The Three Faces of Disgust
Understanding your behavioral immune system
Today, when we think about protecting ourselves from disease, we tend to picture vaccines, antibiotics, and clean water systems. But for most of human history, the main defenses against infection were behavioral, not technological.
For much of our evolutionary past, infections were the leading cause of death.
For both hunter-hunter gatherer societies and our nearest evolutionary relatives, chimpanzees, about seven out of every 10 deaths can be attributed to infections.
Historically, in wartime scenarios, disease killed far more soldiers than violence itself. In the American Civil War, for instance, far more deaths came from pneumonia, typhoid, and malaria than combat. The same is true during famines, when weakened bodies and unhygienic behaviors as a result of starvation kill more people than hunger itself. Even now, with all our advances, infectious diseases still account for roughly a quarter of deaths worldwide, more than twice as many as from violence or injury.
Here we’ll explore what psychologists call “the behavioral immune system,” and how it shapes modern life in ways we rarely notice. The same emotions that kept humans from eating rotten meat now shape who we trust, date, and vote for.