Hiring discrimination laid bare by mountain of data

Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, the ongoing problem of hiring discrimination…

Host: Nick Howe

And, oh man, what was it again? Oh yeah, making fruit flies forgetful. I’m Nick Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

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Interviewer: Nick Howe

I think we can all mostly agree that looking for a job is pretty stressful. But for certain groups of people, it can also be an unfortunate reminder of the bias and prejudice that exists in the world.

Interviewee: Valentina Di Stasio

Discrimination is enduring and it’s pervasive.

Interviewer: Nick Howe

This is Valentina Di Stasio, a sociologist who has worked on the GEMM Project, a project that aims to identify discrimination across Europe.

Interviewee: Valentina Di Stasio

The research on discrimination goes back to the 60s and it has demonstrated over and over again that discrimination is pervasive. With regards to ethnic and racial discrimination, the general result is that there is discrimination in most of the contexts and also discrimination is enduring. It has not diminished over time and we have made comparisons of experiments that have been conducted in different decades and the alarming result is that there is no decrease.

Interviewer: Nick Howe

Research about discrimination has, up until now, largely relied on correspondence studies. These involve sending multiple fictional CVs to a job opening, all identical apart from one characteristic – something like ethnicity or gender. Here’s Valentina again.

Interviewee: Valentina Di Stasio

These allow us to then compare the invitations that they receive, the invitations to a job interview, for example, and then to basically understand whether there has been discrimination. These types of experiments are typically considered the gold standard in discrimination research, however this research stops at the moment of application, so we send the application and then we have no control over what happens next.

Interviewer: Nick Howe

Also, in these studies, you can’t send too many CVs or you risk interfering with real jobseekers. Scientists needed another approach and, this week in Nature, Dominik Hangartner and his colleagues have been pioneering a new method using large datasets from employment websites in Switzerland. Here’s Dominik.

Interviewee: Dominik Hangartner

So, what we’ve done in collaboration with the Swiss Ministry is that we track how recruiters on the website search which profiles of potential candidates they look at, how long they look at these profiles and who is contacted for a job interview.

Interviewer: Nick Howe

The advantage of this is that you have real-world data and a whole lot of it. Dominik and his team were able to leverage data from the Swiss Public Employment Service to get information about millions of jobseekers and hundreds of thousands of job searches by tens of thousands of recruiters. That’s a lot of big numbers. Now, things like nationality and ethnicity are not always included in job applications in Switzerland. But Dominik and his team could still make certain inferences in the same way it appears that recruiters do. In particular, they looked at three factors to make inferences about candidates – their name, their spoken languages and whether they had Swiss citizenship. In fact, Dominik was able to group jobseekers into ethnicities from nine different regions, with people who have a Swiss name, speak a Swiss language and have Swiss citizenship as a reference.

Interviewee: Dominik Hangartner

What we find is that if we compare these several applicants that appear in the same search, that people from minority ethnic and immigrant backgrounds face 4 to almost 20% lower contact rates compared to ‘native Swiss citizens’, that is people with a Swiss name who speak one of the Swiss languages and who have Swiss citizenship.

Interviewer: Nick Howe

Contact rate is a measure of how often a recruiter clicks on a jobseeker’s application to receive their contact details, and that click is directly linked to a jobseeker’s chances of being employed in the next few months. And within that 4-20% range, there appears to be a pattern.

Interviewee: Dominik Hangartner

What we found is a pattern that fits theories of so-called ethnic hierarchies, meaning that immigrant and minority ethnic groups who are more distant, be that in terms of culture or language or skin tone, face more discrimination than those groups that are more similar. In the Swiss context that we focus on, that means that we find almost hiring discrimination for immigrant jobseekers from Italy or Spain, but a lot of hiring discrimination for immigrant jobseekers from sub-Saharan Africa or Asian countries.

Interviewer: Nick Howe

So, whilst immigrant jobseekers from western Europe may only face a small penalty in the eyes of recruiters – around 4% – people from sub-Saharan Africa and Asia face around a 20% penalty. These are from otherwise comparable CVs, what’s known as ‘observably similar applicants’. For Valentina Di Stasio, who you heard from earlier and who wasn’t associated with this study, these results aren’t particularly surprising.

Interviewee: Valentina Di Stasio

The findings from this study are quite consistent with a broader literature on discrimination.

Interviewer: Nick Howe

Dominik also used this approach to investigate gender discrimination, and it seems that this picture is a little bit more nuanced. Here’s Dominik.

Interviewee: Dominik Hangartner

Across the 70 million decisions to contact or not contact a woman or man applicant, on average we don’t see any evidence of discrimination. So, that was a bit of a surprise. But then we started to unpack it because we have so much data, and so what we find is that this average null result of no discrimination masks a lot of variation across occupation, and the pattern that we documented is very striking in the following sense. Women who apply in typically male-dominated jobs, say construction or forestry, face a lot of discrimination and much lower contact rates compared to equally qualified men. However, we also see exactly the symmetric or similar pattern for men applicants equally qualified who apply in women-dominated professions, for example in the care and the health sector.

Interviewer: Nick Howe

Dominik’s work only gives an indication of how often people are contacted for an interview. It doesn’t say anything about pay gaps or other aspects of the labour market that have been previously linked to gender-based discrimination. But to Valentina, this approach could still be very powerful to dig deeper into how different forms of discrimination interact.

Interviewee: Valentina Di Stasio

What I see as a potential of this study is that they could try to understand the role of ethnicity and gender in combination, so in interaction with one another, and this would be very interesting because we could study whether the same gender pattern can also be observed with members of disadvantaged groups, so ethnic minorities. Do we see the same pattern?

Interviewer: Nick Howe

To tackle discrimination there’s patently a lot to be done. Dominik and his colleagues’ data mostly shows associations, but it also lays the foundations for others to assess recruitment websites and perhaps try out different ways to reduce and hopefully eliminate the observed discrimination. What can we do, is what Dominik is focusing on next.

Interviewee: Dominik Hangartner

That’s one of the most important questions for me and all of my colleagues who work in this area to focus on. I think it’s important to document discrimination, it’s important to have evidence about the potential drivers of this discrimination because that has some consequences of how we’re going to tackle it. But at least my colleagues and I think that over the next months we are well advised to spend most of our time and effort and think about how we can overcome discrimination.

Interviewer: Nick Howe

That was Dominik Hangartner from the London School of Economics in the UK and ETH Zurich in Switzerland. You also heard from Valentina Di Stasio from Utrecht University in the Netherlands. We’ll put a link to Dominik’s paper in the show notes.

Host: Benjamin Thompson

Now, it’s time for Coronapod where we discuss the latest coronavirus news. Noah Baker’s here, of course, but returning to Coronapod after several months away is Nidhi Subbaraman, a senior reporter here at Nature, based in Washington DC. Hello to you both.

Nidhi Subbaraman

Hello.

Noah Baker

Hi there, Ben.

Host: Benjamin Thompson

We’re recording this on Tuesday but when listeners will be hearing this, it will of course be Wednesday and Joe Biden’s inauguration day, and obviously we hope that goes uneventfully of course. It’s the start of another chapter in US politics but potentially it’s also the start of another chapter in the coronavirus response and, Nidhi, that’s what you’re here to talk about today. Maybe before we get into what that response is, let’s perhaps get a snapshot of where we are in terms of the pandemic in the US right now.

Nidhi Subbaraman

We are almost a year into the first reports of the coronavirus being present in the US and we are unfortunately reaching the grim milestone of 400,000 deaths. The top issue that is on everybody’s minds is the vaccine rollout. The US is one of the nations that has a good supply of the Pfizer and Moderna vaccines, but there have been all kinds of hitches and trouble with shots getting into peoples’ arms. Of course, the old troubles of data access, of information, of resources as hospitals filled up again this past couple of weeks, have been going on, but now that there’s sort of that silver lining on the horizon, people are sort of waiting to see when the gears will change.

Noah Baker

There’s endless challenges associated with things like rolling out a vaccine in a pandemic, but the States is also in this kind of very peculiar position of also changing administrations, which is what’s happening with the inauguration, and that change is fraught with a huge amount of political tension, and that change represents two very distinct approaches towards public health and towards how to manage the pandemic, so it’s an awful lot of stuff to happen all at once. I kind of want to know what it feels like in DC right now.

Nidhi Subbaraman

Yeah, it’s so strange to be stuck in the bubble at home when all of this is going on just a couple of miles away. I was out when Trump was inaugurated, in the crowds with people waving flags as he spoke on the podium, and now it sounds like that entire area is going to be marked with row after row of little flags, which is both an indication of the state of the pandemic that we’re in and also the additional measures around security and violence that

erupted at the Capitol on 6 January and the reality of the insurgence that we witnessed earlier this year. The president-elect and vice-president are due to arrive, I think, today evening, and the first thing that they’re going to do as far as kicking off inauguration activities is a memorial at the Lincoln Memorial where they’ll have 400 lights around the reflecting pool to mark the 400,000 deaths that the US is approaching, so a sombre start to a major shift.

Host: Benjamin Thompson

And what do we think this shift is going to look like? Of course, the new president, President Biden, really started talking about the coronavirus a very, very long time ago. This response isn’t something that’s been thrown together in the past few weeks. How has what he said evolved, do you think?

Nidhi Subbaraman

Yeah, so among the first announcements almost after the election results were made clear and were called was the announcement of a White House coronavirus taskforce that was stacked with luminaries and respected experts who’ve worked on pandemics in the past. So, right off the bat, we have experts front and centre. And then we’ve seen statements about mask mandates. We’ve seen last week, David Kessler, who’s a huge figure in health policy and public health circles, named to head up Operation Warp Speed, which is the US vaccination programme. And then there was a detailed vaccine strategy that the Biden administration announced on 15 January that talks through all kinds of logistics. So, both in terms of the people in the right positions and the start of a plan beginning to take shape, it seems like the pieces are beginning to be in place.

Noah Baker

It’s striking to hear almost everything that you’ve just said. The stacking of experts behind this, a mandate to wear masks. It feels like, in many ways, the Trump administration’s response to the pandemic has been characterised somewhat by side-lining experts. The CDC was side-lined, the WHO have been side-lined. Aside from perhaps Anthony Fauci, there were very few scientist voices involved in the response, and mask wearing is full of politics now in the States. So, it sort of feels like Joe Biden is responding by doing the polar opposite, by throwing experts at it, which I imagine is something that scientists around the world will be somewhat relieved about.

Nidhi Subbaraman

Certainly, that is a key step, to have good science and good public health advice in the right places, but I guess it remains to be seen how the rest of the country sort of picks up from there because beyond knowing the good stuff, you need to be able to operationalise it and put the resources where they need to be, which is coming to a head, for example, around the CDC’s plan to roll out vaccines. The advisory group that decides who get vaccines first has been thinking for months about who should be ahead of the line and what they should consider and a way to be equitable but because of how the rollout has been so far, experts on the taskforce themselves have been wondering if it’s time to switch gears to accommodate the reality of the rollout beyond the best theoretical advice.

Host: Benjamin Thompson

Yeah, because, of course, one of Joe Biden’s headline statements was 100 million doses of vaccines in 100 days which is a startling figure when you sort of sit back and think about it. But it seems like the machinations maybe underlying that are going to make that potentially quite tricky to reach.

Nidhi Subbaraman

Anthony Fauci, I think, yesterday, was still pretty confident about that being a doable target, but it seems like it would certainly be no trivial effort. It’s going to take a huge push. 100 days is 3-and-a-bit months, but the Biden team has proposed putting US$400 billion to fund the vaccine rollout. They’ve talked about training people in administering vaccine doses. They’ve talked about mobilising and funding the state National Guard efforts to move logistics and manpower where they need to be. They’ve talked about activating these health clinics that serve lower-income communities, having them being involved more closely, and moving vaccine facilities to communities that might not be able to drive out to wherever they have the one place where you can get a vaccine. So, all of these things seem to be addressing the major pain point, but of course we have to wait and see how the change actually comes through.

Noah Baker

To some extent, a lot of what you’re describing is coming in and then making everything that we’ve talked about for quite some time happen. But the pandemic is still changing. There are variants that are happening around the world which are causing concern and worry. To what extent is Joe Biden and his administration continuing to look forward to how things might change in the future as well as just enact stuff that’s already been planned.

Nidhi Subbaraman

I mean, some things aren’t changing. There is the legacy of vaccine hesitancy that has related to all aspects of misinformation and disinformation in this pandemic that they’re going to have to contend with, and installing one person in an administration is not going to change that. We’ve been talking about the new variants and how some countries, including the US, aren’t equipped to be doing the kind of genomic analysis that tracks the new variants, so that’s not going to change overnight, certainly not in the next handful of months. Some of the troubles, unfortunately, that the US has been seeing have been baked into the system going beyond the Trump administration in how science is prioritised. I mean, the best they can do is, I guess, close the door on this event and then begin conversations about how a future pandemic might be something that the US is better poised to beat back.

Noah Baker

That was one of the points that Biden wrote in a letter to his new scientific advisors as well. What can we learn from this pandemic? And it seems like he’s installing people in his cabinet for the future and to really put science at the front and centre where maybe in the last four years it hasn’t been.

Nidhi Subbaraman

That’s a really interesting development. Biden announced his team of science advisors at the Office of Science and Technology Policy on Friday and, for the first time, has elevated the science advisor position to a cabinet position. So, theoretically, this means that Eric Lander, the top geneticist, is going to be in the room with the other major players in the administration more often than his predecessors ever have been. But again, I think that’s a good indication but how that actually shapes up into action going beyond this pandemic really remains to be seen.

Noah Baker

I’m going to ask a question which is, I guess, a bit speculative, but one of the things we’ve talked about a lot is elevating the value of science and scientists and experts, and that’s a lot of what Joe Biden is doing. I’m conscious that a lot of the sort of pushback that supporters of Donald Trump may have to that is that a lot of Donald Trump’s rhetoric worked in the opposite direction, was quite anti-elite, anti-expert and so on. Do you have any kind of fear or worry or do scientists have any fear or worry that this elevation of science again could lead to a backlash among that group of people who, they’re not necessarily happy that the administration is changing and that has been shown in events recently. Is science in danger or perhaps setting itself up to be attacked further?

Nidhi Subbaraman

That’s a good question but, to be honest, that’s not a new question. Science has always prided itself on its ivory tower status and, of course, this pandemic has shown in multiple ways that it really needs to be accessible by people who are making decisions but by people who are hearing them. And there’s been a strong push to appoint people like Dr Nunez-Smith from Yale who chairs the White House taskforce on health equity, I believe. So, getting science to the right people isn’t just whispering in the ears of presidents but also being less lofty to those who aren’t mixed into the enterprise, and that’s a challenge that they have to tackle head on, immediately for the sake of the pandemic and certainly beyond that too. I think science has become politicised in an unfortunate way. That’s always possible to happen if it’s an issue that’s taken over the country. But the other thing still needs to be fixed. When there’s not a pandemic, who gets to hear about what science does and who gets to do the science?

Host: Benjamin Thompson

Maybe sort of final question here. Of course, as listeners are hearing this, it is day one of the Biden presidency. In terms of the response to the pandemic, what are some of the key milestones that we maybe need to keep an eye out for in the not too distant future?

Nidhi Subbaraman

The big milestone is 100 million vaccines in the first 100 days, but we are going to of course be watching the trends after the expected mask mandates are announced. Those are just a handful of things that are going to be top of mind here. Of course, when the pandemic will alter course is the money question that everyone wants to know the answer to that we won’t be able to see for another couple of months or so.

Host: Benjamin Thompson

Well, Nidhi, I hope you’ll come on again to Coronapod to keep an eye on how these milestones are going. But for the time being, thank you so much for joining me, Nidhi and Noah.

Nidhi Subbaraman

Thank you so much for having me. It was great to chat with you both.

Noah Baker

Thanks, Nidhi.

Host: Benjamin Thompson

More from Coronapod next time. Coming up, we’ll be hearing how forgetful fruit flies are helping researchers about a poorly understood brain process. Right now, Noah Baker’s back with this week’s Research Highlights.

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Noah Baker

Helium atoms are stand-offish, rarely interacting with other elements or even with one another, unless that is you get them really cold, close to absolute zero. Then they can be coaxed into fragile pairs or ‘dimers’ with particularly quantum properties. And now, a team from Germany have come up with a new way to study them. The group used strong laser fields to give helium pairs a kick. One laser pulse imparted angular momentum. A second shorter pulse quickly knocks electrons off the pairs. The remaining positively charged ions repel one another, flying apart, and that can be measured. By varying the time between the first and second laser pulses, researchers could measure the dimers’ quantum properties. The technique could also be used to study the lesser explored helium trimer – a group of three helium atoms – as well as hopefully opening a window onto the dynamics of exotic quantum states. Read more in Nature Physics.

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Noah Baker

We all know that getting regular exercise is good for your health, but surely only to a point, right? Well, according to new research, when it comes to your heart, not really. Researchers in the UK gave wearable motion sensors to more than 90,000 people, and collected data on their physical activity for seven days. Then they stayed in contact with those participants for around five years, during which time, more than 3,500 were diagnosed with heart disease. Across all genders, physical activity and heart disease risk were directly linked. The more you exercised, the lower your risk of disease. What’s more, the researchers found no upper limit to the benefit of increasing exercise. The most dedicated exercisers fared better than all other participants, even those that engaged in relatively large amounts of exercise themselves. The authors say their findings still hold, even after accounting for differences in other factors like socioeconomic status. They also say that their dataset records physical activity more reliably than other studies, which rely on participants completing surveys about their exercise habits. Best go for that run then. Read more in PLOS Medicine.

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Interviewer: Benjamin Thompson

Can you remember the last time you forgot something? For me, it happened just this morning when I was getting ready to take my kid to nursery. I was gathering my things together and then she started saying, ‘Daddy, daddy, daddy, daddy,’ so I obviously turned and gave her a smile to make sure that she was okay. And then I just kind of stood there for a second, completely unable to remember what it was I was doing. And then my brain sort of clicked into gear. ‘Oh yeah, keys, I must pick up my keys.’ And I don’t think I’m alone in having moments like this, right? But despite the commonality of this experience, not a lot is known about the neuroscience behind it. A huge amount of research has gone into figuring out how memories are made, stored and recalled, but much less is understood about how they’re forgotten, especially this type of tip-of-the-tongue feeling of temporary forgetting.

Interviewee: Martin Sabandal

A lot of this idea of temporary forgetting or transient forgetting has been in the research domain of experimental psychologists. It has been completely unexplored at the neurobiological level, and so we try to model that in our favourite model organism – fruit flies.

Interviewer: Benjamin Thompson

That’s Martin Sabandal, a PhD student at the Scripps Research Institute in the US, who’s been researching this phenomenon. It turns out that humans aren’t the only ones who experience temporary forgetting and, this week in Nature, Martin and his colleagues have shown a neural mechanism that offers some insight into how it happens in Drosophila fruit flies. Now, although still seriously complex, compared to humans, the Drosophila brain is pretty simple, and this relative simplicity lets researchers look in exquisite detail at individual neurons and work out which ones are active during the process of forgetting or remembering. But how do you make a fruit fly forget? It’s a two-step process, as Martin explains.

Interviewee: Martin Sabandal

First, you have to implant a memory into the fruit fly and that involves training or conditioning the fly to associate an odour paired with a negative stimulus, such as an electric shock. Flies will learn to form this association and later avoid this odour and go toward to odour that was not paired with a shock.

Interviewer: Benjamin Thompson

After some rounds of training, this association gets baked into the flies’ brains as a long-term memory. The next step is to make it forget. In humans, temporary forgetfulness can be induced experimentally by distracting a person just as they’re trying to remember something. And this approach also works in fruit flies.

Interviewee: Martin Sabandal

And so we took very simple distractors that would be also present in the wild, such as strong gusts of wind or air flow, that could distract them from whatever activity or behaviour they’re doing and consistently, memory went down after the presentation of this simple distractor, such as a gust of wind. And what was even more surprising, when we waited one hour after this presentation of stimuli, the memory recovered to normal levels, hence transient forgetting.

Interviewer: Benjamin Thompson

To work out what was going on at a cellular level, Martin and his colleagues focused on the activity of two bundles of dopamine-releasing neurons, one found in each hemisphere of the fruit fly brain. Neurons within this bundle have previously been shown to be important in a different type of permanent forgetting. By activating these bundles, Martin was able to induce transient forgetfulness in the fruit flies, but this wasn’t enough. He wanted to zoom in even more.

Interviewee: Martin Sabandal

We were able to map this transient forgetting phenomenon to a single neuron, one in each hemisphere of the Drosophila brain, and when we saw those experiments, I was astounded and I was in disbelief because it’s pretty amazing.

Interviewer: Benjamin Thompson

Just two out of the roughly 100,000 neurons in the fruit flies’ brain were responsible for the temporary forgetting that Martin saw, and these two dopamine-releasing neurons connect to a specific part of the fly brain.

Interviewee: Martin Sabandal

These dopamine neurons form synaptic contact with the mushroom body axons, and the mushroom body in fruit flies are the memory centres, essentially, and what happened is that when we stimulated this single neuron that synapses into a very specific compartment within the axon, so the mushroom body neurons, we were able to see this transient forgetting effect.

Interviewer: Benjamin Thompson

Quite how the release of dopamine into this specific area of the fly brain leads to the temporary stopping of memory retrieval is unclear, and there are lots of other questions too. Are there multiple groups of neurons that respond to different sensory distractors, for instance? But there’s two questions that maybe stand out above all others when it comes to this poorly understood brain phenomenon. Why does transient forgetting exist at all? Although the mechanisms behind it could be very different, why do both fruit flies and me get moments of, ‘Wait, what was I doing?’ Martin suggests that maybe this system provides brains with some flexibility, allowing them to refocus onto something that’s going on right now. In my case, giving my daughter my full attention when she needs me at the expense of forgetting I need to pick up my keys for a few seconds. Now, I don’t think fruit flies need to remember their keys very often, but transient forgetting could be involved in helping them survive the day.

Interviewee: Martin Sabandal

So, for example, when flies have this memory to go to, let’s say, a food source and what if by some random chance there’s a predator, and so what they need to do is adapt this situation, escape, and then come back later on to that food source again. So, it leads into this idea of adaptability and survival mode, but you can’t efficiently do that without having to temporarily forget what it is that you’re doing at the moment and then go back to it later on. I think it honestly feeds into our abilities, whether you’re an animal, a fly, a dog or a human, to remain flexible to any situation and, yeah, there’s more questions that need to be asked after that.

Interviewer: Benjamin Thompson

That was Martin Sabandal, and we’ll put a link to his paper in… erm… in the show notes of course, where you can find out more about fruit fly forgetfulness.

Host: Nick Howe

Finally on the show, it’s time for the weekly Briefing chat where we discuss a couple of articles that have been highlighted in the Nature Briefing. Ben, what have you found this time?

Host: Benjamin Thompson

Well, Nick, I have been looking at a story that was reported in The Guardian and it was all about this kind of economic analysis that was performed by a group of thieving monkeys.

Host: Nick Howe

Okay, there’s so many interesting things in this sentence. One, thieving monkeys, but also they’re doing an economic analysis? I can’t do an economic analysis. How are these monkeys doing an economic analysis?

Host: Benjamin Thompson

Well, Nick, let me tell you about these monkeys first. This is a group of long-tailed macaque monkeys that roam around this ancient Hindu temple in Bali, and these monkeys are kind of infamous, I guess, for basically just robbing tourists of their possessions and holding them to ransom until they’re offered some food as kind of a payment, and this is very much where their economic analysis comes in.

Host: Nick Howe

Right, okay. Yeah, I think I’ve seen videos of these monkeys doing this, but they’re not just taking stuff, they’re holding it to ransom, so are they sort of assessing how much people might have? Is that what their analysis is?

Host: Benjamin Thompson

Yeah, they’re very, very shrewd, it turns out. So, a team of researchers has been looking at this monkey population and filming them for 273 days and looking at their interactions with temple visitors, and these monkeys seem to have a clear strategy. They very much aim to steal higher-valued items from temple visitors – cameras, phones, wallets and what have you – and then they sort of just steal them away and then they barter with the temple staff for their safe return. And as I say, they’re really, really shrewd about this. They know which are the higher-valued items and will barter for longer to get more food.

Host: Nick Howe

That is fascinating because one, the value of these items is meaningless to the monkeys, apart from it’s got a value to the humans and they know they can trade it for food. Wow, these guys are incredibly clever.

Host: Benjamin Thompson

Yeah, absolutely, and so some of these negotiations took quite a long time apparently. The longest wait for an item to be returned was 25 minutes, with 17 minutes of bartering, and if a monkey had stolen my camera, I think I would be sweating a little bit at this point. And for lower-valued items, this time was much shorter. So, there’s lots to be learnt here as well. This is obviously quite a challenging kind of bit of mental gymnastics these monkeys are doing. They’re making economic decisions, as you say, based on the perceived value of an item. Now, bartering behaviour has been studied a lot in the lab, I guess, but this is kind of in situ, which makes it a very, very interesting piece of work.

Host: Nick Howe

Yeah, I mean, what could we learn about maybe economics for humans from this?

Host: Benjamin Thompson

Well, the researchers are talking about what they can learn about economic decisions, but I think what’s super interesting as well is this behaviour is learnt by these monkeys and it’s remembered and shared. So, apparently, these behaviours have been maintained in this population for about 30 years. So, well, there’s lots more to learn about this kind of bartering behaviour and economic impact done by non-human primates.

Host: Nick Howe

This is a deeply fascinating story, Ben. Yeah, I don’t know how I’m going to top that one but I’m going to give it a try, and this story that was in Science this week is a shocking discovery.

Host: Benjamin Thompson

I sense a heavy, heavy pun here, Nick. Right, what’s the story?

Host: Nick Howe

I may have hammered that home slightly too much, but this story is about electric eels, thus shocking. And basically, it’s been thought for a long time that they hunt solo. These eels, they can get really big, they have no need for other eels to hunt things. They’re very good at it themselves. But it actually looks like in some situations, they will hunt in packs.

Host: Benjamin Thompson

Well, I mean, there’s a Jurassic Park reference in there somewhere Nick, I’m sure, but let’s kind of talk about this story then. So, what do electric eels hunt? What do they eat?

Host: Nick Howe

So, fish in rivers. So, these are electric eels, they’re called Electrophorus voltai because scientists are very inventive, and they’re found in rivers in the Amazon and in Brazil particularly, this was. They basically will shock fish and then they’ll eat them because they’ll be immobilised from being shocked. But what appears to be happening is, at certain times of year, the so-called low season when waters are lower, they’ll actually group up into gangs of ten eels and they’ll essentially herd the fish into places where they get blocked in, shock them, and then they’ve got a whole school of fish that they can feed on.

Host: Benjamin Thompson

Wow, and do the shocks magnify each other? Are you getting sort of one super shock from this group of eels?

Host: Nick Howe

I don’t think so. I think it’s more about corralling the fish into an area where they’re trapped and there’s no escape, and one researcher who was interviewed for this story said that it’s only been identified so far in the low season when the water is low, but in the high season, they don’t think it would work because the fish would be able to get away. So, this may be a behaviour that they’ve just developed because it works particularly well under certain circumstances.

Host: Benjamin Thompson

Well, another story then, Nick, of learned animal behaviour. I mean, where do the researchers want to take this one?

Host: Nick Howe

Well, there’s so much we don’t know about this. It’s only been observed in like one small part of the Amazon, in one river, essentially, and so we don’t know how widespread it is. And what researchers are interested in doing is maybe looking at the genomes of these eels to see if there are any genes associated with social predation. You find these in like whales and dolphins and things like that. So, that could be a predictor of whether there’s a genetic component to this, how recently it might have come about and maybe if they look at the genomes of a lot of eels in a lot of places, they’ll see how widespread this behaviour is.

Host: Benjamin Thompson

Well, Nick, congratulations on being our new eel correspondent, and I look forward to getting some more insights on this in the forthcoming weeks, months and years. But let’s leave the Briefing chat there for today. And listeners, if you’d like to know more about the stories we’ve discussed, you’ll find links to them in the show notes. And if you want more stories like this delivered straight to your inbox then make sure to sign up for the Nature Briefing, and there will be a link to that as well in the show notes.

Host: Nick Howe

That’s all for this week. But don’t forget you can catch up with us on Twitter – we’re @NaturePodcast – or you can even send us an email – we’re podcast@nature.com. I’m Nick Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson. See you next time.