All Episodes

August 20, 2025 113 mins

Nancy Segal (Deliberately Divided: Inside the Controversial Study of Twins and Triplets Adopted Apart) is an evolutionary psychologist, behavioral geneticist, and author. Nancy joins the Armchair Expert to discuss whether there’s anything predictable about a twin who comes out first, why in twin studies differences are not deficits, and her work with the Minnesota Study of Twins Reared Apart. Nancy and Dax talk about the unexpected reason identical twins are more alike that any other pair of people, the concept of inclusive fitness to explain differential genetic behavior, and why doppelgängers can be an effective test for criticism of twin research. Nancy explains her argument that twins fundamentally challenge how we think the world works, the remarkable fact that children born on the same day to two sets of identical twins are genetic fraternal twins, and why only identical twins raised apart are able to see themselves in a life unlived.

Follow Armchair Expert on the Wondery App or wherever you get your podcasts. Watch new content on YouTube or listen to Armchair Expert early and ad-free by joining Wondery+ in the Wondery App, Apple Podcasts, or Spotify. Start your free trial by visiting wondery.com/links/armchair-expert-with-dax-shepard/ now.

See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Mark as Played

Advertise With Us

Popular Podcasts

Stuff You Should Know
My Favorite Murder with Karen Kilgariff and Georgia Hardstark

My Favorite Murder with Karen Kilgariff and Georgia Hardstark

My Favorite Murder is a true crime comedy podcast hosted by Karen Kilgariff and Georgia Hardstark. Each week, Karen and Georgia share compelling true crimes and hometown stories from friends and listeners. Since MFM launched in January of 2016, Karen and Georgia have shared their lifelong interest in true crime and have covered stories of infamous serial killers like the Night Stalker, mysterious cold cases, captivating cults, incredible survivor stories and important events from history like the Tulsa race massacre of 1921. My Favorite Murder is part of the Exactly Right podcast network that provides a platform for bold, creative voices to bring to life provocative, entertaining and relatable stories for audiences everywhere. The Exactly Right roster of podcasts covers a variety of topics including historic true crime, comedic interviews and news, science, pop culture and more. Podcasts on the network include Buried Bones with Kate Winkler Dawson and Paul Holes, That's Messed Up: An SVU Podcast, This Podcast Will Kill You, Bananas and more.

The Joe Rogan Experience

The Joe Rogan Experience

The official podcast of comedian Joe Rogan.

Music, radio and podcasts, all free. Listen online or download the iHeart App.

Connect

© 2025 iHeartMedia, Inc.