“Morality isn’t just about stealing and killing and honesty, it’s often about menstruation, and food, and who you are having sex with, and how you handle corpses,” says NYU social psychologist Jonathan Haidt, who is author of The Righteous Mind: Why Good People are Divided by Politics.

Haidt argues that our concern over these victimless behaviors is rooted in our biology. Humans evolved to feel disgusted by anything that when consumed makes us sick. That sense of disgust then expanded "to become a guardian of the social order.”

This impulse is at the core of the culture war. Those who have a low sensitivity to disgust tend to be liberals or libertarians; those who are easily disgusted tend to be conservative.

Haidt discussed his views on morality and politics at an event hosted by the Reason Foundation, which was held on February 19, 2013 at the Museum of Sex. Haidt's lecture was followed by a Q&A with New York Times Science Columnist John Tierney.

Approximately 35 minutes. Camera by Jim Epstein and Naomi Brockwell. Edited by Epstein.

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