Episode 85: David Geary discusses our shrinking brains, cognitive development and sex differences

Today’s guest is Dr. David Geary, a cognitive developmental scientist whose wide-ranging interests are particularly focused on evolutionary psychology, sex differences and children’s mathematical development. He is a Curators' Distinguished Professor and a Thomas Jefferson Fellow in the Department of Psychological Sciences and Interdisciplinary Neuroscience Program at the University of Missouri Columbia. David’s book, “Male, Female: The Evolution of Human Sex Differences,” has been described as a landmark text that provides a comprehensive evolutionary model to explain sex differences. His research on children’s mathematical development resulted in a MERIT award from the National Institutes of Health. In addition to authoring four books, he has published more than 300 articles and chapters across a diverse range of topics. David has served as a member of the President’s National Mathematics Advisory Panel and was appointed by President George W. Bush to the National Board of Directors for the Institute for Education Sciences. Show notes: [00:02:36] Dawn asks about David’s childhood, mentioning that his family moved around quite a bit before settling down in Northern California. [00:03:00] Dawn asks if David’s early struggles in elementary school were due to jumping around from classroom to classroom because of family moves. [00:03:43] David talks about how he first became interested in science. [00:04:15] Ken asks why David decided to go to Santa Clara University in Silicon Valley. [00:04:47] David explains how he ended up majoring in developmental psychology. [00:05:18] David recounts the story of how he went from working at an auto parts store to getting his master’s degree in clinical child and school psychology at California State University. [00:06:06] Dawn mentions that before David earned his master’s degree, he went to work as a school psychologist and counselor. She then asks what led him to decide to enter the Ph.D. program as the University of California Riverside. [00:07:05] After finishing his Ph.D., David had a number of university positions before landing at the University of Missouri in Columbia. Ken asks David about the school’s interdisciplinary evolution group, which was a key reason David was interested in the university. [00:08:12] Dawn asks how children’s mathematical development and evolutionary psychology became two of David’s primary research focuses. [00:10:04] David summarizes the factors that determine human intelligence. [00:11:11] David explains why the attempt to define intelligence has always been a controversial issue. [00:11:51] Ken asks about David’s research in the ‘90s that made a distinction between evolved forms of cognition, such as language, and other forms of cognition that are more dependent on schooling, such as reading and arithmetic. [00:14:44] David talks about his interest in Evolutionary Educational Psychology, and how that relates to the insights gleaned from his recent article that argued that there is built-in scaffolding that helps a child’s mind learn to talk, use tools, and play, but that there is nothing of the sort for learning how to read, write, or do math. [00:17:14] David has been investigating children’s mathematical cognition for nearly 25 years, including a 2015 paper on the numerical foundations of young children’s mathematical development.Dawn asks David to share his key takeaways from this research. [00:20:08] David gives an overview of the MU Math Study, which is supported by the National Institutes of Health and the National Science Foundation, and focuses on mathematical development from preschool all the way through high school. [00:22:32] David discusses his research into human sex differences, and human sexual selection. [00:23:46] Dawn asks about David’s paper that focused on human cognitive sex differences, which illustrated how sexual selection can result in sex differences in the brain...