El Podcast

E180: Attraction & Disgust: Evolutionary Psychology Explained (Dr. Deb Lieberman)

Episode Summary

Dr. Debra Lieberman, an evolutionary psychologist at the University of Miami, explains how “mental apps” like disgust and attraction evolved to solve survival and mating problems—often beneath our awareness. We dig into what people find attractive (symmetry, fertility/resource cues, kindness), why incest avoidance can be triggered by growing up together, and how disgust shapes food, sex, social judgment, and even law.

Episode Notes

Evolutionary psychologist Debra Lieberman explains how “disgust” and other built-in mental programs shape attraction, kinship, morality, and even law—while modern technology and social media scramble the cues those systems evolved to track.

Guest bio:

Dr. Debra Lieberman is a professor of psychology at the University of Miami and an evolutionary psychologist who studies how evolved “mental apps” shape social life—kinship, cooperation, morality, sexuality, and emotions. She’s the co-author of Objection: Disgust, Morality, and the Law.

Topics discussed:

• What makes someone “hot”: symmetry, hormonal cues, and universal vs learned templates
• Male vs female mate preferences (fertility cues; resource/provisioning cues; kindness/safety)
• Disgust as an evolved system for pathogen avoidance (food, touch/contact, sex)
• Incest avoidance, the Westermarck effect, kibbutzim and “minor marriages” evidence
• Sexual reproduction, pathogens, and why “mixing the gene pool” matters
• How disgust bleeds into moral judgment and law; coalitions and social leverage
• Why modernity/tech changes the payoff of ancient intuitions
• Gratitude as a “sleeper” universal emotion that jumpstarts friendship
• Her evolutionary psychology textbook + MediaByte project

Main points:

• Attraction isn’t “simple”—it’s output. Your brain runs hidden machinery that converts cues into a gut-level “hot/not.”
• Symmetry functions like a health certificate. It’s hard to build a symmetric body; disruption from disease/mutations makes symmetry informative.
• Men’s and women’s preferences differ on average, but share a template. Men track fertility-linked cues; women track resource acquisition/investment cues—plus kindness/safety as a major predictor.
• Disgust is a multi-purpose regulator. It steers eating, contact, sex, and social avoidance by tracking contamination risk and other fitness costs.
• Incest avoidance relies on cues, not DNA tests. Early co-residence can trigger “this is kin” psychology even when people aren’t related (Westermarck effect).
• Modern abundance doesn’t erase ancient wiring. People calibrate to local “baselines” and still compete relative to that baseline.
• Moral disgust can be weaponized. Disgust language can rally coalitions (“those people are disgusting/bad”) and support punishment, including via law.
• Gratitude is an underappreciated social engine. It flags “this person values me more than expected,” helping form alliances beyond kin.

Top quotes:

• “Beauty is in the adaptation of the beholder.”
• “We’re not frogs… we have a very specific human operating system that guides us toward certain features and away from others.”
• “Symmetry is hard to build—it can act like a kind of health certificate.”
• “Women track resource acquisition… but one of the most critical traits is kindness—it signals safety.”
• “You smell something off and you don’t eat it—you’re not thinking ‘pathogens’… you’re thinking ‘ew’.”
• “There’s no one-size-fits-all disgust; it depends on what you were calibrated to as ‘normal.’”
• “If morality were just cooperation… why wouldn’t heterosexual men celebrate gay men for reducing competition?”
• “Gratitude is triggered when someone shows they value you more than you expected—it jumpstarts friendship.”