Podcast Summary: You Are Not So Smart – Episode 327

Title: The Trolley Solution – Joshua Greene
Date: November 24, 2025
Host: David McRaney
Guest: Dr. Joshua Greene (Experimental Psychologist, Neuroscientist, Philosopher, Harvard)

Overview

This episode delves into the intersection of moral philosophy, psychology, and neuroscience through the lens of the famous “trolley problem,” featuring guest Dr. Joshua Greene. Host David McRaney explores how Dr. Greene’s scientific work has not only advanced our understanding of moral decision-making but has been translated into practical solutions aimed at reducing polarization and increasing societal cooperation—including innovations in charitable giving and a cross-tribal cooperative game called “Tango.” The episode balances theory and actionable applications, making the abstract deeply tangible.

Key Discussion Points & Insights

1. Dr. Joshua Greene’s Path to Moral Science

• Background and Origins
  • Greene’s childhood fascination with debating and philosophy morphed into a scientific career via exposure to philosophy courses and influential figures like Stephen Jay Gould and Antonio Damasio.
  • Early curiosity about why pushing a man off a bridge feels morally different from pulling a switch in trolley dilemmas led him to seek biological explanations (18:07–24:13).
    • “I got really just stuck on this because I was like, why does it seem okay to hit the switch but not okay to push the guy?... And I got really into this.” – Greene [18:59]
• The Trolley Problem as a Bridge from Philosophy to Neuroscience
  • Greene’s epiphany: The emotional aversion in the footbridge scenario is connected to brain structures damaged in Phineas Gage, highlighting the biological underpinnings of moral judgments.
  • This led to fMRI studies and the landmark “trolley problem” paper in Science, sparking his interdisciplinary career (18:59–24:21).

2. Moral Psychology and the Structure of Moral Judgments

• How the Brain Processes Moral Dilemmas
  • Emotional aversion (linked to the amygdala and ventromedial prefrontal cortex) plays a major role—particularly when actions are direct, intentional, and violent.
  • People with VMPC damage (like Gage) or certain personality traits (psychopaths, expert meditators) are more likely to make utilitarian choices, showing less aversion to sacrificing one for many (29:48–35:26).
    • “If harm is active rather than passive...if you are using the person as a means...and the physical directness of harm—all of these interact to shape our intuitions.” – Greene [29:48]
  • Cultural and experiential factors (training, meditation) can modulate these responses.
• Scientific Progress on Old Philosophical Problems
  • Greene advocates for dissolving some philosophical dilemmas into empirical psychological questions (25:22–29:01).
    • “A lot of philosophical problems are what you could very loosely call the front of the brain arguing with the back of the brain.” – Greene [25:27]
  • Morality can and should be studied scientifically—it's brain stuff, not just metaphysics.

3. Scaling Morality: From Tribe to Planet

• Modern Moral Dilemmas and the Scale of Impact
  • Advances in technology and interconnectedness mean that individual and institutional decisions now affect people on a massive, often distant scale (36:38–39:02).
    • “We have the incredible power to help people or hurt people on a massive scale from a distance. And that is the scariest thing...and also the greatest opportunity.” – Greene [37:22]
• Tragedy of Common Sense Morality
  • Greene introduces his concept: Classical “tragedy of the commons” meets modern group conflicts (“the tragedy of common sense morality”).
  • Different tribes, each with their own “common sense,” encounter conflict over shared resources and values—solving this requires a “metamorality,” a higher-order system for group coexistence (39:13–44:23).

4. Translating Science into Solutions

A. Charitable Giving and “Giving Multiplier”

• Greene’s research shows that while people want to give emotionally to causes they feel connected to, they also value effectiveness.
• The solution: Allow people to “split” their donation—half to their chosen charity, half to a vetted, highly effective charity, with matching funds as incentives (45:47–54:50).
  • “When you give people the 50-50 split, they get the feeling of supporting that thing that they really care about...and you kind of get both kinds of satisfaction.” – Greene [47:43]
• Impact: Experiments demonstrate dramatically increased giving to effective charities when bundling and matching are offered.
• Led to the creation of Giving Multiplier, facilitating this behavioral nudge, raising millions for high-impact causes.

B. The “Pods Fight Poverty” Campaign

• Runs in collaboration with GiveDirectly, Ologies, The Happiness Lab, and others.
• Focus: Direct cash transfers to impoverished families, shown to have powerful immediate and long-term effects.
  • “For every dollar, there’s a 2.5x multiplier for the local economy. So when people have money to spend and invest, it brings up everybody around them.” – Greene [56:41]
• Special offer for listeners: Donations via GiveDirectly.org/smart are matched 50% through Giving Multiplier (54:50–58:16).

C. The “Tango” Game – Engineering Cross-Tribal Cooperation

• Inspired by principles from both biology and social psychology: teamwork and contact theory.
• Tango is a digital cooperative quiz game that pairs participants from different ideological backgrounds (e.g., Republicans and Democrats).
  • “It’s this quiz game where you are paired up with someone, ideally who’s different from you...” – Greene [59:26]
• Game design encourages complementary knowledge and positive interaction before introducing political questions. Cooperation builds empathy and trust, validated by longitudinal studies (59:26–73:55).
  • “When people play this game just once, we see positive effects...effects that last four months.” – Greene [69:11]
  • Memorable moment: David recalls a spark of teamwork over a Garth Brooks trivia question, highlighting how shared victories lead to genuine in-group feelings [73:00].
• Soon to be rolled out more broadly via bots and online scheduling (letstango.org).

Notable Quotes and Memorable Moments

• On solving philosophy via neuroscience:
  “What I love most about what you’re up to is when a philosophical argument becomes a scientific investigation.” – McRaney [24:35]

• On the evolution of moral disputes:
  “What looks like metaphysics...I was seeing psychology. They were seeing impossible conundrum about the way the world is and trusting their perceptions...I wanted to ask where are those perceptions coming from?” – Greene [27:42]

• On why deep cooperation works:
  “Everything...is a product of cooperation and competition at increasing levels of complexity. Individuals form tribes and chiefdoms and nations and occasionally United Nations...there’s cooperation at every level too. And that cooperation...it's sustained because there’s gains of trade.” – Greene [59:26–61:00]

• On the intended impact of Tango:
  “What the cooperative experience does is it gets people in the space where they can say, okay, we may disagree, but we can see each other’s humanity...If we can get to the point where millions more people see the other political side not as an untrustworthy enemy...we will get through this adolescence that we’re in as a democracy.” – Greene [76:16]

Important Timestamps

• 01:22 – Introduction to Dr. Joshua Greene and the trolley problem
• 17:39–24:21 – Greene’s life story and entrance into moral psychology
• 24:35–29:16 – Bridging philosophy and empirical science
• 29:48–35:26 – Neuroscience of moral judgments (trolley findings)
• 36:38–39:02 – Scaling morality to societal/national/global issues
• 39:13–44:23 – The “tragedy of common sense morality” and need for “metamorality”
• 45:47–54:50 – Boosting charitable impact through donation bundling and Giving Multiplier
• 54:50–58:16 – Pods Fight Poverty and the GiveDirectly campaign
• 59:26–77:24 – “Tango” game: theory, mechanics, results, scaling solutions

Final Takeaways

• Dr. Greene’s work showcases the power of interdisciplinary thinking—using brain science to address timeless moral conundrums and translating them into practical tools that foster cooperation and reduce polarization.
• Listeners are invited to act on these insights by donating via GiveDirectly.org/smart and exploring the upcoming game at letstango.org.
• The episode’s hopeful message: While our brains evolved for tribal morality, through science, empathy, and clever institutional design, it is possible to expand our moral circle and build a better, more cooperative society.

For full links, donation options, and more, visit the episode page or check your show notes.