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Podcast: Ridding New Zealand of rats, making choices in the grocery store, and what to expect in 2017

This week, ridding New Zealand of rats, making choices in the grocery store, and what to expect in 2017.

In this episode:

00:41 Ridding the land of rats

New Zealand has cooked up an ambitious plan to exterminate all its rats by 2050. News Feature: The big cull

06:52 Research Highlights

Wild pigs’ speedy spread, and mini machine delivers cancer drugs. Research Highlight: Invasive pigs spread across US; Research Highlight: Mini machines deliver drugs

09:13 Supermarket selections

Thousands of grocery store transactions help psychologists figure out decision-making in the real world. Research article: Riefer et al.

14:55 What to expect in 2017

Space missions, quantum supremacy and new drugs on the market. News: What the new year holds for science

Never miss an episode: Subscribe to the Nature Podcast on Apple Podcasts, Google Podcasts, Spotify or your favourite podcast app. Head here for the Nature Podcast RSS feed.



This week, ridding New Zealand of rats, making choices in the grocery store, and what to expect in 2017.

This is a transcript of the 11th February 2016 edition of the weekly Nature Podcast. Audio files for the current show and archive episodes can be accessed from the Nature Podcast index page (, which also contains details on how to subscribe to the Nature Podcast for FREE, and has troubleshooting top-tips. Send us your feedback to

Kerri Smith: This week: how we understand the evolution of religion.

Dominic D. P. Johnson: It might not just be a coincidence that big societies have these big omniscient, omnipresent Gods.

Adam Levy: And, could investors who do nothing about climate change end up in court?

Howard Covington: The risk from future climate damage is big enough to be taken into account by investors who have an obligation to manage risk for their clients.

Kerri Smith: Plus the law that governs the computer chip industry may be faltering. So, what next? This is the Nature Podcast for February the 11th 2016. I'm Kerri Smith.

Adam Levy: And I'm Adam Levy.


Kerri Smith: About a year ago, I replaced my smartphone with a newer version. Despite being slimmer and lighter, it had more storage, more RAM and the camera was better and as a consumer I confess I just kind of expected that. Dan Reed knows this feeling better than most. He's at the University of Iowa now but he used to be Corporate Vice President at Microsoft. Nature 530, 144–147 (11 February 2016)

Daniel Reed: Consumers have been conditioned to believe that every couple of years, their devices will be more powerful, they'll be cheaper and that may not always be the case. The whole economic engine based on that growth model, which says every new generation of device is smaller, faster and one sells more of them, that's getting harder and harder to deliver on.

Kerri Smith: This principle of smaller, faster, more sales is a target the computer chip industry set itself decades ago. It's based on something you might have heard of, Moore's Law.

Daniel Reed: Back in the 1960s, Gordon Moore, who was one of the founders of Intel observed that the number of transistors one could place on a chip was doubling every 18 to 24 months. And, the semiconductor industry has worked to make that true for most of the last 50 years.

Kerri Smith: Gordon Moore didn't mean to make a law. His original prediction was a casual remark in an article in Electronics magazine in 1965. He noticed that in a few years of making silicon chips, engineers had about doubled every year the amount of components that could fit on a circuit. And he just said, well that's going to have to carry on if we're going to make computing cheaper. If in 1965, there were up to 60 components on a chip, he predicted 10 years later there would be 65,000. It was more a business plan than a law. Here's Gordon Moore himself in an Intel video from 2015, celebrating 50 years of the law.(Excerpt from Intel video)Gordon Moore: My real objective was to get the idea across: we have the technology that's going to make electronics cheap but I didn't expect a thousand-fold increase in complexity to be very accurate.

Kerri Smith: But it has been, for decades. A lot of the things that Moore had very far-sightedly predicted in his article came true. Remember it was 1965 when he wrote...“Integrated circuits will lead to such wonders as home computers or at least terminals connected to central computers; automatic controls for automobiles and personal portable communications equipment. The electronic wristwatch needs only a display to be feasible today.”

Kerri Smith: And in the past 50 years we have indeed developed PCs, distributed computing, driverless cars, cell phones, even the Apple watch. No wonder the industry has been keen to stick with Moore's bounteous law as a governing principle. But...

Daniel Reed: No exponential is forever except in the mathematics text books and that's what we have been chasing for the last 50 years and so at some point, there is an inflection point and you say, okay, it's time to think about new alternatives.

Kerri Smith: The inflection point, the new alternatives: that's happening now. Next month the industry will announce that they will no longer cling to Moore's law as a governing principle. Making chips that conform to the law has a couple of problems: more components in smaller spaces means they get too hot; and when they're small, the chips start working in different ways. At very tiny scales, quantum effects start to interfere. So, what next? May be the devices could talk a different language. Instead of using electricity, for example, why not use magnetism? Paolo Gargini is a Silicon Valley veteran who has worked at Intel and now works at Stanford University. He says that researchers are working on new kinds of devices.

Paolo Gargini: They use different effects. They use, besides the electrical effects, they use some magnetic effects or a mix of the two and they behave differently and they have different features. So they're not going to be a direct replacement for transistors but they will open different architecture for the way you design your systems.

Kerri Smith: Magnetism would be great for consumer devices because it would also use less power. It wouldn't work for every application. There's a slight decrease in speed too which doesn't matter for the iPhone but does make a big difference for a supercomputer. Another option for future design is to do what lots of architects have done when pushed for space: go up.

Paolo Gargini: If you look at places like Manhattan or you look at Hong Kong or you look at Shanghai, you see that when they ran out of space, they began building skyscrapers. And so, similarly, the semiconductor industry is going vertical. What it means is that the devices, instead of being cramped together on a flat surface, they're now beginning to be built vertically and in fact some of the memory houses have already announced some memory that uses 32 layers of memory or even 48. So with this approach we will be able to easily continue Moore's Law for the next 10-15 years, given that we have opened the third dimension, the vertical dimension.

Kerri Smith: The only thing that could rain on this parade: it's expensive developing new technologies. Dan Reed again...

Daniel Reed: My bet is we'll run out of money before we run out of physics, because the cost of building next generation semiconductor fabrication lines has gone from millions of dollars to billions of dollars and continues to escalate. But I don't want to be too pessimistic. I absolutely believe innovation will continue. The rise of the 'Internet of things' is one of the great events on the horizon and that's actually predicated on billions of very small and relatively simple devices.

Kerri Smith: The next wave then might be all our internet enabled fridges, watches and wardrobes powered by technology we have already. Many in the industry have questions about a future ungoverned by Moore's law but Paulo Gargini doesn't think the law is so unhealthy after all.

Paolo Gargini: So, the reality is that by now five or six methods have come and gone to realise the Moore's law. And what people confuse is that when one of the methods reaches the limit then they associate this with the end of Moore's law. Actually we will accelerate Moore's law but it will be by a different method.

Kerri Smith: Moore's law is dead. Long live Moore's law.


Kerri Smith: There's a feature by Mitch Waldrop all about Moore's law and what comes next. That's at this week. You were listening to Paulo Gargini and before him Dan Reed.

Adam Levy: Coming up, the impact of religion on being nice to people and why shareholders should manage the risks to their business from climate change. But first it's Shamini Bundell with the Research Highlights.

Shamini Bundell: Planting trees won't necessarily slow down climate change; it all depends on the species. That's according to a study of Europe's forests over the last 250 years. Forests here have been chopped down to provide fuel and clear land, but they have rebounded. So now we have 10% more forested land than in 1750, but that has actually released carbon overall because we're planting conifers in place of deciduous trees and conifers absorb less carbon and get harvested for timber. And, darker leaved conifers also raise local surface temperatures. Find the study in Science. Nature 530, 132 (11 February 2016)Morning Lark or night owl: it's written in your genes. Three separate teams including one from the personal genomics company 23andMe report gene variants associated with springing out of bed early. Each team found a dozen or more variants linked to someone's preferences for sleep times. Many of the code changes were in or near genes that govern daily rhythms in our bodies. The results could provide a way to study sleep conditions like insomnia, which is linked to morningness. Find one of the papers in Nature Communications and the other two on the preprint server bioRxiv. Nature 530, 132 (11 February 2016)


Adam Levy: In December last year the world agreed a climate deal. Forging this deal was mostly the job of the world's governments but the private sector can't ignore climate change either. Jennifer Morgan of the World Resources Institute gave us her thoughts just minutes after the deal was struck. Nature 530, 156 (11 February 2016)

Jennifer Morgan: Investors have to shift their funding out of high carbon. The signal is clear. It is so clear, and if you want to have a profitable company or bank or anything in the future, you've got to go renewable.

Adam Levy: Many believe that a vital part of the climate's future is in the hands of the private sector. The global value of companies in the stock exchange is huge, around 70 trillion dollars, and with lots of money comes lots of power. In theory, the shareholders of these companies are able to influence the way they are run and so could push them to become more green. But, like all good plans, just because it can happen doesn't mean that it will. According to Howard Covington from the Turing Institute in London however, this may well be changing. In a comment this week, Covington and colleagues from the fields of environmental law and economics suggest that in the future investors who don't act on climate change could find themselves being taken to court by the very people whose money they're managing. Covington came into the studio to talk to Noah Baker.

Howard Covington: If you are, by profession, an investor in quoted companies you are very concerned that the future will be good to you and that your investments will rise in value. The most recent work on the likely effect of global warming on the world's economy is that it might cause quite a lot of damage; it might cause damage to long-term growth. Of course, when I say it might, it might also not cause that damage. The world's leading economists are quite split on this. The fact of the matter is that we don't know and in the financial community, when you don't know what the answer is you just acknowledge that there is a risk there and you seek ways of dealing with the risk.

Noah Baker: That sounds like a logical step, but you're suggesting in this comment piece that there is more than just a logic to it: that there is actually a legal reason to be doing this.

Howard Covington: Some investors, for example, the investors that look after people's pension plans or that look after their unit trust investments – if they are using their unit trusts to save to pay off a mortgage or for their children's education or whatever it might be – some investors have fiduciary obligations to clients. The logic of our analysis is that the risk from future climate damage is big enough to be taken into account by investors who have an obligation to manage risk for their clients. And if such client finds that this risk isn't being properly managed, he may have a legal case to bring against such an investor.

Noah Baker: And this same sort of concept applies not only to shareholders in companies but also to governments. There was a famous case that happened just last year in the Netherlands.

Howard Covington: There was a case in the Netherlands called the Agenda Case where a citizens' group brought an action against the government which required the government to do more to manage the risk to its citizens that future climate change would bring. And the court found in favour of the citizens and said yes indeed the government must do this. That case has been appealed and we're waiting to see what's going to happen, but meanwhile the Dutch government has increased its ambition for reducing emissions. So it's already made some progress.

Noah Baker: To what extent will the latest research play into this risk? So, the risk, I assume, is informed by climate modelling for example or is that not really the way it works?

Howard Covington: Well, it's quite... that's a very interesting question. In many senses, the climate models are quite good enough for the purposes of considering these risks. Where the difficulty lies is in the economic models. So, for example, there are models which suggest the world's economic product might be 4 or 5% lower than it would have been without the warming. Well, 4 or 5%: it's a setback of 1 to 2 years as far as a financial investor might be concerned. At the other end of the scale, there are climate economists who think that a world Gross Domestic Product might be 50% lower than it would have been without warming. Now 50% is a large number and if one expected that by the end of the Century, world Gross Domestic Product might be 50% lower than without warming, that would make a difference right now to the value you would attach to an investment portfolio simply because your dividends would be that much lower than you thought.

Noah Baker: Now there's a lot of uncertainty going forward, but those involved are starting to connect up these dots now, these legal dots and these obligation dots, as it were. Is this essentially a sort of a good news story from the perspective of the climate?

Howard Covington: I think it is a good news story. I mean, there is an enormous amount that investors can do about climate change. There is a revolution in the supply of energy which has begun and which will only gather momentum. Investors like these sorts of revolutions because there are huge gains that they can make by making shrewd investments. So, on the plus side of the balance sheet, it's a tremendously exciting time. On the other side of the balance sheet, on the negative side: if these risks aren't managed properly we could all end up in a world where the wonderful growth machine that we've come to rely on and enjoy so much fails. And that's not a place where investors should want to go. So, there's plenty of reason, both for them to be very excited to push the energy transformation along and for them to be cautious and thoughtfully managing risk.

Adam Levy: That was Howard Covington speaking with Noah Baker.


Kerri Smith: Shamini Bundell has been taking a break from the nice simple science of physics and biology to learn some more about Gods and how they might have shaped human civilization. But first she challenged Adam to a game.

Shamini Bundell: Adam, this is a very easy game, even you should be able to do it. So I've got some coins here and you're going to split them between us: either in my cup or your cup. The important thing is what you're going to do is you're going to decide in your head who you want to give the coin to, then you're going to flip the coin, heads it goes to you whoever you just picked in your head, tails to the other person.

Adam Levy: Okay.

Shamini Bundell: Okay, flip the coin.

Adam Levy: Ah!

Shamini Bundell: Oh, thank you, that's very kind of you. Okay...

Adam Levy: Oohhhh!

Shamini Bundell: One for you.

Adam Levy: One in for me.

Shamini Bundell: Okay, so it looks like you're playing pretty fairly given that I actually ended up with more money than you. What would you think, what would you expect to happen, if you got loads of people to play this and it was completely anonymous and then they actually got to keep the money as well.

Adam Levy: So, I don't get to keep money?

Shamini Bundell: Well, you might think that the players would cheat and that the player's cup would end up with maybe a bit more than 50% of the coins?

Adam Levy: You never said I can't keep the money.

Shamini Bundell: Well, this game is very similar to an experiment described in a Nature paper this week as author Benjamin Purzycki explains. Nature 530, 327–330 (18 February 2016); Nature 530, 285–287 (18 February 2016)

Benjamin Grant Purzycki: So, games based on the assumption that people are probably going to bend the rules and favour their own cuts, and people do.

Shamini Bundell: Benjamin is from the University of British Columbia in Canada, but rather than stick with North American University students like many studies, Benjamin and his team did this experiment with people from all over the world, Siberia, Brazil, Tanzania, Fiji and with people from all sorts of different societies and religions. And yes, on average people did always end up giving more money to themselves, but that wasn't what interested Benjamin.

Benjamin Grant Purzycki: The central question we had was what religion's role was in the expansion of cooperation in sociality. And we wanted to test whether or not certain kinds of gods play a role in whether or not people play fairly towards other people they'd likely never interact with?

Shamini Bundell: The societies they studied had a whole range of Gods, from mean Gods to just plain uninterested.

Benjamin Grant Purzycki: Well in terms of moralistic Gods, the Abrahamic Gods are prototypically moralistic.

Shamini Bundell: That's the omniscient God of Judaism, Christianity and Islam.

Benjamin Grant Purzycki: So, you can say quite intuitively that God doesn't like it if you steal money from other people. However when you ask students from southern Siberia does the local spirit here care whether or not you steal money from other people, they're sort of reluctant to answer because that's not how they talk about it.

Shamini Bundell: The results in this paper show a clear correlation between people's God and how much they tended to cheat in the game. So, the more the God was interested in punishment, the more fairly the money was divided. Now there could be a few explanations for this. I asked Dominic Johnson from the University of Oxford who has written News & Views article on this paper to give me some context.

Dominic D. P. Johnson: For quite a time now, in the field, there's been this idea that moralising Gods and in particular Gods that punish might be effective promoters of cooperation and an effective deterrent against self-interest. But a lot of the studies that got out and test those ideas have been a little limited. So, this study is quite remarkable because it looks in great detail at all of the participants' personal beliefs and is then able, in a large sample size, across multiple cultures to see whether those individual beliefs then predict their behaviour and in particular their willingness to cooperate or to be generous to distant strangers.

Shamini Bundell: Cooperation has always been important in human societies and it's easily enforced when you're living in small tribes of close relatives. But, as Dominic explains, this changes as tribes grow.

Dominic D. P. Johnson: In large societies, where you have anonymous strangers, it's especially problematic because free riding is so much easier. So it's always been a puzzle in the field of evolutionary biology and anthropology to figure out exactly how we managed to get to these enormous society sizes and still hold together. And of course many things might contribute to this, but religion seems to be one very powerful way of deterring self-interest and promoting cooperation, even amongst strangers. And a supernatural eye in the sky could be an extremely effective deterrent.

Shamini Bundell: And there's some evidence for this from history.

Dominic D. P. Johnson: As societies got bigger, the Gods important to those societies got bigger too. It might not just be a coincidence that big societies have these big omniscient, omnipresent Gods, but in fact that was perhaps necessary for the societies to get large in the first place.

Shamini Bundell: But as Benjamin Purzycki explains, these psychological effects aren't always forces for good.

Benjamin Grant Purzycki: On the flip side too is that the kinds of cooperation required to engage in all sorts of awful things, religion also contributes to that. So if you look at contemporary issues of religiously motivated or religiously rationalised violence, you often see people who are engaging in some of the most expensive (from a biological perspective) behaviours you can imagine, namely suicide, but it's on behalf of a particular group.

Shamini Bundell: For, Dominic Johnson, examples like this and like the altruistic behaviour shown in the game, lead to a much bigger question.

Dominic D. P. Johnson: So I would say the big argument in the field now is whether religious beliefs promote reproductive success. We do not have these religious beliefs by accidents. They're there because they helped us in the past. We have a lot of evidence that it promotes cooperation or like in this game it promotes generosity but we don't yet have good evidence that religion helps to spread genes.

Adam Levy: That was Dominic Johnson who's written a News and Views article on Benjamin Purzycki's paper. Both pieces are available at and if Shamini Bundell ever offers you a chance to win money, please be aware that it's probably a scam.

Kerri Smith: Plenty of news to choose this week and making these selections, it's Lauren Morello, now our US chief of Correspondence. Now first of all, we've been hearing quite a lot about harassment, unfortunately, rearing its head. Geoff Marcy, the astronomer, resigned from Berkeley and then in the last couple of months there have been another few cases. What's the story that you have this week about harassment? Nature 530, 138–139 (11 February 2016)

Lauren Morello: You're right. There have been a lot of harassment cases coming to light in the United States over the last couple of months and big funding agencies like the National Science Foundation and NASA have put out pretty strong statements saying we're not going to tolerate sexual harassment by scientists who take our grant money. But, what our story goes into is it's really not so easy for funding agencies when confronted with one of these cases to just cut off somebody's grants.

Kerri Smith: Because I suppose other people depend on it, the money has already gone into the university system...

Lauren Morello: That's part of it. In a lot of cases, the money keeps flowing to support doctoral students or postdocs in the lab of someone who's been found to commit harassment, with the idea that we shouldn't punish other innocent people for the transgressions of a PI. But also there's just a really complicated process, the kind of legal landscape of all of this is still something that people are trying to understand.

Kerri Smith: Right, so there's almost a set of new rules that's coming into play but it seems like it's new ground for a lot of people.

Lauren Morello: Twenty or thirty years ago, I think a lot of US science funding agencies used to classify sexual harassment or assault as a form of research misconduct, but these days agencies deal with sexual harassment and assault under US law called Title IX. Title IX was enacted in 1972 and it specifically addresses discrimination based on sex in any educational institution that receives US government funds. That legally includes things like harassment and assault and the way the process generally works, the home institution investigates through its Title IX office which enforces that federal law and then if a person is found to have violated university policy on these counts that gets forwarded often to the person's funding agency and then the funding agency tries to figure out what to do. So universities can work with funding agencies to reassign those grants to new principle investigators but in some cases funders might just want to cut off grants. What's interesting is that for example the NSF has never actually banned scientist grant recipients for violating Title IX.

Kerri Smith: Right, so I was going to say, has anyone... It's all very well, Title IX existing, but has anyone acted upon it yet?

Lauren Morello: As far as we can tell, for example the National Institutes of Health and the NSF have never cut off anyone's grant funding for a Title IX violation. They theoretically have the power as well to cut off an entire institution's funding if an institution is found not to comply with Title IX and they've never done that either.

Kerri Smith: Do we know what's happening in any of the cases that have been very recent like Geoff Marcy at the University of California, Berkeley? What's happening to his money?

Lauren Morello: Geoff Marcy had a mix of public and private grants. Some of his private money came through this $100million project, Breakthrough Listen, to search for extra-terrestrial intelligence and that private grant money was easily transferred to new principal investigators. As far as the public money, the University of California, Berkeley, is working to designate new principal investigators to handle Marcy's two NASA Grants which have a total value of about $1 million.

Kerri Smith: We're moving onto a very different subject area and another story this week concerning the state of very old growth forests in Tasmania. They're not doing very well with the recent bush fires. Nature 530, 137–138 (11 February 2016)

Lauren Morello: Bush fires have been burning at multiple sites in northwestern Tasmania and Australia. Since the middle of January, there have been two big lightning storms that have ignited these fires. Bush fires are not necessarily that unusual but normally they strike in ecosystems that have evolved to cope with fire and these bush fires in Tasmania are encroaching on forests that are these ancient remnants of ecosystems that date back more than a 180 million years to when Tasmania was part of what's called the Gondwana Super Continent before it broke off from that and these ecosystems are full of really old trees, some of them are 1000 years old, that just have not adapted to cope with fire.

Kerri Smith: Is there any way that these trees in these fire susceptible regions might be protected in any way or do we just have to watch them as they burn?

Lauren Morello: There has been an active discussion in Australia amongst scientists about what to do here because scientists are worried about this year's bush fires but they're also worried about how the climate is changing and suspect that bush fires like this may become more common. At least one researcher has proposed taking seeds from these species in this ancient forests and conserving them in another location to keep them safe from fire. Essentially, to make sure that they live on.

Kerri Smith: But ultimately the prediction of course is that climate change might worsen the scenario for this area in general and they can't be protected forever I suppose?

Lauren Morello: That's true but I think this is a common story in ecology and a common story for ecologists grappling with the effects of climate change on ecosystems that are starting to suffer. Having something is better than nothing.

Kerri Smith: Lauren Morello, thank you very much for joining us. More at where you can also keep an eye on lots of other bits and bobs like the latest on those gravitational wave rumours that we talked about in last month's back chat. There's also a video explaining how the LIGO facility plans to find the things. That's at

Adam Levy: And when you're done browsing around, why not hop over to iTunes and leave us a review?

Kerri Smith: Finally, a correction. Two shows ago, we featured an exhibition about Elizabethan scholar John Dee and his library. The curator Sarah Backhouse gave me a tour, only I mistakenly called her Emma in the introduction. Sorry Sarah and thanks again for the tour. I'm Kerri Smith.

Adam Levy: And I'm Adam Levy.



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