You're Sweaty and Miserable. You're Still Not a Monster.
A sweeping five-country experiment just upended one of behavioral science's favorite assumptions: that heat makes us meaner. It doesn't.
Here's the scene: a researcher secretly cranks a lab room up to 34°C (that's 93°F for the Americans), then watches 1,636 participants across five countries sweat through a series of economic games. The hypothesis? That people baking in miserable heat would get stingier, more aggressive, and more selfish.
The results? Nothing. Well, almost nothing. People were definitely hot. They were frustrated. They were tired and unhappy. They just kept playing fair anyway.
Culture, for one. American participants showed a dramatically higher tolerance for unequal outcomes than participants in Kenya, India, Colombia, or Mexico, who consistently favored equal splits. These differences held even after controlling for income and individual life satisfaction — they appear to reflect something deeper, something baked in over generations of shared norms.
Gender, for another. Women were more egalitarian, less competitive, and less focused on personal payout than men — consistently, across all five countries. The gender gap in competitiveness was especially stark; men were significantly more likely to enter a tournament format in every country except Kenya.
Temperature? It didn't crack the top predictors in any model.
So What Actually Predicts How We Treat Each Other?
The researchers are careful not to toss out decades of evidence linking warmer temperatures to higher crime and civil conflict. That link is real. What this experiment challenges is the assumed mechanism: the tidy story that heat directly frays our social instincts, making us turn on each other. Instead, the data point toward indirect pathways — resource scarcity, prolonged exposure, alcohol, and compounding social pressure. A controlled lab room strips most of those variables away. So does a one-hour session. What happens after weeks of unrelenting heat and shrinking water supplies is a different, and harder, question.
But Doesn't Heat Cause Violence? Yes — Just Not Like This.
For now, the clearest takeaway is a humbling one for anyone who thought the climate crisis would turn humans into selfish brutes simply by raising the thermostat: the evidence doesn't support it. The things that determine how we treat strangers — culture, upbringing, gender, norms — are far sturdier than that. They survived a sweaty afternoon in a lab in five countries. That's nothing.