Rationality and Human Behavior – Dr. Roy | Museum of the Future: Lessons from the Past

ELI5/TLDR

Economists in the 1800s decided humans are always rational and always selfish, mostly because they couldn’t be bothered to read any psychology. A century later, psychologists looked at actual brains and found the opposite: people who lose their emotions to brain damage don’t become hyper-logical geniuses, they become paralyzed and can’t even pick a can of beans. It turns out your emotions aren’t the enemy of good decisions, they’re how your brilliant subconscious mind tells your slow conscious mind what to do. So “pure rationality” is a fantasy, and a society built on the idea that greed is smart is a society that has confused stupidity for wisdom.

The Full Story

Dr. Roy Casagranda is a political scientist who opens by sabotaging his own field. He was sick, his planned talk on the Roman Republic was too complicated, so he picked an easier subject: rationality. Easier, he says, because rationality doesn’t exist.

The game where almost everyone “loses”

He runs a classic experiment on the room. Imagine I give you 100 dollars. Your only job is to offer some of it to the person next to you. They can take it or refuse. If they refuse, you both get nothing. No negotiating, just say a number.

The textbook “rational” play is brutal: offer 1 dollar. A rational receiver should accept, because one dollar beats zero. So a rational giver keeps 99 and a rational receiver pockets the single dollar, and everyone walks away richer. That is what economics predicts.

Almost nobody does it. Most people split it roughly in half. Some refuse lowball offers out of spite, lighting the whole pot on fire to punish a stranger for being greedy. This experiment (the “ultimatum game”) has been run endlessly, and the supposedly irrational result wins every time, by a landslide.

“If you were rational, you would have said yes no matter how much because you’re going to end up with an extra dollar. So why were there any nos? There should have been 100% yeses.”

His later twist is that the “rational” lowball offer is itself irrational. Offering one dollar has a high chance of being rejected. A truly smart player anticipates the other person’s pride and offers something they’ll actually accept. Reading the other mind is the rational move.

Where the “rational, selfish human” came from

Here’s the origin story. In the 1800s economists had gotten decent at the big picture (macroeconomics) but were stuck on the individual (microeconomics): why does one person buy one thing? The sensible move would have been to ask philosophy and psychology, two fields that had been chewing on human nature for roughly 2,400 years. The economists declined. They thought philosophy was a waste of time and they disliked psychologists. So they invented an answer themselves:

“All humans are always rational and self-interested.”

Casagranda finds this absurd on contact. It can’t explain parenthood, which is self-sacrifice by design. It can’t explain Max Cleland, the Vietnam soldier who dove onto a live grenade to save his trench-mates and lost two legs and an arm. When confronted with such cases, defenders of the theory retreat to a slippery rescue: whatever you did, given your information, was the rational self-interested choice. Buy a useless 300-mph sports car? Rational, because status made you happy. But, he points out, if every behavior counts as rational, the word means nothing.

“If we are all always rational, then rationality doesn’t exist. Because for a thing to exist, the possibility that it doesn’t exist must occur.”

The same logic kills “always selfish.” He sketches a spectrum: bears, solitary creatures so antisocial a father will try to murder his own cubs, sit at one end. Ants, who build bridges out of their own bodies and let the bottom layer drown without a second thought, sit at the other. Humans are in the middle. We are a little selfish (passing wealth to our kids really does help them survive) but also wired to serve, because no human survives alone. Damage your community and you damage the soil your own descendants need. The societies that lean into mutual care report the highest happiness and longest lives; the atomized, every-man-for-himself ones report the most misery.

The idea jumps to politics, and gets worse

In 1957 Anthony Downs wrote An Economic Theory of Democracy, arguing voters could apply the same logic they use picking canned beans to picking candidates. Casagranda thinks Downs meant it as a useful lens, not gospel. Political scientists, desperate to make their field a real “science,” seized it as the answer: humans are always rational and self-interested, full stop. (He notes this is a hypothesis dressed up as a theory, and that “rat choice theory” is a fitting nickname.)

The trouble, he says, is that you can’t do physics on people. Four identical electrons under identical conditions behave identically. Four humans from four cultures will not. Social science found exactly one law: as technology rises, population rises. Then in the 1990s even that broke, as rich educated countries started shrinking. So the field had no laws and clung harder to a bad one.

The man who couldn’t buy beans

The demolition came from psychology. Antonio Damasio, both a professor and a practicing clinician, had patients with brain injuries who scored exactly the same on IQ tests afterward, yet whose lives had completely collapsed: jobs gone, friends gone, marriages gone. The common thread was that they were unbearable to deal with. Scheduling an appointment with one could take ten minutes of “how about Tuesday, no Thursday, no the week after” with no decision ever reached.

Damasio ran a quiet experiment. He told a patient he needed groceries bought for his wife’s birthday, handed over a list, and then secretly followed him. The patient got stuck. One stood in front of the canned beans for an hour, fetched a can opener and a spoon, opened cans, read labels backwards and forwards, weighing price against taste against nutrition, and dissolved into tears, unable to choose between six brands.

Brain scanning revealed the cause. The damaged region in every patient was the membrane connecting the emotion center to the rest of the brain.

“His clients didn’t have emotions. They only had logic. They only had reason. They only had rationality. And they were paralyzed.”

This is the heart of the talk. Spock, the emotionless logician we found funny on Star Trek, would in reality be a useless wreck, unable to decide anything. Emotion is not the opposite of good thinking. It is the mechanism that lets thinking finish.

Two brains, and which one is the genius

Casagranda reframes the conscious and subconscious mind. The conscious mind is the voice that won’t shut up when you try to meditate, the one narrating your worries. It’s slow, deliberate, and it has language. Useful, but not the smart one.

“It turns out your subconscious mind is a super computer… beyond comprehension genius level brilliant.”

The subconscious filters the flood of incoming data (the toy gorilla hidden in the X-ray that 95% of ER doctors never consciously notice; the torrent of inputs that lets you somehow drive a car without dying). And because it can’t talk to you in words, it speaks in emotions. The flash of regret when you grab the wrong can is your subconscious saying “no, dummy, the other one.” The hair standing up on your neck in a wrong-feeling room is a warning. The sentence that appears on the page that you didn’t quite plan, the answer that arrives once you stop straining for it, that’s the subconscious working while the chatty conscious mind finally goes quiet.

He turns this into practical advice. “Planned procrastination”: read an assignment the day you get it, then deliberately wait a few days before starting. You’re not loafing; your subconscious is processing in the background. (He’s careful to disown the self-destructive kind, leaving 24 hours for a 48-hour job.) He also reframes the old slur that women are emotional and men are logical: if that were true, it would mean women run on supercomputers and men on slow rule-followers. The real story, he argues, is that men get their emotions trained out of them, cutting off the channel their subconscious uses to communicate.

The Nobel Prizes that made it official

The psychology kept winning. Daniel Kahneman won the 2002 economics Nobel, as a psychologist, for showing that people are almost never purely rational and selfish only about half the time. A comforting assumption survived: fine, ordinary people are irrational, but leaders, the CEOs and politicians, surely they’re rational. Then Richard Thaler won the 2017 Nobel showing the elites are just as irrational as everyone else. The ancient Greeks, Casagranda notes, had already said emotion and reason temper each other; the bizarre idea that they should be divorced was a 19th-century Victorian invention.

Why it matters: bias, heuristics, and the beans again

He brings it down to earth. A Dubai taxi driver, himself an immigrant in a country that is 89% immigrant, tells him immigrants are a problem in America because they commit crimes. Casagranda counters with Texas data: native-born citizens are roughly twice as likely to commit murder as undocumented immigrants. The driver isn’t moved, because, like all of us, he formed a conclusion first and then collected only the evidence that confirmed it. That, Casagranda says, is close to the working definition of irrationality, and resisting it (“is that actually true? let me look it up”) takes years of deliberate practice.

We simplify because the world is genuinely too complex. He uses the asteroid belt and the three-body problem as a metaphor: two objects we can model, but add a third and prediction collapses. A can of beans judged on price alone is easy; price and taste and nutrition at once becomes literally incomparable, because how many pennies is a bit more taste worth? When the variables can’t be reduced to a common currency, the conscious mind stalls, and the subconscious steps in with an emotion: grab that one. Not provably optimal, but good enough.

Greed is not a virtue

He closes on the politics he’s really after. The Three Mile Island near-disaster was stopped by dumb luck, and a single safety engineer who refused to use a possibly-damaged crane (which could have triggered a fresh chain reaction) had to fight, whistleblow, and endure threats against his family, while business leaders screamed that the shutdown was costing money. That, he says, is your rational, self-interested elite.

His final target is the dressed-up justification for greed. Greed, he argues, is the dumbest instinct there is: a cockroach will eat itself to death, and he watched a pigeon eat an entire loaf of bread until its stomach ruptured. Calling greed “rational” or a “virtue” gets human nature exactly backwards. Drawing on Plato’s Republic, he sides with Socrates: the wise person does not plunder a neighbor, because weakening any member of the community weakens the whole community you depend on. We are, in the end, ants in an anthill; a species that needs maybe 10,000-20,000 people just to have the genetic and skill diversity to survive. He accuses rational choice theory of quietly mutating from describing how people behave into prescribing how they ought to behave, which makes it not a science but an ideology, a defense of capitalism mistaken for a law of nature.

Key Takeaways

The ultimatum game: when one person splits a windfall and the other can veto, the “rational” play is to offer the minimum and accept the minimum. Almost nobody does. Most split near 50/50 and many reject lowball offers out of pure spite.
The deeper point on that game: a lowball offer is itself irrational because it has a high chance of rejection. Genuine rationality includes modeling the other person’s pride and reactions.
“Rational and self-interested” was invented by 19th-century economists who explicitly refused to consult philosophy or psychology. If every behavior counts as rational, the word is empty, the same problem applies to “always selfish.”
Antonio Damasio’s patients: brain damage severed the emotion center from the rest of the brain. IQ unchanged, but they became unable to decide anything, even which can of beans to buy. Emotion is the mechanism that lets reasoning conclude.
The conscious mind is slow, deliberate, and verbal (the voice that won’t shut up). The subconscious is the fast “supercomputer.” It can’t use words, so it communicates through emotions, regret, dread, the hunch.
“Planned procrastination”: read a task immediately, then deliberately wait before starting so the subconscious processes it in the background. Distinct from leaving too little time, which is self-destructive.
The toy-gorilla X-ray study: ~95% of ER doctors miss an obvious anomaly because the subconscious filters out data tagged as irrelevant. This filtering is what lets us function (e.g. drive) amid overwhelming input.
Kahneman (2002 Nobel) showed people are rarely fully rational and selfish only about half the time. Thaler (2017 Nobel) showed business and political elites are no more rational than anyone else.
Confirmation bias as the core of irrationality: we reach a conclusion first, then gather only confirming evidence. Antidote is the trained habit of “is that actually true?” and checking a reliable primary source.
The three-body problem as a model of decision paralysis: two variables are tractable, three interacting ones become unpredictable. When variables can’t share a common unit (taste vs. price vs. nutrition), the conscious mind stalls and emotion supplies a “good enough” answer.
Greed is presented not as smart self-interest but as a primitive, self-destructive instinct (cockroach eats itself to death; pigeon eats a loaf until its stomach ruptures).
Plato’s Republic argument (Socrates): the wise person doesn’t plunder a neighbor, because weakening any community member weakens the whole community everyone depends on. Cooperation is the rational long game, even commercially.
Casagranda’s charge against his own field: rational choice theory has drifted from describing behavior to prescribing it, turning a falsified hypothesis into an ideology that launders greed as virtue.

Claude’s Take

This is a lecture, not a paper, and it shows. Casagranda is a charismatic talker who tells the story of behavioral economics with real flair, and the spine of it is solid: the ultimatum game, Damasio’s somatic-marker work, Kahneman, Thaler, the dual-process model of mind. If you’ve never encountered any of this, it’s a genuinely good on-ramp, and the Damasio material in particular is the strongest, most load-bearing part of the talk. The reframe that emotion is the enabler of decisions rather than their enemy is correct and underappreciated.

Where I’d put up guardrails: he’s loose with the science when it suits the bit. “Your subconscious is a beyond-comprehension genius supercomputer” is a fun line but overstates a real finding, the subconscious is fast and powerful and the source of most cognitive biases he’s complaining about. Kahneman’s whole point is that the fast system is what gets fooled. So “listen to your subconscious more to get smarter” sits in tension with the rest of his own argument. The “2007 fMRI changed everything” framing is breezy, and he himself admits fMRI lighting up “may or may not mean anything,” then proceeds as if it does. Some side facts are off or shaky (the Venus-becomes-Mercury aside is not real planetary science; “we’ve known about global warming for sure since 1987” is a rhetorical date).

The last third stops being about cognition and becomes a political sermon against capitalism. That’s a legitimate argument, and the Socratic “weakening a community member weakens the community” point is genuinely good, but he slides from “rational choice theory is empirically wrong” to “therefore capitalism is evil” faster than the evidence carries him. The descriptive claim (people aren’t the selfish robots the model assumes) is well supported. The prescriptive leap (so the whole system is irrational) is his politics, fairly worn on his sleeve.

A 7. Engaging, mostly accurate on the core science, a great storyteller’s tour of why “pure rationality” is a myth, but it’s a performance with enough hand-waving and ideological steering that you should chase the primary sources before quoting it as fact.