On Humans

Over half a century, Sarah Blaffer Hrdy has challenged many of our myths about parenting, attachment, and "human nature". In this conversation, we dive into her remarkable career, culminating in her new book, Father Time.[You can now order Father Time via Amazon or Princeton Uni Press]We discuss a variety of topics, from hunter-gatherer parenting to the limitations of comparing humans to chimpanzees. We also discuss "allomothers", attachment theory, and the tragedy of infanticide. We finish with a discussion on the remarkable social changes in fatherhood and the neuroscience that has enabled it. As always, we finish with Hrdy’s reflections on humanity.Timestamps(04:15) Myths(10:10) Attachment Theory (20:50) Hunter-Gatherers(24:30) Modern Parenting (26:00) Infanticide (34:00) Monkey parenting (in South America)(36:10) Why we share (40:00) Husbands, grannies, or aunties?(43:10) Father BrainsANNOUNCEMENTI'm writing a book! It is about the history of humans, for readers of all ages. Do you want access to early drafts? Become a member on Patreon.com/OnHumans⁠⁠⁠⁠⁠LINKSWant to support the show? Checkout ⁠⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠⁠Want to read and not just listen? Get the newsletter on ⁠⁠⁠⁠OnHumans.Substack.com⁠⁠⁠⁠MENTIONSTerms: allomothers, mobile hunter-gatherers (i.e. immediate return foragers), matrilineal and patrilineal kinNames: Edward O. Wilson, Robert Trivers, John Bowlby, John Watson, Charles Darwin, Mary Ainsworth, Melvin Konner, Barry Hewlett, Nikhil Chaudhary (#34), Nancy Howell, Martin Daly, Margot Wilson, Amanda Reese, Judith Burkart, Carl Von Schaik, Alessandra Cassar, Ivan Jablonka, Kristen Hawkes (#6), Ruth Feldman (#3), Richard Lee

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 in tiny 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 "maxiimum" group size natural for humans. Or so the theory goes.My guest today thinks that this is wrong. 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’ mistake(21:20) Ancient DNA of hunter-gatherers(23:20) What made H. 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.LINKSWant to support the show? Checkout ⁠⁠⁠Patreon.com/OnHumans⁠⁠⁠Want to read and not just listen? Get the newsletter on ⁠⁠⁠OnHumans.Substack.com⁠⁠⁠MENTIONSNames: Richard Dawkins, Kim Hill, David Reich, Andrea MiglianoBooks: 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 ponder 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. 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 infinityAs always, we finish with Prof Moore’s reflections on humanity.LINKSWant to support the show? Checkout ⁠⁠Patreon.com/OnHumans⁠⁠Want to read and not just listen? Get the newsletter on ⁠⁠OnHumans.Substack.com⁠⁠MENTIONSNames: 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 totalitiesBooks: 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.LINKSWant to support the show? Checkout ⁠Patreon.com/OnHumans⁠Want to read and not just listen? Get the newsletter on ⁠OnHumans.Substack.com⁠MENTIONSNames: 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.

In this enlightening discussion, Eva Jablonka, an eminent evolutionary biologist known for her work on epigenetic inheritance, delves into the evolution of consciousness. She explores the definition of consciousness and its links to evolution. The conversation raises questions about animal consciousness and the implications for AI. Jablonka highlights the complexity of conscious experiences across species, particularly during pivotal moments like the Cambrian explosion, and discusses the future challenges for consciousness in the age of technology.

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?MENTIONSNames: Elaine Aron, Helen Fisher, Stephen WrightArticles: For links to videos, articles, and the 36 Questions, see https://onhumans.substack.com/p/links-for-episode-35MORE 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.

Nikhil Chaudhary, a researcher at the University of Cambridge, shares his insights on parenting lessons from hunter-gatherer societies. He discusses how communal living and cooperative child-rearing in these cultures contrast with modern family dynamics, reducing parental stress. The conversation explores unique topics such as the roles of alloparents, the emotional complexities of parenting, and the intricate relationship between mental health and societal support. Chaudhary also reflects on how our understanding of family can evolve by looking at these traditional practices.

Helen Fisher, a Cultural Biology expert, discusses romantic love, monogamy, and maintaining passion in relationships. Topics include the evolution of romantic love, neuroscience behind relationships, animal pair bonding, and the impact of SSRIs on love. The conversation also explores mating systems, divorce patterns, and the historical significance of the plow in human society.

This is the final episode of 2023. And it is a very 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 MORETo read the full story in detail, I highly recommend Forth’s thoughtful and non-sensetationalist 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! SUPPORTPlease consider supporting the show on Patreon.com/OnHumans. MENTIONSEthnic 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