Learn about how rats might not have been all to blame for the bubonic plagues and why we’re more prone to mindlessly eat while we multitask.
Learn about how rats might not have been all to blame for the bubonic plagues and why we’re more prone to mindlessly eat while we multitask.
When It Comes to the Black Death, the Rats May Have Been Framed by Ashley Hamer
Multitasking might make you keep snacking even when you're full by Kelsey Donk
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Find episode transcript here: https://curiosity-daily-4e53644e.simplecast.com/episodes/why-multitasking-keeps-you-snacking
[MUSIC PLAYING] ASHLEY HAMER: Hi, you're about to get smarter in just a few minutes with Curiosity Daily from Curiosity.com. I'm Ashley Hamer.
NATALIA REAGAN: And I'm Natalia Reagan. Today, you'll learn about how rats might not have been all to blame for the Black Death and why we are more prone to mindlessly eating while we multitask.
ASHLEY HAMER: Let's satisfy some curiosity.
NATALIA REAGAN: Many deadly diseases throughout history have been traced to animals. H1N1 came from pigs. MERS came from camels, and COVID-19 may have come from bats. The same has been true of the plague. And we've thought for years that the Black Death of the 1300s was caused by rats, but a growing number of studies suggest the rats may have been framed.
(LOW-PITCHED VOICE) Dun, dun, dun, dun.
The Black Death, or bubonic plague, got its start in 1347 when 12 trading ships arrived at a Sicilian port via the Black Sea. Most of the sailors aboard were dead, and those who were alive were feverish and covered in boils. The ships were ordered out of the port, but it was too late. The illness spread quickly and killed 25 million people, more than a third of Europe's population at the time.
Back then, explanations ranged from the mundane to the supernatural, but by the 20th century, scientists understood that the plague is spread by a bacterium called Yersinia pestis. And it's most often contracted by the bite of a flea or louse. Those fleas typically come from rodents.
But it's not unheard of to have human ectoparasites, like lice or human fleas, travel from person to person. We've just never proven that a human has actually contracted plague from a human parasite. New studies suggest, however, that that's just what may have happened. This is because, during later plague epidemics actually caused by rats, there was a massive rodent die-off that caused these rat fleas to pick up and move to warm human bodies, but there's no record of that during the Black Death.
Critics also say the weather was all wrong for the number of rats you would have needed to have spread that kind of pandemic. And seeing as there aren't many rats in the archaeological record from that time, they're probably on to something. The most convincing evidence for the idea that it is spread by human ectoparasites was a study published by researchers at the University of Oslo in January 2018. The team created computer models to test three different transmission scenarios. In one, they modeled what the outbreak would have looked like if it was spread by rat fleas; in another, human fleas and lice; and in a third, air transmission from humans to humans.
The computer model showed that human-to-human transmission would have resulted in a gradually growing number of deaths that peaked later than what actually happened. Rat flea transmission would have peaked around the right time but would have caused more death than actually occurred. But human ectoparasite transmission nailed it for nearly all of the outbreaks. It best fit the timeline and death rate in the historical record. This has the potential to correct a centuries-old misconception.
But why does it matter these days? Well, because Yersinia pestis is still out there infecting people, so understanding the many ways that plague can spread can help prevent it when it returns. Let's just hope we can deal with this pandemic first. I mean, I don't know about you, Ashley, but every so often, you do see an article pop up about the Black Plague, showing up most recently in China, near Mongolia.
ASHLEY HAMER: If it was going to start spreading again any year, it would be 2020.
NATALIA REAGAN: [CHUCKLES]
ASHLEY HAMER: I just really want it to wait. [CHUCKLES]
NATALIA REAGAN: 2020 is like, hold my beer. [LAUGHS]
ASHLEY HAMER: Exactly.
NATALIA REAGAN: Let's get-- the bingo card is still being filled out.
ASHLEY HAMER: [LAUGHS]
NATALIA REAGAN: Oh, man. The Black Death, jeez. But those poor rats, man. Yeah, it's not fair.
ASHLEY HAMER: No.
NATALIA REAGAN: It's interesting what animals get blamed for being the scapegoat. Are goats ever the scapegoat?
ASHLEY HAMER: Oh, for the cubs losing, they are, yeah.
NATALIA REAGAN: Oh, really?
ASHLEY HAMER: I don't know enough about baseball, but I know there was like a cursed goat. Yeah, that was a scapegoat.
NATALIA REAGAN: You're kidding me. Hey.
ASHLEY HAMER: [SNICKERS]
NATALIA REAGAN: Ay, that's for you, Cody.
ASHLEY HAMER: If you're watching what you eat, you probably shouldn't watch anything else in the process. A new study shows that if you eat while you watch TV or play video games, you're less likely to realize whether you feel full even after you've stopped the activity. Researchers from the University of Sussex have found that when your senses are engaged in an all-consuming task, your mind may filter out sensory cues that it considers less important. And sometimes, those cues involve how full you feel. Here's how they figured this out.
The team recruited 120 women and had them play a computer game where they had to find a particular letter on the screen. Half of the volunteers got the easy version of the game, while the other half got a version that was more mentally taxing. While they played, all of the women drank a smoothie. Unbeknownst to them, some of the smoothies contained about 300 calories, and some contained less than 100.
Afterward, the researchers presented the participants with a platter of potato chips and invited them to eat as many as they liked. How many of those chips they ate depended on how demanding the game was. The participants who had played the difficult game ate the same number of chips regardless of how filling their smoothie had been. Their attention was elsewhere while they were drinking, so they didn't notice that they were full when the chips arrived. But the people who ate their chips after doing the less engaging task were able to adjust how many they ate. The people in this group ate almost half as many chips after the high-calorie drink as after the low-calorie drink.
It's common knowledge that you shouldn't eat dinner in front of the TV or have lunch at your desk at work for so many reasons. And we've all had the experience where you just start eating a bowl of popcorn while watching a movie and look down a few minutes later to find the Bowl empty. But this is the first time a study has really nailed down why this happens. The researchers concluded that when your senses are fully engaged, your brain filters out information about fullness.
If you're totally consumed by a movie, a game, a conversation, or even a crossword puzzle, you may not notice that you're full. So the next time you sit down to a meal or kick back with a snack, turn off your devices and try to focus on eating. You might enjoy it a lot more. And snack a little less.
NATALIA REAGAN: This one hits home. [CHUCKLES]
ASHLEY HAMER: Oh, yes. Me, too.
NATALIA REAGAN: No, just I think of movie theaters and buying that huge tub of popcorn and somehow going to the movie theater, having eaten lunch or dinner, and still managing to eat a tub of popcorn.
ASHLEY HAMER: Totally. It's like you have an extra popcorn stomach. Like, there's just extra room made for it.
[LAUGHTER]
NATALIA REAGAN: I wonder if we'd evolve that over time, like an extra stomach.
ASHLEY HAMER: Like cows? Yeah. [CHUCKLES]
NATALIA REAGAN: Yeah, exactly. Let me ruminate on that.
ASHLEY HAMER: [GIGGLES]
NATALIA REAGAN: Oh, I'm sorry. That was awful.
ASHLEY HAMER: That was wonderful.
NATALIA REAGAN: Let's recap today's takeaways.
ASHLEY HAMER: Well, for one thing, we learned that we may have been blaming the wrong pest for the Black Plague. Computer models reveal that it might have been human fleas who were the real spreaders of the bubonic plague because humans are nasty, and we can totally spread stuff to each other, which is why you should wash your hands and wear a mask and socially distance right now.
NATALIA REAGAN: Absolutely. I think this is a totally radical result to a study. And I want to say a good congrats to the rats--
ASHLEY HAMER: [LAUGHS]
NATALIA REAGAN: --out there that are now getting vindicated. I feel for you. We also learned that we are more prone to mindlessly eat when we're multitasking since our brain is so distracted to notice we're actually full.
ASHLEY HAMER: I grew up eating around the dinner table with my family, and we never would turn on the TV. But as I got older, man, nothing like cooking a meal and sitting down in front of Netflix. I'm so guilty of it.
NATALIA REAGAN: Oh, absolutely. It's a ritual. If I'm going to get takeout or something like that and splurge, of course, I'll throw in a movie. And all of a sudden, everything's gone. And that's the sad thing. You almost don't even remember what you ate. There's not even a chance to really savor it.
ASHLEY HAMER: Right. Absolutely. Whether you want to eat less or not, just the ability to enjoy your food is really important because food is amazing. Food is one of--
NATALIA REAGAN: Oh.
ASHLEY HAMER: --the greatest things in life. [CHUCKLES]
NATALIA REAGAN: Oh gosh, yeah. That's one of my biggest joys in life is I'm looking forward to the next meal. I wonder how COVID has affected how we're eating and where we're eating. I live in New York City. There are restaurants that have outdoor seating, and you can have that sort of dining experience. But oftentimes, now we're dining at home all the time and doing it in front of the television. You have to really set aside that time to savor the food, to connect with one another because the whole idea of even breaking bread with others is not only-- it's a bonding experience as well as a bonding experience with your actual meal.
ASHLEY HAMER: Right, yeah. I mean, this goes way back in human history. It's important to us.
NATALIA REAGAN: Yeah. I'm sad we can't go get a bite to eat right now, Ashley, because we're in two different. [CHUCKLES]
ASHLEY HAMER: Yes, that's so sad.
[LAUGHTER]
I remember the last food we ate together was-- we had some good Mexican food.
NATALIA REAGAN: We did. That was in Chicago.
ASHLEY HAMER: Yeah.
NATALIA REAGAN: Yeah.
ASHLEY HAMER: Yeah.
NATALIA REAGAN: Maybe we can Skype meal. Would that be--
ASHLEY HAMER: Yeah!
NATALIA REAGAN: --too much multi-- [GIGGLES]
ASHLEY HAMER: I know. It might be multitasking.
[LAUGHTER]
NATALIA REAGAN: Wait a minute. Didn't you just have a loaf of bread sitting next to you, Ashley? Where did it go?
ASHLEY HAMER: [LAUGHS] I could totally do that.
NATALIA REAGAN: Yeah, I heard you're good at the sourdough.
ASHLEY HAMER: I'm also good at putting away the sourdough.
[LAUGHTER]
NATALIA REAGAN: Well, it's got to go somewhere, so waste not whatnot.
ASHLEY HAMER: Absolutely.
NATALIA REAGAN: Today's stories were written by Ashley Hamer and Kelsey Donk and edited by Ashley Hamer, who's the managing editor for Curiosity Daily.
ASHLEY HAMER: Scriptwriting was by Natalia Reagan and Sonja Hodgen. Today's episode was edited by Natalia Reagan. And our producer is Cody Gough.
NATALIA REAGAN: Join us again tomorrow to learn something new in just a few minutes.
ASHLEY HAMER: And until then, stay curious.
[MUSIC PLAYING]