Summer is over and the weather is getting chilly, so it’s time to turn to spicy foods to warm up—“taco trucks on every corner”, anyone?

For some, the spice is the best part while for others (the weaklings) spice makes tacos unbearable. It’s true that for those who didn’t grow up eating it, us spice-lovers are a mystery.

Peppers have been linked to the revolutionary spirit

A quick refresher: in most cases, what makes things spicy is capsaicin, the active ingredient in chili peppers, hot sauce, pepper sauce, and so on. It’s technically a neurotoxin and can be dangerous in large quantities. So why do we eat peppers and love them?

One reason might be purely evolutionary: One study from 1998 suggests that the heat of peppers also protects them from bacteria and fungi, so perhaps the relative “safety” of these foods back when sanitation wasn’t great outweighed the discomfort.

Nowadays the risk of moldy food is much lower, but the spice remains a staple in cuisine across the world. A few years ago, the psychologist Paul Rozin, most famous for his work on disgust, became interested in spice as an acquired taste. He noted that in places like Mexico, children begin to love chilies when they’re four or five. Because all the food has the sauce and animals eat leftover food in the garbage, the village animals seem to be OK with the spice too.

It’s unlikely that even the ghost pepper will actually kill you

Rozin’s theory is that we learn to like it just out of familiarity; he calls this process “hedonic reversal.” The change has nothing to do with our sensory capacity, but it’s all in the mind. It’s the same process that makes people like especially bitter coffee or wasabi.

But other research suggest that for some, it’s not just because we grew up with hot sauce, but because we specifically like the kick and the challenge. There does seem to be a link between personality and liking spicy food, according to a paper from researchers Nadia Byrnes and John Hayes at Pennsylvania State University.

They found a strong correlation between people who liked spicy food and people who scored high on the “sensation seeking” dimension of personality. These are the people who we tend to think of as being adventurous, liking roller coasters and excitement.

In fact, it’s this association that has made the pepper have a very specific reputation in China. Two Chinese provinces, Sichuan and Hunan, are especially famed for their spicy food. There, peppers represent more than just Chinese culture. “The food of the true revolutionary is the red pepper,” said Mao Zedong, who was born in Hunan. “And he who cannot endure red peppers is also unable to fight.’ ”

That said, there is one type that almost no one can endure. Bhut jolokia, also known as the ghost pepper, is one of the hottest peppers in the world. On the Scoville scale, which is used to measure capsaicin level, it tops out at over 1 million Scoville units. A jalapeño only has about 10,000 Scoville units. Every so often, we get reports about people getting sick from eating them.

But even though you might get sick — and you’ll definitely feel miserable — from eating too many peppers, it seems unlikely that even something like the ghost pepper will actually kill you. So there’s no need to fear a taco truck on every corner. I welcome it.