The Nature & Nurture Podcast

Dr. Edward Hagen is a Professor of Evolutionary Anthropology at Washington State University, where he directs the Bioanthropology Lab.  In this episode, Ed and I discuss the recent controversy of the American Anthropological Association’s decision to censor a conference panel on sex differences, the reality and importance of understanding sex differences in evolutionary anthropology and biology research, and the complexity of sex beyond the binary, such as in the case of intersex disorders and different and conflicting gender norms cross-culturally. We then move on to discuss Ed’s research on the evolution of substance use, including humans’ bizarre taste for spices and bitter plant toxins such as coffee and tobacco. We also talk about the evolutionary advantages and disadvantages for the use of other psychoactive drugs, such as hallucinogens, the evolution of human intelligence, and modern computational neuroscientific theories of consciousness.

Dr. Jennifer Silvers is an Associate Professor of Psychology and the Bernice Wenzel and Wendell Jeffrey Term Endowed Chair in Developmental Neuroscience at UCLA, where she runs the Social Affective Neuroscience and Development Lab. She is an expert in adolescent brain, cognitive, and emotional development, particularly in the development of emotion regulation strategies.  In this episode, we talk about Jen’s background in developmental neuroscience, the use and limitations of animal models for understanding human brain development, and how adolescence is a particularly exciting window of brain development both due to puberty and other social and environmental changes. We talk about the role of stress and adversity influencing brain development, temperamental factors in emotion processing, emotion regulation as a learned skill, and how puberty interacts with all of these processes. We then discuss relatively recent effects on social and emotional development, such as the COVID-19 pandemic, social media use, and the influence of online dating apps in young adults’ sexual development. Lastly, we talk about other windows of rapid change influencing socioemotional processing, such as pregnancy, and future directions linking our shared interests in hormones and brain development in large-scale consortium-based studies.

Dr. Cory Clark is a social psychologist and Director of the Adversarial Collaboration Project at the University of Pennsylvania.  In this episode we talk about adversarial collaboration and open science, meta-psychology research on common biases in psychology carried by psychologists themselves, and its moralization. We also discuss gender differences in moral beliefs, how social media and culture shape moral norms, how rationality can combat this, and whether faith is compatible with rationality.

Dr. James Roney is a Professor of Psychological & Brain Sciences at the University of California, Santa Barbara, where he runs the Human Behavioral Endocrinology Lab. In this episode we talk about the proximate and ultimate evolutionary explanations of different sex hormones’ roles in coordinating motivated behavior, such as testosterone’s influence on aggression and sex drive, and ovarian hormones’ influence on sex and food drive. We discuss how testosterone leads to sex differentiation in the brain and body both prenatally and during puberty; threshold effects, rather than continuous relationships, between testosterone and motivation; the opposite effects of estradiol and progesterone on women’s sex and food motivation across the menstrual cycle. We also discuss genetic differences in the receptors to different hormones, their interactions with other hormones, and how these subtle differences may predict traits ranging from morphology to sexuality. Lastly, we discuss Jim’s recent research using daily diaries and saliva hormones to test whether daily hormonal fluctuations influence sex drive and other motivated behavior, how smell and pheromones influence attraction in males and females, and how sex hormones influence reward processing in the brain, particularly during puberty. Timestamps: 0:00:51 Hormones act as coordinators in the body 0:02:06 Example of testosterone's input and output relationships 0:05:41 Importance of understanding the inputs and outputs of hormones 0:07:43 Conservation of hormone functions from non-human species to humans 0:09:35 The role of hormones in motivated behaviors 0:11:19 Time lag between stimulus event and hormone response 0:15:19 Evolutionary theories and mating behavior tied to sex hormones 0:18:23 Evolution and psychological functions of testosterone and oxytocin 0:20:08 Understanding hormone inputs and context for coordinated effects 0:21:58 Oxytocin paradox and effects on maternal aggression 0:23:33 Confounding effects of multiple signals on hormone outputs 0:25:14 Individual variability and receptor sensitivity to testosterone 0:26:47 Genetic polymorphism and developmental calibrators of individual differences 0:28:10 Prenatal testosterone and sexual orientation 0:38:21 Threshold effects of testosterone 0:41:06 Continuous relationship between estradiol, progesterone, sex drive, and food drive in women 0:53:01 Testosterone's effect on reward may be more generalized than estradiol and progesterone 0:54:47 Estradiol may affect satiety mechanisms, not just reward systems. 0:56:56 Theoretical framework for risk taking and impulsivity. 0:58:26 Research on anxiety and depression in females during puberty. 0:59:58 Effects of testosterone on motivation and individual differences 1:08:08 Study on concealed ovulatory timing, pheromones, and scent attractiveness during ovulation

Dr. Joseph Henrich is an anthropologist and Chair of the Human Evolutionary Biology Department at Harvard University, where he runs the Culture, Cognition, and Coevolution Lab. Joe is also the author of the WEIRDest People in the World and The Secret of Our Success. Timestamps:0:00:46 Environmental factors leading to cultural evolution0:03:19 Cultural adaptations, rituals, and technological advancements0:05:11 Cultural adaptations operating outside of conscious awareness0:07:04 The role of religion in cultural transformations0:09:40 Impact of religious prohibitions on social ties0:10:59 Exploring the spread of monotheistic religions0:12:01 The expansion of gods and competition among groups0:13:55 Transition to monotheism and personification of social awareness0:16:18 Intergroup competition and tension between small and large group cooperation0:17:37 Individualistic guilt vs collectivist shame0:19:18 Variation in use of mental state terms in folktales0:23:00 Patterns in cooperation and moral judgment from human nature and cultural evolution0:24:44 Cultural evolution and species differences0:25:56 Intersection of biology and culture in sex and gender differences0:26:24 Culture changes our biology and brain0:28:28 Male inclination towards violence observed in every human society0:29:50 Testosterone levels and aggression linked to social hierarchy0:30:28 Gender paradox: greater gender equality, bigger personality/morality differences0:32:06 Sex differences observed in primates0:35:15 Fathering dynamics in human societies0:37:26 Genetic fitness and hunter-gatherer societies0:41:28 Sex ratio, crime rates, and marriage markets[0:43:32 Dating apps, competition, and inequality0:46:14 Zero sum games, land, and cultural differences0:53:18 Demographic changes and the impact on parenting styles.0:55:07 Adversity-exposed brain and its relation to life history theory.0:57:37 Using surname diversity as a proxy for diversity of thought and experience in a society.1:01:50 Linking surname diversity to occupational diversity, trust, and innovation1:04:32 Christianity's impact on scientific revolution and analytic thinking1:06:11 Bias towards progress and the concept of progress emerging

Dr. Massimo Pigliucci is a philosopher and evolutionary biologist, the K.D. Irani Professor of Philosophy at the City College of New York, a fellow of the American Association for the Advancement of Science, a prolific author of over 100 academic papers, 16 books including Evolution: The Extended Synthesis, and the best-selling How to Be a Stoic, as well as thousands of posts and short clips of wisdom on his Stoic Meditations and Practical Wisdom podcasts and Rationally Speaking blog. His research interests include the philosophy of science and evolutionary biology, the nature of psueoscience, and practical philosophies like Stoicism and Neoskepticism.

Dr. Stephanie Bugden is an Assistant Professor of Psychology at the University of Winnipeg, and an expert in the psychology and neuroscience of children's math learning. In this episode we discuss the nature versus nurture debate in math ability and the genetic and environmental influences on math learning. Dr. Bugden explains that both genetics and early learning experiences play a role in individual differences in math ability, verbal IQ, and visuospatial IQ. We also discuss whether there are sex differences in math ability at various ages, and how these differences might be confounded by math anxiety. Dr. Bugden also shares her research on the neurobiological processes involved in math learning and the challenges of studying dyscalculia, a math learning disability analogous to dyslexia. Lastly, we discuss the impact of COVID-19 on math learning and the potential exacerbation of socioeconomic inequalities in education.

Kevin J. DeBruin is a former NASA rocket scientist, a science educator and speaker, former bodybuilder and American Ninja Warrior, founder of Space Class, and author of To NASA and Beyond, and To Dare Mighty Things. In this episode we talk about Kevin’s career as a rocket scientist, life at NASA, and his story of perseverance in his books. We also discuss overlap between the mindset of engineers, bodybuilders, and self-help psychologists, sharing in common a detail-oriented focus on planning, breaking down goals into small steps, and self-discipline. We discuss other parallels between rocket science and cognitive science, such as the development of artificial intelligence, neural networks, and everyday technologies such as smartphones made possible due to technological advancements originally developed at NASA for the purposes of spaceflight. Lastly, we discuss the importance of science education, particularly from educators with deep scientific training in order to ensure effective science communication and prevent misinformation. Timestamps: 0:04:29 Kevin's journey to NASA and the challenges he faced 0:18:25 Kevin's day-to-day work life at NASA 0:25:22 Comparison between NASA and private space industry 0:35:41 Kevin's transition from NASA to science education 0:46:01 The importance of technical depth in science communication 0:52:41 The inspiration and impact of working with kids 0:56:21 The Dunning-Kruger effect and the unknown knowns 0:57:22 The connection between physics and neuropsychology 1:00:37 Overview of Kevin's book "To Dare Mighty Things"

Dr. Jonas Kaplan is a cognitive neuroscientist and faculty at USC's Brain and Creativity Institute, where he co-directs the the Dornsife Cognitive Neuroimaging Center. His research focuses on consciousness, the self, belief, empathy, social relationships, action perception and creativity. In this reunion episode, episode, we discuss active inference and predictive processing theories of consciousness, panpsychism, philosophy of mind, and the difference between interoception and exteroception. We further consider the evolutionary psychology of self-awareness, empathy, status seeking, and sexuality, and how these translate to modern technology and mental health. Lastly, we discuss neuroscience and its connection to film and literature, which Jonas discusses on his new podcast Float, and how this connects to cross-cultural analyses of religion, archetypes, and recent debates between Sam Harris and Jordan Peterson on the psychology and utility of religion. Timestamps: 0:01:30 Active inference and predictive processing 0:04:24 Skepticism about applying active inference to interoception 0:08:33 Consciousness, affect, and emotion 0:11:40 Dualism in neuroscience and philosophy of mind 0:13:41 The role of the body in consciousness and empathy 0:16:33 The limitations and challenges of artificial intelligence and empathy 0:20:09 The relationship between consciousness, narrative, and selfhood 0:26:23 Panpsychism and self-organizing systems 0:30:40 Postmodernism and categorical distinction 0:34:04 Pragmatism in statistics and narrative 0:38:08 How the brain recognizes narrative structure 0:40:32 Storytelling in hunter gatherers 0:42:04 Sexual selection, dominance, and creativity 0:49:24 The self as a collection of sub-personalities 0:52:43 Social comparison, stress, and mental health 0:55:08 Sexual selection, social status, and the crowdsourcing of wisdom 1:02:31 The psychology of dating apps 1:07:24 The potential impact of different app designs on mental health 1:09:32 The immersive experience of storytelling and audience engagement 1:13:34 The intersection of neuroscience, film, and storytelling 1:17:03 Black Mirror, technology, and memory 1:20:00 The value of forgetting and the nostalgia bias in memory 1:21:49 The cultural evolution of religion 1:25:24 Archetypes and their usefulness 1:30:40 Pantheism and mathematical Platonism 1:35:24 The necessity of axioms in science

Dr. Paul Bloom is a Professor of Psychology at the University of Toronto, and the Brooks and Suzanne Ragen Professor Emeritus of Psychology at Yale University. Paul studies how children and adults make sense of the world, with special focus on language, pleasure, morality, religion, fiction, and art. He is the author of seven books, including his latest Psych: The Story of the Human Mind. In this episode, we sample some of the many, many topics covered in Psych, including Freud, evolutionary psychology, language development, moral development, and social cognition. We also talk about Paul’s early research on language development and moral cognition, my own research on pubertal hormones and brain development, and the meta-psychology of what makes podcasts interesting. 0:00:02 Introduction to Dr. Paul Bloom and his research 0:01:10 The story behind the article "Natural Language and Natural Selection" 0:05:20 The connection between developmental psychology and evolutionary psychology 0:08:20 The concept of ontogeny recapitulating phylogeny 0:11:41 Transition from language development to moral development 0:13:42 The relationship between disgust and morality 0:16:18 The parallels between physical traits and moral traits 0:19:23 The connection between free will and moral responsibility 0:25:04 The nature-nurture debate and the role of genetics in psychology 0:31:06 The continuum of traits and the question of determinism 0:34:07 The influence of Freud and the shift towards empirical psychology 0:45:06 The history of psychology and the influence of old theories 0:55:20 The role of clinical psychology and the question of mental illness1:01:21 The psychological tendency to rationalize silver linings and find upsides in negative traits 1:06:17 Paul's role as an editor for a journal and prioritizing what to read in psychology 1:08:02 The social intimacy and connection of podcasts