Gustave Le Bon’s The Crowd: A Study of the Popular Mind (1895) has had the half-life of uranium. His thesis is simple and disturbing: rational individuals become irrational when they merge into a crowd. The crowd hypnotises, contagion spreads, and reason dissolves in the swell of collective emotion.
It’s neat. It’s elegant. It’s also far too flattering.
Le Bon assumes that the default state of the human being is rational, some Enlightenment holdover where citizens, left to their own devices, behave like tidy mini-Kants. Then, and only then, do they lose their reason in the mob. The trouble is that a century of behavioural science has made it painfully clear that “rational man” is a fairy tale.



Daniel Kahneman mapped our cognitive machinery in Thinking, Fast and Slow: System 1 (fast, intuitive, emotional) is running the show while System 2 (slow, deliberate, logical) is mostly hired as the PR manager after the fact. Dan Ariely built a career documenting just how predictably irrational we are – anchoring, framing, sunk-cost fallacies, you name it. Add in Tversky, Thaler, Gigerenzer, and the usual suspects, and the picture is clear: we don’t need a crowd to become irrational. We start irrational, and then the crowd amplifies it.
In that sense, Le Bon wasn’t wrong about crowds being dangerous, but he may have missed the darker point. A crowd doesn’t corrupt a rational base – it accelerates the irrational baseline. It’s not Jekyll turning into Hyde; it’s Hyde on a megaphone.
This matters because if you take Le Bon literally, the problem is situational: avoid crowds and you’ll preserve reason. But if you take Kahneman seriously, the problem is structural: crowds only reveal what was already there. The positive feedback loop of group psychology doesn’t replace rationality; it feeds on the biases, illusions, and shortcuts already baked into the individual mind.
Le Bon handed us the stage directions for mass manipulation. Modern behavioural economics shows us that the script was already written in our heads before we ever left the house. Put the two together and you have the perfect recipe for political spectacle, advertising, and algorithmic nudges.
Which makes Le Bon’s century-old observations correct – but not nearly bleak enough.