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A pleasure to burn: Why do people like spicy foods?
Spicy foods are enjoyed the world over, but scientists don't know why people partake in culinary masochism.
- Humans are the only animals known to willingly eat foods that cause irritation, discomfort, and even pain.
- Theories for why range from thrill-seeking behavior to an evolutionary adaptation for seeking foods that reduce pathogens.
- Taste results from an interplay of genes, culture, memory, and personality, a complex design that scientists are only now beginning to understand.
If a Martian anthropologist found its way to a Clifton Chili Club Chili Eating Contest, it would discover one the universe's true oddities. Here, it would witness a group of bipedal primates cheering on other primates as they torture themselves with fruits that set their mouths on simulated fire.
By extraterrestrial standards, the rules are simple. The competition asks participants to nosh a chili pepper to the stalk. If they quit, throw up, or drink a glass of milk — which sits before them with tantalizing temptation — they are disqualified. Each round introduces a new pepper of increasing "pungency," that burning heat as measured by the Scoville scale.
Things start easily enough with the dainty Padron pepper, which averages around 500 Scoville heat units (SHU). By round 3, participants enjoy a classic jalapeno (3,000-6,000 SHU). Round 9 introduces the habanero (300,000 SHU). At this point, most participants are suffering inflamed eyes and molten saliva draining into their eruptively churning stomachs. The culling has begun.
In the final round, three competitors squared off against the Carolina reaper, the world's hottest chili. Averaging 1,641,183 SHU, it is more than 250 times hotter than a jalapeno.
Which leads our Martian anthropologist to ask, why? Even setting aside the extremes of a chili eating contest, why do people all over the world enjoy spicy foods or any food that causes pain and irritation? What is going on with these funny Earth animals?
Capsaicin is for the birds
A marine undergoes pepper spray training. The ingredient that gives pepper spray its debilitating sting, capsaicin, is the same ingredient that gives chilies their beloved fire. Image source: Cpl. Neysa Huertas Quinones/U.S.A Marine Corp
The truth is scientists — human scientists, that is — don't know how people acquired a taste for tortuous cuisine. They're not even sure why peppers began to sport capsaicin, the molecular compound that triggers your tongue's pain sensors, in the first place.
Some evidence suggests that pepper plants use capsaicin as a mammalian repellent. That may seem odd, as most plants try to entice animals to spread their seeds with sweet flesh and enticing colors — not detract them with promises of a seared tongue.
But mammals' strong stomach acids break down pepper seeds, reducing the plants' fecundity. Birds' digestive tracts, on the other hand, allow the seeds to pass through unharmed and be dispersed widely. Not coincidentally, birds aren't sensitive to capsaicin. Their taste receptors don't register its pungency.
There is also evidence that capsaicin is a natural antifungal. Studies have shown that pepper plants in fungal-rich environments produce more of the compound than those from drier environments.
Both theories explain the evolutionary advantages capsaicin provides the pepper planet. We simply don't know which one, or perhaps another, was the impetus for the pepper plant to favor capsaicin-fueled fruit.
Those who favor fire
The world's hottest pepper, the Carolina reaper, features a warning red color and a malicious looking spike, practically daring thrill seekers to give it a go. Photo credit: Wikimedia Commons
Getting back to people, there are several vying theories as to how humans developed a taste for pain. One is that we simply enjoy the thrill of it. Dr. Paul Rozin, professor of psychology at the University of Pennsylvania, argues that people use spicy foods as a type of "constrained risk" or "benign masochism."
Eating spicy foods triggers a mild defense response in us. Our heart rates rise, our breathing increases, and our adrenaline starts to flow. We feel alive. It's the same thrill-seeking behavior exhibited by bungee jumping, roller coasters, and horror movies. The thrill of pain rejuvenates us, while we secretly know all will be well in the end.
The Eastnor Castle Chili Festival Chili Eating Contest seems to support Rozin's theory. While some people can get a thrill out of a roller coaster, others need to jump off a bridge with a literal lifeline tied to their legs. Similarly, while some people can get a jolt from a jalapeno or habanero, others require the Carolina reaper to jump start their heart. And as we desensitize ourselves to one thrill, a more extreme one must then take its place as evinced by the eternal quest for an ever-hotter pepper or mouth-melting hot sauce.
Add to that the sense of camaraderie and community that naturally comes with food, and our Martian anthropologist may yet understand the ritual.
"Humans and only humans get to enjoy events that are innately negative, that produce emotions or feelings that we are programmed to avoid when we come to realize that they are actually not threats," Rozin told the New York Times. "Mind over body. My body thinks I'm in trouble, but I know I'm not."
Further supporting Rozin's theory is that all other mammals avoid spicy, painful foods. In fact, we know of only one other mammal that shares a taste for peppers: the Chinese tree shrew. But tree shrews aren't nature's chili-heads. It has instead evolved taste receptors that makes it less sensitive to capsaicin, thus expanding its food options. In other words, the shrew doesn't take pleasure in a smoldering snack like we do.
An acquired taste
A spice seller in Luxor, Egypt. A survey of traditional recipes show that spices are used extensively in the cuisine from cultures in tropical climes. (Photo: Tour d'Afrique / Flickr)
Another theory points to spicy foods' antifungal and antibacterial properties. In this light, humans have culturally and genetically evolved a preference for spicy foods because they protect us from microscopic assailants. When our taste buds encounter pungency, it's a signal to our brains that the food is cleaner.
A report published in the Quarterly Review of Biology looked at "[m]ore than 4,570 recipes from 93 cookbooks representing traditional, meat-based cuisines of 36 countries," as well as the antibacterial properties of the spices used. Their report found that where spoiled food is more of a concern, spices are more frequently used. The authors write:
Countries with hotter climates used spices more frequently than countries with cooler climates. Indeed, in hot countries nearly every meat-based recipe calls for at least one spice, and most include many spices, especially the potent spices, whereas in cooler countries substantial fractions of dishes are prepared without spices, or with just a few.
Beyond peppers, the research looked at less pungent preservatives. Garlic, onion, cumin, thyme and black pepper were all found to have antibacterial properties. Paul Sherman, an evolutionary biologist and one of the report's authors, noted that lab tests on 30 common spices have shown that "at least half of them kill or inhibit 75 [percent] of the bacteria they have been tested on."
Sherman also looked at vegetable recipes and found that spices are less common in them than meat dishes. This finding bolsters the theory. If spices were only about the taste, one would expect them to be found in equal proportions. It also deflates another theory that spices are preferred for their nutritional value, as vegetables are eaten in much greater quantities.
As Sherman puts it: "Everything we do with food — drying, cooking, smoking, salting, or adding spices — is an attempt to keep from being poisoned by our microscopic competitors. They're constantly mutating and evolving to stay ahead of us. One way we reduce food-borne illnesses is to add another spice to the recipe."
These two hypothesis may prove to line up with further research. It's possible our evolution led us to enjoy pungent food, while our natural thrill seeking behavior spurred us to cultivate peppers of unnatural heat.
Why we like what we like
A baby eats a bell pepper with his father. Preference for spicy foods, like all foods, is the result of a complex interplay of genes, culture, memory, and personality. (Photo: rabble / Flickr)
Of course, this article has ignored one crucial point: Not everybody likes the same level of heat and some people don't enjoy spicy foods at all. If people evolved a taste for spice, either for the thrill or its cleaning properties, why don't all people enjoy a nice chili eating contest?
As will surprise no one, the answer is that taste is complex. The number bumps of on your tongue, called papillae, can make you a "supertaster" or a "subtaster." Genes influence how your taste preceptors perceive flavors like bitterness. A bad childhood experience can turn you off to a food for life. And the interplay between culture and taste preference, as argued by John Hayes, is a chicken and egg problem.
"Is it that cultures use a ton of cilantro have a low proportion of people who find it soapy? Or, the other possibility is it just part of the cuisine so they just learn to deal with it," Hayes, associate professor of food science at Pennsylvania State University told U.S. News. "We don't know."
Hayes's research has even shown a link between taste and personality. In a 2013 survey, he found a positive correlation between sensation-seeking and reward-sensitive personality types and those who liked spicy foods. This supports Rozin, but the antibacterial hypothesis isn't out yet.
While not everybody likes spicy food, other popular flavors display bactericidal properties, too. Sherman's study showed that mint and sour foods, like lemons and limes, are also bacteria inhibitors.
And your brain may still register a food's clean burn, even if it isn't consciously palpable. When peppers were introduced to Europe, the Hungarians cultivated them into bell peppers. Sweeter and less pungent, the bell pepper nevertheless maintains antibacterial properties. And research out of the University of Southern California found that the carbon dioxide in fizzy drinks triggers a burning sensation in our pain sensors, the same response as horseradish albeit at a lower intensity. (Soda, it seems, hurts you in more ways than empty calories.)
Taken together, our understanding of taste would give any Martian anthropologist, and our human scientists, a lot to consider. Ultimately, how one species of primates came to mix pain, pleasure, and sustenance remains a tasty mystery.
Welcome to the world's newest motorsport: manned multicopter races that exceed speeds of 100 mph.
- Airspeeder is a company that aims to put on high-speed races featuring electric flying vehicles.
- The so-called Speeders are able to fly at speeds of up to 120 mph.
- The motorsport aims to help advance the electric vertical take-off and landing (eVTOL) sector, which could usher in the age of air taxis.
Airspeeder, the world's newest motorsport, is set to debut its first race in 2021.
What can you expect to see? Something like a mix between Red Bull's air racing and the pod-racing scenes from "Star Wars: The Phantom Menace" — manned electric cars flying close together in the desert at 120 mph, nose-diving off cliffs, and racing over lakes, all while hopefully avoiding collisions.
Airspeeder calls its vehicles flying electric cars, but it's probably easier to think of the wheelless multicopters as car-sized drones. Powered by electric batteries, the carbon-fiber craft use eight propellers to fly, and the tiltable motors are designed to allow pilots to navigate through the course's pylons at high speeds.
To prevent crashes, Airspeeder is working with the companies Acronis and Teknov8 to develop "high-speed collision avoidance" systems for its Speeders.
"As they compete, Speeders will utilise cutting-edge LiDAR and Machine Vision technology to ensure close but safe racing, with defined and digitally governed no-fly areas surrounding spectators and officials," Airspeeder wrote in a blog post.
Beyond motorsports, Airspeeder hopes to help advance the electric vertical take-off and landing (eVTOL) sector. This sector is where companies like Uber, Hyundai, and Airbus are working to develop air taxis, which could someday take the ridesharing industry into the skies. By 2040, the autonomous urban aircraft industry could be worth $1.5 trillion, according to a 2019 report from Morgan Stanley.
Still, many technical and regulatory hurdles remain. Matt Pearson, Airspeeder's founder and CEO, thinks the futuristic motorsport will help to not only speed up that process, but also pave the way for self-driving cars.
"Even with autonomous vehicles on the ground, it's a difficult thing to get right because computers have to make decisions very fast," Airspeeder's founder and CEO, Matt Pearson, told GQ." But in a racing environment, you have a pretty controlled course and you have the ability to make all the vehicles cooperate with each other. You have a whole load of vehicles talking to each other, so if there's an incident or a pilot slows down or there's a traffic jam on the course they're all aware of each other. This is something we think will revolutionise autonomous vehicles on the ground. It's technology that will make flying cars a reality in our cities in the future."
Airspeeder has yet to announce a date for the first race, but Pearson said he hopes to put on three races over the first season. The company is developing two courses: one in California's Mojave Desert, and one near Coober Pedy in South Australia.
The way you speak might reveal a lot about you, such as your willingness to engage in casual sex.
- A new study finds a deeper voice is associated with self-reported extraversion, dominance, and casual sex.
- It was the first study on the topic to objectively measure voice pitch.
- The authors suggest that hormones like testosterone might explain their findings.
We make snap decisions about other people based on information that we can gather quickly. One of the many ways that we do this is by making bold conclusions about other people's personalities based on their voices alone. Various studies demonstrate that people associate a deep voice with dominance, but those with higher pitched voices are perceived as nervous or neurotic. Popular culture seems to agree with and reinforce these stereotypes.
Are these perceptions accurate? Maybe. A new study by an international team of researchers with the goal of more accurately determining what our voices reveal about us has demonstrated that there is some connection between how we sound and who we think we are.
The voice-personality connection
Lead author Dr. Julia Stern of the University of Göttingen explained:
"Even if we just hear someone's voice without any visual clues — for instance on the phone — we know pretty soon whether we're talking to a man, a woman, a child, or an older person. We can pick up on whether the person sounds interested, friendly, sad, nervous, or whether they have an attractive voice. We also start to make assumptions about trust and dominance. The first step was to investigate whether voices are, indeed, related to people's personality."
The study included data from 2,000 people from four countries involved in eleven previous independent studies focused on other questions. Each of these studies involved some kind of self-reporting of personality traits and vocal recordings. The recordings were analyzed with Praat, software that determined the frequencies of the participants' speaking voices.
The study is the largest ever conducted on the topic and the first to use an objective measure of pitch rather than subjective rankings such as "high pitched" or "deep." Each participant's vocal pitch was then compared to the self-reported personality data they provided.
The findings associated self-reported levels of dominant tendencies, extroversion, and increased interest in and acceptance of sociosexuality (casual sex or sex outside of a relationship) with a lower pitched voice. This was true for men and women of any age. The findings were in line with the previous, less robust studies on the subject.
Other stereotypes, like if a higher pitched voice hints at neuroticism, openness to new experiences, or agreeableness, were impossible to determine with the data at hand.
Voice isn't everything
It should be remembered that the personality traits that this study associates with vocal pitch are self-reported, so there are some serious limitations. For instance, it is entirely possible that vocal pitch is associated with thinking you're extroverted when you actually aren't. Furthermore, all four countries in the study are WEIRD, so the findings probably cannot be universalized.
Additionally, there are plenty of examples of people for whom the voice-personality link doesn't apply. For example, Teddy Roosevelt, an extremely extroverted, dominating man, had a fairly high pitched voice.
The authors do speculate that there could be a connection between testosterone levels in men, their vocal pitch, and their perceived level of dominance that would be supported by previous studies. However, they have no hypothesis explaining why that same relationship exists for women.
The authors suggest that further studies in this area could focus on finding a possible physical connection between these traits and vocal pitch and to determine if they hold for traits which are not self-reported.
Who needs steroids when you have the placebo effect?
- A study suggests that the effectiveness of sports drinks may depend in part on their color.
- Runners who rinsed with a pink liquid ran better than those who consumed the same but colorless drink.
- Improvement in their performance is likely due to a placebo effect.
The "placebo effect" is real. It's the name for a strange phenomenon that most notably occurs during clinical trials. People who are given an inactive substance, like a sugar pill, often experience the same therapeutic benefit as those who are given actual medicine. It's not their imagination — it really happens. (Even better, recent research suggests that therapeutic benefits occur even when the person knows that they were given a placebo.)
Now, a new study from the University of Westminster (UOW) Centre for Nutraceuticals in London and published in Frontiers in Nutrition suggests that the placebo effect may explain yet another phenomenon: Athletic performance.
The research showed that treadmill runners who rinsed their mouths with a pink liquid increased their performance over runners who swished with exactly the same liquid but without the coloring. Why pink? The color is generally linked to sweetness, and the researchers wondered if that association would subconsciously trick the runners into an expectation of more carbohydrates and thus energy.
Author Sanjoy Deb explains:
"The influence of color on athletic performance has received interest previously, from its effect on a sportsperson's kit to its impact on testosterone and muscular power. Similarly, the role of color in gastronomy has received widespread interest, with research published on how visual cues or color can affect subsequent flavor perception when eating and drinking."
Running for science
Credit: Ryan De Hamer / Unsplash
For the study, the researchers recruited ten healthy adults — six men, four women. All were regular exercisers, with an average age of 30. The participants were told that they would be testing the relative benefits of two commercial sports drinks after watching a brief video explaining the value of such beverages. Previous research found that mid-exercise rinsing with such drinks can reduce the perceived intensity of exercise.
The drinks consisted of 0.12 grams of sucralose dissolved in 500 mL of plain water — an artificially sweetened rinse low in calories. The liquids contained no other additives common to sports drinks such as caffeine. The pink version had non-caloric coloring added but was otherwise identical.
After a 12-minute warmup phase of jogging followed by running, the athletes ran at a difficult pace for 30 minutes, rinsing with their drinks as they ran. Following a brief cool-down, they were interviewed to capture their impressions of the exercise session. (Each runner tested both drinks.)
The researchers found that when the volunteers used the pink rinse, they ran an average of 212 meters farther and 4.4 percent faster. They also enjoyed the exercise more.
Deb said, "The findings from our study combine the art of gastronomy with performance nutrition, as adding a pink colorant to an artificially sweetened solution not only enhanced the perception of sweetness, but also enhanced feelings of pleasure, self-selected running speed, and distance covered during a run."
The researchers also plan to dig deeper into the phenomenon by investigating the possibility that the pinkness of the beverage is somehow directly activating the brain's reward areas.