Usually when someone is disgusted by something, he feels it is unpleasant and stays away from it, so disgust mostly protects people from getting sick. However, getting a little dirty can have its advantages. Studies show that kids under age one who physically interact with a dog will have a 13% reduction in the likelihood of developing asthma, a breathing problem.
In the late 1860s, Charles Darwin proposed that being disgusted could have a developmental purpose. 1[■] He guessed that the early humans most likely to feel disgusted survived to pass on their genes (基因), while the more nutritionally daring died off.
2[■] It wasn’t until the early 1990s, a time when gameshows eagerly slimed contestants, that disgust got more attention in psychological and behavioral research. Since then, scientists have identified different types of disgust and have explored how they affect the way we behave.
The research shows that Darwin was basically right: disgust is a major part of the behavioral immune system that protects people from disease, a collection of actions influenced by some of the most natural reactions that keep our bodies in superior condition. We already know that not all germs (病菌) are bad for us. 3[■] Science also tells us that getting a bit dirty helps people more readily fight disease.
“Disgust is associated with fewer infections, so it is a helpful emotion in disease-relevant contexts,” says Joshua Ackerman, an associate professor of psychology at the University of Michigan. However, he says it can be a double-edged sword. 4[■] And some of those things could actually improve our health.
5[■] Disgust is part of society’s balance. Too little, and we might get sick. Too much of it can harm our health. Figuring out this complex problem could help researchers understand a variety of human behaviors.