41. Dr. Debra Lieberman — That’s Disgusting! Objection: Disgust, Morality and the Law

Published: Oct. 10, 2018, 1 a.m.

Why do we consider incest wrong, even when it occurs between consenting adults unable to have children? Why are words that gross us out more likely to be deemed “obscene” and denied the protection of the First Amendment? In a world where a gruesome photograph can decisively influence a jury and homosexual behavior is still condemned by some as “unnatural,” it is worth asking: is our legal system really governed by the power of reason? Or do we allow a primitive human emotion, disgust, to guide us in our lawmaking? In this wide-ranging conversation Dr. Lieberman considers disgust and its impact on the legal system to show why the things that we find stomach-turning so often become the things that we render unlawful. Shedding light on the evolutionary and psychological origins of disgust, she reveals how ancient human intuitions about what is safe to eat or touch, or who would make an advantageous mate, have become co-opted by moral systems designed to condemn behavior and identify groups of people ripe for marginalization. Over time these moral stances have made their way into legal codes, and disgust has thereby served as the impetus for laws against behaviors almost universally held to be “disgusting” (corpse desecration, bestiality) — and as the implicit justification for more controversial prohibitions (homosexuality, use of pornography).

Dr. Debra Lieberman is a Professor of Psychology at the University of Miami, where she is co-director of the Evolution and Human Behavior Laboratory. Dr. Lieberman is a leading researcher in the area of human cognition and behavior from an evolutionary perspective.

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This remote Science Salon was recorded on August 22, 2018.