Science Friday - How Trivia Experts Recall Facts | One Ant Species Sent Ripples Through A Food Web

Episode Date: February 27, 2024

How can some people recall random facts so easily? It may have to do with what else they remember about the moment they learned the information. Also, in Kenya, an invading ant species pushed out ants that protected acacia trees. That had cascading effects for elephants, zebras, lions, and buffalo.A ‘Jeopardy!’ Winner Studied How Trivia Experts Recall FactsWhen contestants play “Jeopardy!,” it can be amazing to see how quickly they seem to recall even the most random, obscure facts. One multi-time “Jeopardy!” contestant, Dr. Monica Thieu, noticed something interesting about the way that she and her fellow contestants were recalling tidbits of information. They weren’t just remembering the facts, but also the context of how they learned them: where they were, what they read, who they were with. Hypothesizing that for trivia superstars, information was strongly tied to the experience of learning it, she put that anecdotal evidence to the test. The results of her research were recently published in the journal Psychonomic Bulletin & Review.SciFri producer Kathleen Davis talks with Dr. Thieu, a psychology researcher at Emory University, and Dr. Mariam Aly, assistant professor of psychology at Columbia University, and a co-author of the new study. They discuss the psychology of trivia, how to get better at it, and why some people seem to be much more adept at recalling fun trivia facts than others.See if you can beat a "Jeopardy!" champ on our website!How One Invading Ant Species Sent Ripples Through A Food WebWhen people talk about the interconnectedness of nature, the usual example involves a little fish that eats a bug, a bigger fish that eats the little fish, and an even bigger fish at the top of the chain. But in reality, the interconnected relationships in an ecosystem can be a lot more complicated. That was certainly the case in a recent study, published in the journal Science, which describes how the arrival of an invasive ant species changed the number of zebras that get eaten by lions on the Kenyan savannah.The unwelcome ant is known as the big-headed ant. It’s on a list of top 100 invasive species around the world. When it arrived on the African savannah, the ant newcomer muscled out a native ant species known as the acacia ant—which, though tiny, was able to help defend acacia trees from being grazed upon by elephants (picture getting a trunkful of angry ants while snacking).With the trees undefended, hungry elephants feasted, resulting in fewer trees on the savannah and more open space. That made the hunting environment less favorable to stealthy lions, and more favorable to fleet-footed zebras. But to the surprise of the researchers involved with the study, that didn’t mean hungrier lions. Instead, the lions shifted their hunting from targeting zebras to targeting buffalo instead.Dr. Jacob Goheen and Douglas Kamaru of the University of Wyoming join guest host Sophie Bushwick to describe their research, and how a small ant can have a big effect on an ecosystem.Transcripts for each segment will be available after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

How can a tiny ant change how lions hunt? There's a hint. It involves trees and elephants. So you've got these tiny three milligram ants that are defending trees against three billion milligram elephants. It's Tuesday, February 27th, and you're listening to Science Friday. I'm SciFri producer Charles Bergquist. Coming up, we'll talk with researchers studying the predator prey dynamics of the African savannah about the chain of effects one invasive ant species.

had on the ecosystem. But first, Kathleen Davis talks with two researchers investigating the psychology of trivia, how to get better at it, and why some people seem to be much more adept at recalling fun trivia facts than others. Here's Kathleen. I love doing trivia. Every couple of weeks, I go to my local dive bar for trivia night. I'm also an avid Jeopardy Watcher. But despite all this, I'm still not very good. But rather than give up a my dream of being a top-tier trivia player. This got me thinking, can I actually get better at trivia? And why are some people better at it than others? A new study in the journal Psychonomic Bulletin and Review looked at exactly this. And here to break down the psychology of trivia are

two co-authors of that paper, Dr. Monica 2, psychology researcher at Emory University, and a Jeopardy winner. She's based in Atlanta, Georgia, and Dr. Mariam Alley, assistant professor of psychology at Columbia University in New York. Welcome both of you to Science Friday. It's amazing to be here. Thank you. Yeah, thanks so much for having us. I'm really excited. Yeah, so am I. So Monica, tell me a little bit about where the idea for this study came from. I mean, was it from your time on Jeopardy? Yeah, I mean, to be fully frank, since I first was on Jeopardy as a senior in high school, when I went to college and I majored in psychology, I was like, no, one day I'm going to have a research study where we can call Ken Jennings and ask him to come in and get his brain scan,

which we didn't skin anyone's brains for this study, so it still do it. But I have been curious for a long time about how trivia experts' memory, I suppose, including mine, is maybe different than other people's because I've always known other people in my classes and my grad programs who are so smart. And yet they all were like, Monica, why do you know? know all this random stuff. And so it really wasn't until I was in grad school where I felt like I had enough of the science idea to actually do a research study about it. So you didn't get to scan Ken Jennings's brain, but did you talk to other Jeopardy contestants about this? Yeah. So in 2019,

I was invited back to do the Jeopardy All-Star Games. And while it was there, I was meeting other Jeopardy champions who were so great and so smart and so knowledgeable. And, as we were talking about people's, you know, experience of knowing and remembering trivia, something that I realized that we seem to have in common was that all the experts that I talked to seemed to have a really good memory for the episodic details of when they learned to trivia facts. So like, where were you? What textbook? What class? Like, where did you sit? What trip did you go on where you saw this in a museum? Like, all of that side memory that is about learning the fact but not necessarily specifically the information itself.

Okay, very interesting. So how did you actually test this idea, Monica? So when Miriam and I were designing this research study, we knew that we had to try to teach people new facts in the lab. Because if you're trying to recruit some trivia experts and some trivia non-experts to do a study, obviously the big issue is that half of your participants, oh, what do you know, a bunch of stuff?

And so then we're not testing their memory for learning new things. we're only testing their memory for stuff they already know. So what I did with Lauren, our third co-author, was we basically like literally went to the library and checked out reference books and like went to the Met, went to Encyclopedia Britannica.com and spent so much time on there collecting lots of obscure facts to put together these little quote unquote science and history museums. So what these museums really are is it's an online task where on each exhibit page, You would see a little picture of an exhibit item, so maybe like a particular musical instrument from history,

and you'd also see a little paragraph place card giving you some information about that musical instrument, and you'd be read the fact on the place card by the narrator. So what we had people do is we had them go through these museums one exhibit at a time. Then after they went through these museums, we tested their memory for three different things. So first we tested their memory for the trivia facts that they would have learned from the place cards. Then we tested their memory for which exhibit pictures they saw. So let's say you saw a picture of a Hardinger fiddle, which in this case is like a Norwegian violin-like instrument. They used it in the Lord of the Rings, the two towers for the Rohan theme.

It's great. But let's say we show you two different pictures of two Hardinger fiddles. One is the one you saw before, and one is a slightly different picture of a different fiddle. But you can't use your memory to say, one is a fiddle and one is not, you have to remember exactly which one you saw. So after we tested people's memory for the facts they saw and the exhibit pictures, finally, we tested their memory for which museum they saw that picture in. Because we showed people these exhibits in two different, quote unquote, museums. One was called the Amber Archives where everything was like orange themed. And one was called the Cobalt Collections where everything was blue themed.

So then when we analyzed the data, we looked at A, how was people's memory for the facts that they learned in the study? And B, does memory for the picture that you saw in the exhibit and which museum you saw it in seem to correlate with your memory for the fact itself? Okay, super fascinating. So, Mariam, when you took a look at all this data, what did you find? So what we found is that trivia experts were better at learning brand new novel facts in our experiment. So these are facts they had only seen before in our study and they were better at acquiring these new facts. But they didn't have better memory overall. So if we just asked them to indicate which of the two photographs they saw in the exhibit, they weren't better at that than people who weren't experts. So their memory wasn't better across the board, but they seemed to be uniquely good at learning new facts.

And the critical thing that we found was that in trivia experts, but not non-experts, when they remembered a new fact, they were also more likely to remember multiple features about how they learned it. So they remembered the details of the museum exhibit, like whether it was the Amber Archives or the Cobalt Collections, and the specific photo that was paired with that fact. So it really nicely dovetails with the anecdotal reports from experts that when they recall a fact, they remember details about how and where they learned it. Okay, super interesting. So, Mariam, I mean, why do some people remember better than others? Do we know? Like, is that information stored in maybe different parts of the brain? That's a really good question. In this

particular study, we don't know whether trivia experts are better able to bind these unique information about the fact and the episode because of something different about how they're paying attention, if it's something different about how their memory systems work, or if it's something else altogether. We do know that they don't seem to be trying to do this intentionally, so it doesn't seem to be a strategy that trivia experts have, that non-experts don't have, but we don't know yet whether it's something related to how they pay attention during the learning experience. Do they, you know, do they attend more broadly, whereas non-experts might attend more narrowly? Or is it something related to how their memory systems work? So is it just that their episodic

memory system and their kind of fact memory systems are more tightly coupled than those of non-experts? Okay. So, I mean, can I take this information and apply it to my own learning? Like, can I train myself to become the winner of my local bars trivia, Miriam? I wish I could answer that. I can speculate. Based on our results, we don't know whether this is going to be trainable. So we'd like to think that given that trivia experts have these super bound memories between what they learned and how they learned it, that maybe if we could get non-experts to try to bind those pieces of information together, maybe they'd become more like the experts. And to answer that question, we'd really have to do another study where we try to train people

to show these memory signatures of experts by binding together what they learned and how they learned it. So can you kind of walk me through? There's this concept of the memory palace. Can you kind of walk me through what this is and what it means? Yeah. So the memory palace is a related but really relevant concept. So when we think about a memory palace, for example, if I need to memorize, and for reference, I'm way too lazy to learn how to do this stuff. But if I need to memorize, let's say I shuffle a deck of cards and I lay out all the shuffled cards and I need to remember the order of each of the 52 cards only by looking at the deck for like 15 or 20 seconds. What I might do is I might prepare for each of the 52 cards, let's say the queen of spades

versus the three of diamonds. I might prepare for each of those a particular really vivid image that I then place in a memory representation of a physical location that I know really well. So let's say like my apartment building or my office. And then if I need to remember a list of arbitrary things like the cards in the deck, I can place each of those sort of card like mental images. So, for example, for the three of clubs, maybe it's like Jerry Tidefeld or something. I can place each of those people places ideas into my memory palace, in this case, my mental image of my apartment. And as I walk around and I go through the list, it'll help me remember the information in that list.

better because people's episodic memory, their memory for places, experiences, and perceptual information. So what we can see here, taste, smell, et cetera. It's really good. And so memorizing lists is not something that people are generally as good at. So the memory palace is believed to work because it allows us to leverage the episodic memory system for remembering places and experience and especially navigating through places and seeing things. that it allows us to use that system to help us remember lists of things. The way we think this relates to the memory that we study is that we don't actually think that trivia experts are using a memory palace, but the memory palace shows us that when we use

episodic memory, it can help us remember some non-episodic memory or fact information better, and that maybe trivia experts are doing something sort of in the other direction, where because their episodic memory and their fact memory are naturally talking to each other more, that that helps them remember the facts better. Thank you both so much for joining me, Dr. Monica Tew, psychology researcher at Emory University in Atlanta, Georgia. And Dr. Mariam Alley, assistant professor of psychology at Columbia University in New York. Thank you. It's been fun. Thank you so much. It's been a pleasure.

When people talk about the interconnectedness of nature, the basic example you should goes something like, the little fish eats the bug, the big fish eats the little fish, and then an even bigger fish eats that. But in reality, the relationships can be a lot more complicated. Take the example of a recent report in the journal of science, which describes how the arrival of an invasive ant species in Africa changed the number of zebras that get eaten by lions. Joining me now to help connect those dots are two of the researchers on that project. Jacob Gohien is a professor and Douglas Camaro is a graduate student, both in the Department of Zoology and Physiology at the University of Wyoming in Laramie, Wyoming. Welcome to Science Friday.

Thanks, Sophie. Good to be here. This is a bit of a twisted path, so let's step through it point by point. First, to set the scene, where were you studying? So this research occurred at Old Pedyta Conservancy, which is right on the equator in central Kenya. and it's about a 250 square kilometer property. It's managed jointly for wildlife conservation and also cattle ranching. And can you describe the landscape there for us? I'd call it a classic African savannah.

So you've got too many trees to call it a grassland, and you've got too many grasses to call it a forest. So it's kind of between those two extremes. and both of those plant forms kind of co-occur, but neither really out-competes or dominates the other. And so that's the situation, and then these invasive ants, they arrive on the scene. So who are these guys?

This is the big-headed ant, the dull megasepal. And we're really not sure about its origins. It likely was introduced in bushels of produce imported from somewhere in the Indian Ocean, perhaps Mauritius. These are roughly one milligram ants, and they're labeled as one of the globe's top 100 invaders. And when they invade, what happens? In general, not much. But in this instance, the trees that I was just describing earlier are what we would call

mermaica fights. They're ant plants. They defend themselves with these tiny little bodyguards. guards. These are called acacia ants or sometimes cocktail ants. They're tiny, but they're three times the size of a big-headed ant. So they're about three milligrams. And believe it or not, they defend trees from the world's largest extant land mammal, that being the African elephant or the savanna elephant. So you've got these tiny three milligram ants that are defending trees against three billion milligram elephants. Hang on. How are ants defending trees against

elephants? So that's a great question. If you think about elephants, they're unique in a number of things, one of which is their nostrils are about six or eight feet from their mouths. So their nostrils are on the tips of their trunks. And so when they're feeding on a tree, they've got to stick that trunk into a bunch of foliage and then grab a trunk full of loose. And then grab a trunk full of leaves and pull, and that whole process takes about three seconds before the elephant is putting those leaves into its mouth. And in that time, you've got lots of these acacia ants that are swarming up into the nostrils of elephants. Ouch. Yeah, ouch. And because of that trunk, it kind of exposes elephants to this unusual defense by the tree. Things like giraffes

will just use their tongues to swipe ants away from their eyes and nostrils. Things like black rhinos will just plug up their nostrils and eat, but the system is kind of rigged against elephants because of that trunk. And so to get at your earlier question, what the big-headed ants do is they form these super colonies of tens to hundreds of thousands of individuals. And unlike the acacia ants, they don't defend trees. They don't live on trees. They live in cracks and crevices in the soil.

And just by virtue of their numbers, they can overwhelm and just clobber the native acacia ants and render those trees defenseless against elephants. So essentially what happens is the big-headed ants come in. They destroy the defenders of the trees, these larger ants that have been protecting the trees from elephants, and then the elephants reduce the tree cover. Is that right? Yep, you got it, absolutely. So when you lose that tree cover, what happens to the other animals?

I mean, the ones that we addressed in this study were lions and their primary prey, those being plain zebra. And zebra require kind of big open expanses to detect lions. They want to see lions and then just run away from them. So in areas that are open where tree cover has been reduced, zebra can more effectively avoid lions. On the flip side of that, lions like areas that are bushy. So they like these trees, they like to hide behind them and use them as stocking cover. So you can imagine that when you go from, you know, a pretty dense savanna with lots of trees to one that is suddenly now more open, the lions are exposed and they can't ambush zebra as effectively as they once did.

Okay, so I think I understand the theory here, but Douglas, could you tell us a little about how you did go about proving this in practice? Yeah, thanks, Sophie. What we did, actually, we used a combination of methods. You know, we assessed a tree cover, like to see how comparing areas that are invaded by the big-headed ants and the areas that are not invaded. And what we notice or what we realize is that, you know, in invaded areas, we had about five to seven types. a higher disability or low tree covers compared to areas that we did have big-headed ants. We also colored or fitted GPS collars on lions to be able to tell where they are going in real time or where they're moving.

Oh, wow. Wait. What was, sorry, I have to interrupt. What was it like to put a tracking collar on a lion? Quite some work. Yeah, that involves a lot of logistics. Because we did that in collaboration of partnership with Kenyon. a wildlife service. So there's a lot of moving parts that we had to put together. With lions,

you have to dart them using a dart gun, like kind of make them sleep. And then you feed the GPS. And also it's a lot of work like going out in early in the morning looking for them, you know, see where they're occupying within the conservancy or vegetum. And also we use the GPS quarters to see where they're killing. Once the lion, we get it, the lion is staying in one place for long. then we go there and then we assess what actually. The question is what the lion is doing there. So sometimes you go there, you find them with a kill and you are able to identify the kill. And also sometimes you could go and find some little carbs.

You know, because lions, one day, lions, they have little cats. They tend to stay in one place for quite a while. We also did count animals like zebras within the conservancy to be able to determine the identities and so on. Okay. And you mentioned that so the lions aren't able to prey on the zebras as easily when they're in these areas where the big-headed ants have moved in. So did you find that the lions were going hungry or did they end up eating something else? Our hypothesis was what was if the lions are not able to eat zebras, which is their primary prey, then they'll go hungry. And then after they go hungry, then we expect their population to decry.

But that's not what we saw after within our analysis. So we were a little bit surprised. And then after analyzing some more data, that's when we realized that lion actually shifted their diet to eating more buffaloes. So the lions actually were able to switch their diet and, you know, killing more buffaloes. Although it's actually difficult to kill buffaloes because it takes up to five to ten adult lions to bring down a buffalo. Because the buffaloes are aggressive and they tend to kind of fight back compared to zebras. And it takes like, let's say, two to three other trials to bring down a zebra.

Wow. So I guess that's good news for the zebras. But Jake, can you tell us what's going to happen to them? Is their population just going to get really big in these treeless landscapes? That's a good question. We think that probably is not likely in that zebra numbers are controlled by grass. So they're controlled by their food supply, which is in turn controlled by rainfalls. Do they seem to vary independently of what the lions are doing? On the other hand, it is possible that this prey switching from zebra to buffalo that Douglas just described could reduce the number of buffalo on this property.

And is the cascade of effects going to keep going beyond even reducing buffalo? Like, do fewer zebra kills also affect the vultures or some other scavengers? Yeah, that's another great question. We really don't know. Whenever there are big species invasions, like with this big-headed ant, there are winners and losers, and sometimes those take a while to reveal themselves. So I could imagine something like that happening. The thing that I think is on both Douglas's and my radar is that this particular tree, this Mermeca fight, is a key food for globally endangered black rhinos. So that I think is the next thing that we likely would look at. Where do you go from here? So what's next for your research in this area? The next things we're really interested in looking at is whether the removal or the eradication of big-headed ants will revert those invaded areas back to something that resembles their kind of natural or pristine state. It's possible that we remove the invasive ant and the acacia ants recolonize.

They defend trees and we get something resembling the savannah prior to that big-headed ant invasion. It's also possible that we remove the big-headed ants and then nothing happens, in which case it would say that it's more difficult to restore this ecosystem than we might have thought originally. The second thing, and Douglas mentioned this in one of his earlier answers, is that it takes three to four times the number of lions to bring down a buffalo than it does a zebra. And frequently in the Serengeti greater ecosystem to the south, male lions are involved in hunting buffalo, which is pretty unusual. They typically are not involved in hunting other prey.

So we're actually interested in whether this big-headed ant invasion is causing changes to the social structure of lion prides and different hunting groups of lions. Thank you both so much for coming to tell us about how these teeny tiny ants have had such a massive effect. Absolutely. Thanks a bunch for your interest. Jacob Goheen is a professor and Douglas Camaro is a graduate student, both at the Department of Zoology and Physiology at the University of Wyoming in London. Laramie, Wyoming. That's it for today. Lots of folks help make the show happen this week, including Willis Samirs, Danielle Johnson, Beth Rami, Nahima Ahmed, and many more. Next time, we'll dive into the sensitive science of shark smell. Probably best not to boop that's new. I'm Charles Berkwist. Thanks for listening. We'll see you soon.