According to David Moore, PhD and faculty member in the Psychological Field Group at Pitzer College, there’s good reason to believe that “genes” as we’ve come to commonly understand them don’t actually exist; they aren’t segments of DNA which start and stop at discrete points, they don’t fulfill just one role in one context, and their expression or lack thereof is not immune to environmental influences. In fact, most molecular biologists would say that there is no single agreed-upon definition of a gene. Dr. Moore joins the podcast to explore the topic of epigenetics: the phenomenon by which our experiences and environmental factors influence our genes and contribute to our characteristics. These environmental stimuli include the food we eat, how we exercise, the drugs we consume, our experiences in childhood, the level at which we socially interact as adults, and socioeconomic status. For example, a 2004 study conducted by Michael Meaney and Moshe Szyf showed an association between the level of grooming a pup receives from its mother and reactivity to stress in adulthood: the more grooming a pup received, the less reactive it was to stress stimuli as an adult. This finding, labelled by the authors as “epigenetic programming,” has been challenged by many, yet evidence that supports it continues to grow.  This is just a snippet of the fascinating conversation Dr. Moore offers, which touches on topics such as in utero epigenetics, whether epigenetic states can be changed or reversed once they’ve been established, how the most common antidepressants have been shown to produce epigenetic changes, and the controversial idea that epigenetic changes are inheritable. He also discusses his most recent research, which involves studying mental rotation in human infants—an ability considered the single biggest sex difference in cognition that’s unrelated to reproduction. Tune in for the details and visit http://pzacad.pitzer.edu/~dmoore/ to learn more.