithecine, Homo erectus, Homo neanderthalensis, Homo denisovans, Homo sapiens

Capitalism can cause massive economic inequalities. Indeed, a century after Adam Smith wrote the Wealth of Nations, the richest 1% owned a record-breaking 70% of England’s wealth. Not surprisingly, this era saw the rise of a very different economic theorist: Karl Marx. [You can see this and many other graphs here.] But does capitalism have to increase inequality? If so, why was the golden age of American capitalism an era of rapidly decreasing inequality? Was this “Great Levelling” a natural product of capitalist development, as theorised by Simon Kuznets? Or was it a historical anomaly resulting from the two world wars and political interventions, as argued by Thomas Piketty? Yet more questions emerge if we take a more global outlook. Was the Great Levelling within rich countries but a veil behind which they plundered the Global South, making capitalism an inherent engine of global inequality? If so, why has global inequality reduced during the recent era of globalised capitalism? There are very few people who can judge these questions with the same nuance and understanding as Branko Milanović. Milanović is a leading scholar of global inequality. But he is also a particularly sensitive commentator on capitalism. Born in communist Yugoslavia, Milanović has a rare ability to look at capitalism from an arms-length, without indoctrinated faith but also with a deep appreciation of the limits of its alternatives.  I hope you enjoy our conversation! VISUAL DATA We discuss a lot of numbers in this episode. You can find a lot of relevant graphs in my Substack post: https://onhumans.substack.com/p/the-evolution-of-inequality-under To follow Milanović's own work, and get a lot of more graphs, see his many books and his blog "Global Inequality" at https://branko2f7.substack.com/ SUPPORT I hope you enjoy the conversation. If you do, consider becoming a supporter of On Humans on ⁠⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠⁠.  MENTIONS Names: Karl Marx, Alexis de Tocqueville, Brad DeLong (see episode 18 & season 1 highlights), Simon Kuznets, Arthur Berns, Thomas Piketty,  Gabriel Zucman, Emmanuel Saez, Jason Hickel, François Quesnay, Adam Smith, David Ricardo, Vilfredo Pareto Names: Gini coefficient, Kuznets-curve, Mondragon (a Spanish cooperative), homoploutia (when the rich both own capital and work for an income)  Books: Visions of Inequality (Milanovic), Capital (Marx), Capital in the 21st Century (Piketty), Global Inequality (Milanovic), Capitalism, Alone (Milanovic)

The tension between science and religion is perhaps the greatest tension of our age. Is the world fundamentally made of atoms, quarks, and quantum fields? Or is the material world but a secondary realm, lesser in meaning to the kingdom of God? There are many iterations of this tension. But there are also bridge-builders; thinkers who want to bridge science and religion — or at the very least, science and spirituality. My guest today is one of them. Donald Hoffman is a vision scientist, who has come to the dramatic conclusion that space and time are not fundamental. They are, according to him, just parts and parcels of our perception. Therefore objects, molecules, and atoms are not fundamental. Consciousness is. We explored the scientific case for Hoffman's theory in episode 30. In this 2nd part, we explore its relationship with spirituality. What if Hoffman is right? Should we live our lives any differently? What is the meaning of life in a world without space or time? Do we find God behind Hoffman's mathematics? You can enjoy this conversation without listening to the previous one. ESSAYS AND NEWSLETTER You can now find breakdowns and analyses of new conversations from ⁠⁠OnHumans.Substack.com⁠⁠. SUPPORT I hope you enjoy the conversation. If you do, consider becoming a supporter of On Humans on ⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠.  MENTIONS Names: Albert Einstein, Rupert Spira, Dalai Lama (H.H. the 14th), Joseph Dweck Terms: Canor's hierarchy, entropy

The world is governed by objective laws of physics. They explain the movements of planets, oceans, and cells in our bodies. But can they ever explain the feelings and meanings of our mental lives? This problem, called the hard problem of consciousness, runs very deep. No satisfactory explanation exists. But many think that there must, in principle, be an explanation. A minority of thinkers disagree. According to these thinkers, we will never be able to explain mind in terms of matter. We will, instead, explain matter in terms of mind. I explored this position in some detail in episode 17. But hold on, you might say. Is this not contradicted by the success of natural sciences? How could a mind-first philosophy ever explain the success of particle physics? Or more generally, wouldn't any scientist laugh at the idea that mind is more fundamental than matter? No — not all of them laugh. Some take it very seriously. Donald Hoffman is one such scientist. Originally working with computer vision at MIT's famous Artificial Intelligence Lab, Hoffman started asking a simple question: What does it mean to "see" the world? His answer starts from a simple idea: perception simplifies the world – a lot. But what is the real world like? What is “there” before our perception simplifies the world? Nothing familiar, Hoffman claims. No matter. No objects. Not even a three-dimensional space. And no time. There is just consciousness. This is a wild idea. But it is a surprisingly precise idea. It is so precise, in fact, that Hoffman’s team can derive basic findings in particle physics from their theory.  A fascinating conversation was guaranteed. I hope you enjoy it. If you do, consider becoming a supporter of On Humans on ⁠Patreon.com/OnHumans⁠.  ESSAYS AND NEWSLETTER You can now find breakdowns and analyses of new conversations from ⁠OnHumans.Substack.com⁠. Subscribe to the newsletter to get every new piece to fresh from the shelf. MENTIONS Names: David Gross, Nima Arkani-Hamed, Edward Whitten, Nathan Seiberg, Andrew Strominger, Edwin Abbott, Nick Bostrom, Giulio Tononi, Keith Frankish, Daniel Dennett, Steven Pinker, Roger Penrose, Sean Carroll,  Swapan Chattopadhyay Terms (Physics and Maths): quantum fields, string theory, gluon, scattering amplitude, amplituhedron, decorated permutations, bosons, leptons, quarks, Planck scale, twistor theory, M-theory, multiverse, recurrent communicating classes, Cantor’s hierarchy (relating to different sizes of infinity... If this sounds weird, stay tuned for full episode on infinity. It will come out in a month or two.) Terms (Philosophy and Psychology): Kant’s phenomena and noumena, integrated information theory, global workspace theory, orchestrated objective reduction theory, attention schema theory Books: Case Against Reality by Hoffman, Enlightenment Now by Steven Pinker Articles etc.: For links to articles, courses, and more, see https://onhumans.substack.com/p/links-for-episode-30

How natural is a sexual division of labour? Very natural, claims a popular theory. Indeed, it was the secret to our success: men evolved to hunt, women to forage. This allowed women to focus on childcare while staying economically productive; after all, one can gather food with children. Men, on the other hand, could focus on high-risk hunting. At the end of the day, everyone could have steak and veggies for dinner. But why exactly do we say this? Is this based on solid evidence? Or are we simply projecting our gender roles onto the human past? A recent piece in Scientific American argued that this theory is outdated and should be "buried for good". As you might imagine, some heated discussion ensued. This is understandable. But I felt that much of the science was lost under the storm. To clean things up, I invited one of the authors, Cara Ocobock, to discuss the paper on the show. I hope this can clarify the argument. It might even clear some of the unnecessary controversy. At the very least, this was a very stimulating discussion! I learned a lot of things, from the remarkable lifestyle of female Neanderthals to how oestrogen helps in muscle recovery.  I hope you enjoy the conversation! If you do, consider becoming a supporter of On Humans on Patreon.com/OnHumans.  ESSAYS AND NEWSLETTER Do you prefer reading to listening? You can now find breakdowns of new conversations from OnHumans.Substack.com. (This conversation's breakdown is now available!) MENTIONS Scholars: Sarah Lacy, Cara Wall-Sheffler, Vivek Venkataraman (ep. 14), Frank Marlow, Kristen Hawkes (ep. 6), Angela Saini, Richard Wrangham (ep. 21) Terms: archaeology, physiology, paleoanthropology, Holocene, Pleistocene, atlatl (spear-thrower), CT scanning, lactation, testosterone, oestrogen  Ethnic groups and places: Martu (Australia), Agta (Philippines) Inuit, Batek (Malaysia), Çatalhöyük (Turkey) Books: Patriarchs (Saini), Why Men (Lindisfarne & Neale), Dawn of Everything (Graeber & Wengrow) For articles and other links, see https://onhumans.substack.com/p/links-for-episode-29 Thank you, as always, for listening!

“Why do we care about equality? Is it an invention of the European Enlightenment? Or is it something rooted in human nature?” These questions launched episode 15 with philosopher Elizabeth Anderson. Titled “A Deep History of Equality”, our conversation ranged from Pleistocene hunter-gatherers to Chinese communism.  Today’s episode continues the quest. But this time, we go further and contrast humans to other apes and monkeys.  My guest is the primatologist Sarah Brosnan. Her research is famous for a wildly popular video clip of a monkey who, frustrated by unequal treatment, throws a cucumber at the experimenter. You might have seen the video. Do watch it if you have not. It's only 58 seconds long. https://www.youtube.com/watch?v=-KSryJXDpZo I saw this clip years ago. It resonated with something in me. But what exactly? Why should we care about monkeys throwing cucumbers? Are the critics right who say that this has nothing to do with human values? It was an honour to discuss this with Prof Brosnan herself. We start by exploring cucumber throwing (i.e. "inequity aversion") in a variety of species. We then move to topics such as: Can monkeys learn more egalitarian social norms? How do monkeys (or chimpanzees) react to unfairness when they are the ones benefitting? Answering the critics: is this really about social equality? Does fairness improve cooperation? Are there property rights in the primate world? Is there still something special about humans? As always, we end with my guest's reflections on human nature. I hope you enjoy the conversation! NEW OFFERING Do you prefer reading to listening? Or would you like to revisit the argument’s highlights? You can now get breakdowns of this and other episodes directly to your email. Subscribe via the On Humans SubStack or read on the web. The breakdown of this conversation is available now! NAMES Malini Suchak / Frans de Waal / Julia Neiworth / Erin Musto / Friederike Range / Jason Davies / Michael Tomasello / Felix Waerneken  LINKS For links to mentioned papers and talks, see https://onhumans.substack.com/p/links-for-episode-28. SUPPORT THE SHOW ⁠⁠⁠⁠https://www.patreon.com/OnHumans⁠⁠⁠ GET IN TOUCH ilari@onhumans.org

The human brain is sometimes called the "most complex thing in the universe”. It allows us to study ourselves, other animals, and the cosmos itself. Indeed, we often think of our brain as the pinnacle of animal evolution. But what do we actually know about the human brain? How different is it from the brain of an elephant? A chimpanzee? A raccoon? And if our brain is not the biggest in the animal kingdom (it is not), then what, if anything, makes it worth the hype? To discuss this topic, I am joined by the Brazilian neuroscientist Suzana Herculano-Houzel. An associate professor at Vanderbilt University, Herculano-Houzel has done more than perhaps any living human to help us understand these questions. And her work has a wonderful capacity to explain why the human brain is so remarkable, but simultaneously, why it still fits within the broader patterns we see in other animals. (That’s unlike the elephant, the raccoon, or the chimpanzee. Their brains are truly special, she says.) Herculano-Houzel’s work also suggests an answer to what might be the biggest question in human evolution: If a big brain is a good idea, why didn’t all other animals grow one? As always, our conversation finishes with my Herculano-Houzel’s reflections on humanity. Thank you, as always, for listening! (You can also keep scrolling down to find some useful bits, such as useful links and lists of terms, names, and numbers mentioned in the episode conversation. Or do you prefer reading to listening? Or wish to get back to some highlights? From the 5th of October onwards, you can also read a breakdown of this conversation on Substack⁠.) LEARN MORE To get longer show notes (plus essays based on the episodes), subscribe to On Humans on Substack. https://OnHumans.substack.com/ To get highlights in video format, check out On Humans on YouTube. https://www.youtube.com/@OnHumansPodcast Patreon supporters can access more bonus material. ⁠⁠⁠⁠https://www.patreon.com/OnHumans⁠⁠⁠ MENTIONS Technical terms The (cerebral) cortex / The cerebellum / Neurons / Stereology / The grandmother hypothesis (see episode 6)   Names Harry Jerison Numbers Neurons in the whole brain of humans (86 billion) and elephants (257 billion) Neurons in the cerebral cortex of humans (16 billion), great apes (6-8 billion), elephants (5-6 billion), dolphins & whales (1-4 billion, based on estimations), baboons (2- 3 billion), t-rex (2-3 billion based on estimates), smaller monkeys (1-3 billion), raccoons (over 1 billion), crows (a notch less than 1 billion) Links T-rex video: ⁠https://www.youtube.com/watch?v=a1tEnm53zDs⁠ Herculano-Houzel’s TED talk (viewed almost 4 million times): ⁠https://www.ted.com/talks/suzana_herculano_houzel_what_is_so_special_about_the_human_brain?language=en⁠ SUPPORT THE SHOW You can support the show for free by sharing episodes, subscribing to the show, and rating it on Spotify and Apple Podcasts. To show some serious support, join the group of wonderful people supporting the show financially. ⁠⁠⁠https://www.patreon.com/OnHumans⁠⁠ Get in touch: ilari@onhumans.org

How literally can we be in "synch" with someone? Very literally, said my guest in episode 3. Originally titled “A Musical Biology of Love”, this was a fascinating episode with jazz musician and neuroscientist Ruth Feldman. We recorded the episode one year ago, almost to the day. I have thought a lot about it ever since. So here it is again, with remastered audio and a new introduction. Original show notes are below. Enjoy! ____ SUPPORT THE SHOW Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program. Visit: ⁠⁠⁠⁠Patreon.com/OnHumans ⁠⁠⁠⁠ Get in touch: ilari@onhumans.org _____ Can biology expand our appreciation of love? What is the relationship between jazz and neuroscience? What does it mean to be in "synch" with someone?  Ruth Feldman is a professor of neuroscience at Reichman University, Israel, with a joint appointment at the Yale Child Story Centre. A jazz musician before being a neuroscientist, Feldman combines musical ideas of synchrony into her research on the neurobiology of attachment, bonding, and love. Ilari and Professor Feldman discuss topics such as: Why study the biology of love What happens in the brain when we love Brain-to-brain synchrony: How love (and friendship) can synchronize our brains with each other Oxytocin with loved ones, strangers, and enemies Post-partum depression Parental love in gay dads Females and males as primary caregivers The relationship between brain-to-brain synchrony and oxytocin Empathy within and beyond group boundaries with Israeli and Palestinian youth Attachment theory, attachment problems, and ways to overcome them Technical terms mentioned Oxytocin Brain oscillations (i.e. brain waves) EEG (a method to study brain oscillations) Neuropeptide ⁠Kangaroo care⁠ (after premature birth) Names mentioned Wallace Stevens (American poet) Emmanuel Levinas (French philosopher) John Bowlby (founder of the attachment theory) Other links and reference ⁠Brain-to-brain synchrony⁠ Gay dads: ⁠original research⁠ & ⁠TIME Magazine article⁠ ⁠Intervention with depressed moms⁠

Machines allow us to do more work with less effort. They sound like an obviously good thing. But there is a tension here. New gadgets and new technologies - new simple “machines” - have been invented throughout history. But it looks like the living standard of the average person did not change for most of that time. So what happened to all the extra output from new technologies? And how is this relevant to our age of computers, robots, and AI?  To discuss these themes, I am joined by MIT professor Daron Acemoglu. Acemoglu is a true legend in his field. In 2015, he was ranked the single most cited economist of the past 10 years. And his most famous book, Why Nations Fail, (co-authored with James Robinson) is known by many students of economics as the only history book they ever had to read.  But today’s conversation is not about Why Nations Fail. It is about Acemoglu’s new book, Power and Progress: Our 1000-Year Struggle Over Technology (co-authored with Simon Johnson). In many ways, this is a typical Acemoglu book: it is a doorstopper that uses an array of historical lessons to draw messages for the present. And as before, it asks economists to take democratic politics more seriously. But in other ways, this is quite different from his previous books. For me, it felt much darker – especially in its portrayal of rich countries such as the US. But Acemoglu affirmed to me that he is still an optimist. He even tells me that the reason is related to the theme of this podcast series... I will let him tell you why. We discuss topics such as: Why have so many machines failed to benefit the common folk?  Why things changed for the better in the late 1800s - and why my past guests are wrong about the reasons? Have we started backsliding again?  Does this explain the political turmoil of today - especially in the US? Why Acemoglu is not against technological progress - but has a message to tech leaders  What has his work in economics taught Acemoglu about humanity? ____ SUPPORT THE SHOW Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program. Visit: ⁠⁠⁠⁠Patreon.com/OnHumans ⁠⁠⁠⁠ Get in touch: ilari@onhumans.org _____ Oded Galor (episodes 12 & 13), Brad DeLong (episode 18) / Josh Ober / Ian Morris / Samuel Bowles / Herbert Gintis /John Hicks / H. J. / Robert Allen / Habakkuk / Joel Mokyr / Elon Musk / Pascual Restrepo Other terms and references Malthusian dynamics (of population growth “eating away” any increases in production)  Chartists and Luddites (19th Century British political movements)

To complete a trilogy on the anthropology of war, here is episode 8 from the archives. Enjoy! SUPPORT THE SHOW Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program. Visit: ⁠⁠⁠⁠Patreon.com/OnHumans ⁠⁠⁠⁠ Get in touch: ilari@onhumans.org _______ Thomas Hobbes famously wrote that life in the state of nature was “nasty, brutish, and short”. Recently, various scholars have claimed that Hobbes was basically right: our ancestors lived in a state of constant raiding and chronic warfare. Indeed, some have suggested that as many as 15% of ancestral humans died due to war. And the claims are made with the utmost confidence. But there is something disturbing about this confidence. The earliest archaeological records of war are only c. 14,000 years old. And many anthropologists working with modern-day hunter-gatherers claim that they tend to be remarkably peaceful.  The literature around this question is dense and difficult to penetrate. This episode aims to make it a notch more accessible.  Douglas P. Fry is an anthropologist and a leading scholar on the topic. He has written extensively about the origins of war in books such as War, Peace and Human Nature. His papers on the matter have been published in top journals such as Science. And his conclusions might be surprising to many. In this discussion, Ilari and Professor Fry talk about: The archaeological evidence for the origins of war. Why do some hunter-gatherers wage war? Why does Fry think that most of them do not? And why is the data in ⁠Better Angels of Our Nature⁠ so misleading - even fabricated? How common is lethal violence in mammals more generally?  How violent was the human Pleistocene (over 11,700 years ago)? Does it matter? Ethnic groups mentioned Pacific Northwest hunter-gatherers (hunter-gatherer groups well-known for having complex “civilisation”, including social hierarchies, warfare and slavery) Calusa (a complex hunter-gatherer group in Florida) Tiwi (Australian hunter-gathers who are atypical for having clans and a high level of lethal violence) Andaman Islanders (in the Bay of Bengal) Iñupiaq (the warring Inuit group, which was not named in the discussion) Names and technical terms Herbert Manscher Jane Goodall (primatologist who recorded so-called Gombe wars in chimpanzees) Steven Pinker  Samuel Bowles  Leslie Sponsel  Christopher Boehm C. Darwent, J. Darwent  References Misreported “war deaths” in Better Angles of Out Nature (⁠Fry & Söderberg 2019⁠) and lethal violence in hunter-gatherers (⁠Fry & Söderberg 2013⁠) Lethal violence in mammals (⁠Gomez et al. 2016⁠) and in archaeological skeletons (⁠Haas & Piscitelli)⁠  Cooperation in a spatial prisoner’s dilemma (⁠Aktipis 2004)⁠ Peace systems (⁠video⁠ & ⁠the Nature article⁠)

Is war natural for humans? This question launched episode 8 of this podcast. In that episode, anthropologist Douglas Fry argued that war is a new phenomenon. Yes, history is full of wars. But war arrived on stage only 10-15 thousand years ago – or in many areas, much later. And while war is undoubtedly part of human capacity, it is hardly our hardwired inclination.  But what about chimpanzees, I asked him. They wage war. And according to many chimpanzee experts, they gang up on strangers whenever they can do so with ease. Does this not show that humans, too, are biologically programmed for feuding, raiding, and eventually, warfare? Is it not the case, then, that peace is a social invention – war the biological norm? No, Fry answered. But to understand why, he told me, I must wait until his colleague releases a book on the topic.  That book is out now. Chimpanzee, War, and History is written by Fry’s long-time collaborator, R. Brian Ferguson. It goes through every chimpanzee killing on the record. And it argues that chimpanzee violence has been deeply misunderstood. The book was detailed, dense, and important. It was an eye-opener for me. So it was a pleasure to have Professor Ferguson come on the show to talk about it.  We touched upon questions such as: How often do chimpanzees kill others?  Why do chimpanzees kill others (when they do)? Is human impact the only reason for chimpanzee wars? Do chimpanzees and humans enjoy violence? Does war go forever back?  ____ SUPPORT THE SHOW Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program. Visit: ⁠⁠⁠Patreon.com/OnHumans ⁠⁠⁠ Get in touch: ilari@onhumans.org _____ Scholars mentioned  Albert Einstein / Sigmund Freud / Michael Ghiglieri / Richard Wrangham; episode 21 / Brian Burkhalter / Leslie Sponsel / Douglas Fry; episode 8 Chimpanzee groups Kahama and Kasakela group (in Gombe)  K- and M-groups (in Mahale) Ngogo (in Kibale) Other links  Video of a chimpanzee raid (narrated by David Attenborough) Essays, articles, and other materials by R. Brian Ferguson are available on his personal website

What does war do to the human psyche? It can traumatise. It can cause grief. It can normalise violence and make demons out of the enemy. But difficult times can also elevate our care and compassion. And while much of the new solidarity is focused on those on “our side”, the helping hand does not always stop at the border. Or so argues anthropologist Greta Uehling, the author of Everyday War (2023). Building on over 150 interviews with Ukrainian civilians and ex-combatants, Uehling’s work brings depth and nuance to the topic - a topic often simplified by naive contrasts between peaceful care and brutal violence. Profoundly optimistic in ways, Uehling is still far from romanticising war. Rather, she paints a humane picture of people finding meaning from the challenges of violent conflict. Dr Uehling sat down with Ilari to discuss various stories and lessons from Ukraine. As always, the episode finishes with Dr Uehling's own views on humanity. Mentioned scholars Yuval Noah Harari / Paul Ricoeur / Hans-Georg Gadamer Names of the Ukrainian respondents have been altered to protect their identity _________ SUPPORT THE SHOW Please consider becoming a supporter of On Humans. Even small monthly donations can make a huge impact on the long-term sustainability of the program. Visit: ⁠⁠⁠Patreon.com/OnHumans ⁠⁠⁠ Get in touch: ilari@onhumans.org