This episode is sponsored by Awesome Socks Club, a sock subscription for charity!

Click the link in the description and sign up between now and December 11th to get a new pair of fun socks each month in 2021. {♫Intro♫}. Disgust is one of our strongest, most visceral emotions.

If I simply started describing a rotting, maggot-filled piece of meat, or the smell of a milk carton that’s weeks past its expiration date, you’d probably start to feel it. And that’s the sort of disgust we’re all super familiar with. But this emotion does a lot more than that.

The darker side of disgust forms the basis for things like bigotry and xenophobia. And that’s why it’s really important to understand how this powerful emotion influences us. Scientists think disgust evolved to protect us from dangerous germs.

Before there were vaccines and antibiotics, the most effective way to avoid dying from illness was to avoid the people and things that might get you sick. Sure, you have your immune system. But it’s generally reactive, takes energy to use, and definitely isn’t perfect.

So, it might be more beneficial to just not need to invoke it. And that’s where disgust comes in. It’s thought that all of us experience disgust in basically the same way.

No matter where you grew up, when you see or smell something nasty, you make that pursed-lip face and turn up your nose. Clenching your lips could keep you from accidentally getting stuff in your mouth. And physically recoiling increases the distance between you and a potential hazard.

But not only is the experience of disgust pretty universal, what we feel disgust toward is also amazingly consistent across cultures. People tend to be disgusted by body fluids; people who are sick or dead; dirty places; and some kinds of foods, especially unfamiliar or rotten ones. Now, this isn’t to say that we always experience the exact same revulsion to the same things.

How sensitive your disgust system is can depend on your circumstances. Like, anyone who’s ever known someone pregnant knows that disgust can be majorly heightened during the first trimester, which may be an adaptation to protect the vulnerable fetus. Plus, not all of our disgust is innate.

Some of it is learned. For instance, if you get food poisoning from eating chicken, you might find chicken in general a bit disgusting going forward. Or you might learn disgust from others.

Studies have found that seeing someone else be disgusted increases the chances that you’ll feel disgust, which might explain why some foods are considered gross in some cultures but not others. In fact, a lot of our cultural norms and taboos are likely rooted in disgust. Social rules like what hand to eat with and how often to bathe probably arose as a way of keeping disgusting things at bay.

So disgust serves a lot of very useful biological purposes, but it also shapes culture. And sometimes it goes way too far. Disgust often lies at the heart of what psychologists call in-group–out-group bias—basically our tendency to break the world into “us” and “them” and favor the “us”.

Researchers think this is why the thought of sharing your mail carrier’s toothbrush is a lot grosser than sharing your spouse’s. Presumably, you already have some degree of immunity to any pathogens your spouse has, but the mail carrier could have things your immune system is totally unprepared for. But exactly who your brain considers inside and outside of this disgust circle extends far beyond who you’d lend a toothbrush to.

Throughout history, people have equated out-group members to disgusting things or implied they carry disease to justify class systems, exploitation, and even genocide. And remember how disgust can be shaped by circumstance? Well, that applies to this kind of societal disgust, too.

For instance, studies have found that people who feel more threatened by disease tend to reject outsiders more. Like, if they strongly disagree with statements like “My immune system protects me from most illnesses that other people get,” or if they live in an area with a high disease burden, they tend to hold more negative attitudes towards other racial, geographical, or cultural groups. That seems to be because disease risk strengthens bonds to family and cultural communities.

That may, in part, be because having a cohesive support network helps people survive illnesses. It may also reduce disease exposure in the first place. But disgust doesn’t just dictate who we reject.

It also shapes what behaviors we reject. Disgust is often triggered by things at odds with our sense of purity—and that extends to what we consider pure in a moral sense. People who are more sensitive to disgust generally tend to view behaviors that violate their sense of purity more harshly—something that may ultimately affect things like which policies or initiatives they support.

These moral judgements can also be shifted on the fly by getting people to feel unrelated disgust. Like, one 2011 study found that people who were exposed to something disgusting tended to make harsher moral judgments for things like stealing library books, shoplifting, and accepting bribes. So, feelings of disgust can influence everything from what we eat, to how we treat strangers, to how we vote.

But those feelings don't have to have that much power over us. One way to mitigate the effects of disgust is to reframe gross things, because how we think about the objects of our disgust matters. For example: If I told you I was going to hand you some chunky, bacteria-filled milk, you’d probably find it pretty disgusting.

But if I said I was going to hand you some yogurt, you’re probably totally okay with that. And just being aware that we have these disgust reactions to people or behaviors can help us temper them. So next time you feel a strong sense of revulsion, maybe stop and ask if your health is actually being threatened.

And if not, maybe it’s worth letting it go. Before you go, I wanted to share a time-sensitive announcement: Tomorrow is the last day to sign up for the Awesome Socks Club! The club is a charity sock subscription started by Hank and his brother John, and the idea is pretty simple: If you sign up, you get a pair of fun socks from a different designer every month in 2021.

Also, 100% of after-tax profit will go to decrease maternal and child mortality in Sierra. Leone, which is one of the most dangerous places to be pregnant in the world. You can only subscribe between now and December 11th.

So if you’re interested, click the link in the description! {♫Outro♫}.