Why do we torture ourselves by eating spicy peppers?

Katherine Chiou, an assistant professor at the University of Alabama, explored this question and others in a presentation on her research on peppers at a Thursday event sponsored by the Stanford Archaeology Center (SAC).

(The answer, by the way, is likely because of the “high” induced by the consumption of peppers. According to Chiou, peppers bind to receptors in the brain that lead the body to pump out endorphins and increase adrenaline, creating the feeling of a “high.”)

Chiou’s talk took part as part of a speaker series that SAC has run throughout the quarter that brings scholars from across the country to Stanford to discuss their research with students, faculty and others who are interested.

“We bring in two or three visiting scholars a quarter, and we really just want to bring in people whose research specialties are perhaps slightly different than people who already have at Stanford, to foster broader communications about archeological research and the archaeological center is very interdisciplinary,” said postdoctoral scholar Kacey Chandler Grauer, an organizer of the event series.

Chiou was invited to speak about her work on peppers, which she referred to by their scientific name, “capsicum.” A trained archaeobotanist by profession, she has studied pepper seeds in Peru to determine how foodways — how social, economic and cultural practices affect consumption and production of food — for indigenous people have changed before and after colonization.

“It’s one of the few foods out there that I think hurts us,” Chiou said. “Yeah, you know that we shouldn’t really be eating because they have these mechanisms to defend against mammals like us, and yet we are. We’re obsessed with it.”

She pointed to the New Mexico and Colorado chili pepper preference rivalry as an example, and our obsession with a YouTube show called “Hot Ones” where celebrities eat chicken wings with increasingly spicy hot sauce while answering questions about themselves.

Chiou explained that peppers originated in Latin America, where, according to archaeological records, there was a diverse selection for different types of peppers. It was only after Spanish colonization and the Columbian Exchange that peppers spread across the world, becoming staples in cuisines ranging from Sichuanese to South Korean to Mexican, she said.

Chiou’s research has largely centered on Peru’s aji amarillo, the yellow pepper that Peru is best known for.

The seeds are fundamental to her research: Chiou said the aji amarillo has become the dominant pepper species in Peru. The speciation — formation of new species through evolution — of ancient and modern peppers is key to understanding how they moved around from the Americas in prehistory and now. Her research involves comparing archaeological specimens of pepper seeds to more modern chili peppers based on their shape and size.

Chiou said that there still remain many unknowns about what pepper species may have looked like pre-colonization. It can be difficult to reconstruct ancient peppers, she said, since pepper seeds can be charred and easily change shapes. The question of when peppers were first domesticated continues to remain unanswered and debated among scholars.

Chiou and other researchers continue to seek insight into why people used peppers in the past and continue to do so today, as well as the evolution of peppers from pre-colonization periods to now.

“We’re doing other things right now with a whole bunch of people including geneticists, colleagues and a whole group of students,” she said.