Host: Benjamin Thompson

Welcome back to the Nature Podcast. This week, the state of play for social priming…

Host: Nick Howe

And all the latest sounds from a big acoustic meeting in the US. I’m Nick Howe.

Host: Benjamin Thompson

And I’m Benjamin Thompson.

[Jingle]

Interviewer: Benjamin Thompson

First up on this week’s show, there’s a feature out in Nature this week about a branch of psychology research called social priming. Science writer Tom Chivers has been looking at the history of social priming and some of the big claims made in early experiments which, in many cases, have failed to stand the test of time. He popped into the studio for a chat earlier this week, and I started by asking him what exactly social priming is.

Interviewee: Tom Chivers

Social priming is the idea that you can give people these subtle, unconscious cues and change their behaviour, sometimes in quite dramatic ways. It stems from an older idea of priming in general. One of the most famous stuff was semantic priming – that you could give someone a word, for example, ‘nurse’, and then if you gave them related words like ‘doctor’ or something, they’ll read them more quickly. They’ll understand them more quickly than if you have them an unrelated word like ‘brick’. Social priming or behavioural priming is a slightly contested term, but it essentially means that you can use those same ideas of priming unconscious ideas to change people’s behaviour, and the idea certainly used to be that you could prime them to do some quite spectacular changes of behaviours. And there was one very famous example where if you did that same sort of scrambled sentence task, but full of words like ‘age’ and ‘wrinkle’ and ‘bald’ and ‘Florida’ and ‘bingo’, then when they left the experiment afterwards, they would walk more slowly down the corridor because they had been primed with ideas of age and felt more old.

Interviewer: Benjamin Thompson

And this area of research was very popular. On what sort of scale was this going on?

Interviewee: Tom Chivers

In the 80s and 90s, especially towards the early 90s, it became much more that people started having these ideas that you could do these more dramatic behavioural things, and for a period of about 10 or 15 years, it was incredibly fashionable and popular. There were psychological departments all over the globe talking about it, so this was obviously a big, major part of psychology and there were really interesting or bizarre ideas that were come up with. The one that loads of people quoted to me as sort of, ‘You won’t believe people thought this would work,’ was they put one group of people sitting inside a 6 foot by 6 foot cardboard box and one group of people sitting outside a 6 foot by 6 foot cardboard box and had them solve sort creativity puzzles and the ones that were outside the box did better because they were ‘thinking outside the box’. It seems bizarre and yet they were finding these results and getting a P value of less than 0.05, and to all the values of psychological science, this was working.

Interviewer: Benjamin Thompson

And so here we are then, so lots of work going on, lots of funding coming in, presumably, as well, but things aren’t necessarily too healthy and what you’ve been looking at in your feature is the field trying to replicate the field, as it were.

Interviewee: Tom Chivers

Around 2011, I think off the top of my head, three things happened that really shook everyone’s faith in social priming in particular and social psychology more broadly and lots of science as well. So, one of the things was a fascinating and kind of cheeky study called False-Positive Psychology which came out. That was meant to show the problems of statistics and it showed that you could take a reasonable two reasonable sample sizes of two groups of 20 people and play one of them the song When I'm Sixty-Four and one of them a different, unrelated song, and apparently, up to the standards of social psychology – P less than 0.05 – it showed that listening to When I'm Sixty-Four literally made them younger. This obviously wasn’t true and they showed that you can do this by doing lots of different analyses and lots of different things that you measure and then only publishing the one that you find – sort of classic P-hacking. And then at the same time, loads of things started to not replicate. Lots of the people who’d worked in the field or in sort of related fields, they’d all been having conversations around the water cooler saying, ‘I tried to replicate this study by x, didn’t find it, I’m a terrible researcher, I must be really stupid,’ and then when these things started to fail to replicate, they’re all, ‘Oh my word, this is actually not me - a lot of this stuff is just not real.’ Loads of people were telling me that of all the really dramatic, interesting findings in social priming, that it didn’t know of any that had replicated.

Interviewer: Benjamin Thompson

So, we have this replication crisis then, and this is by no means unique to this field. A lot of fields of science are looking at this replication of results and what have you, but it does seem then that statistics and statistical interpretation played an important role, and so where is this field now then? If people are trying to replicate work and struggling to do so, what’s left for the field of behavioural priming?

Interviewee: Tom Chivers

It seemed to me like a lot of people felt like oh well, this is just scorched Earth now – this was a phrase that was used to me a couple of times – and it does seem that a lot of the sort of more wild stuff, I think there’s less work like that going on. Some of it hasn’t replicated, some of it hasn’t been attempted to be replicated, but then there are other people doing what seems to me as sort of more understandable work. So, one person I was speaking to is using, if you prime people with ideas about ‘diet’, ‘trim figure’, ‘slim’, ‘healthy’ and that sort of stuff, if you’re someone who’s worrying about your diet and you sort of see the words ‘try and eat healthily’ on a menu or something like that, then you’re more likely to make healthier decisions. So, that sort of work is still going on.

Interviewer: Benjamin Thompson

In many cases, if this brand has become tarnished, is there still valuable information from some of these old studies, and what lessons are being learnt by researchers now to try and avoid issues that have arisen in the past?

Interviewee: Tom Chivers

Entirely aside from whether or not the concept itself works, which I think the idea that you can prime someone with the word ‘nurse’ and they read the word ‘doctor’ more quickly, that’s so uncontroversial. There’s lots of things in that sort of area that are uncontroversial and true and then it sort of bleeds into a more controversial area. Where you draw the line of it being useful is hard to say. But there are things that have come out of all of this, like the Many Labs project, which are essentially collaborations of many dozens of labs around the world which all try and replicate the same studies, and instead of having one lab doing an n = 40 study, which will never be that statistically powerful and will be prone to false positives, now you’ve got n = 7000 or something like that, and if you don’t find something you can be pretty confident that it’s not there or if you do find something you can be pretty confident it is there. I heard a few people saying that that’s still not perfect, but certainly the idea of ‘small n’ has been rapidly addressed and also much more people are using pre-registered studies so one people mentioned a lot is Registered Reports, which is a fantastic idea that if journals sign up to publish a study on the strength of the methods rather than on the strength of the results so you can say that if a null result comes in you say, well, this is still interesting, but we’re not going to hide it away in a file drawer and we still put it in to the scientific records.

Interviewer: Benjamin Thompson

Well, maybe finally then on this one, so the field has changed a lot then from these bold claims to the issues in the middle and then maybe to where we are now. Where next, do you think? From your reporting, from this feature, where do you think social priming goes?

Interviewee: Tom Chivers

So, some people are still using it really interestingly, but they are using these simple ideas, like goal priming, where you can put an idea like diet in someone’s head and if they care about dieting it will remind them, and that can be used as a tool in sort of nudging people towards a behaviour that they more want to carry out. So, it has it uses, but I think this sort of efflorescence of excitement about these really sort of almost Freudian ideas of the subconscious controlling our behaviour in these really dramatic ways, the impression I get is that that has died away.

Interviewer: Benjamin Thompson

That was Tom Chivers. You can read his feature, which delves even further into the world of social priming, over at nature.com/news.

Host: Nick Howe

For those of you who may not have heard, we’ve launched our 2019 listener survey. Thanks to everyone who’s completed it already. We’ve had some great feedback but we want even more. Head over to go.nature.com/podsurvey19 to fill it out and if you do, you’ll get to see our special behind-the-scenes video showing us all in action. Back to the show now though and it’s time for the Research Highlights, brought to you this week by Dan Fox.

[Jingle]

Dan Fox

Killer whales and humans share one trait that’s rare among mammals. Females of both species live for a long time after they stop being able to reproduce, and while it might not seem like a good idea to compare your grandmother to an orca, researchers have demonstrated that killer whale grandmothers, like their human counterparts, help increase the survival of their grandoffspring. The authors of a new study examined over 40 years of census data looking at two groups of killer whales of the west coast of the US and Canada. Controlling for annual salmon abundance, they found that in the two years following a grandmother whale’s death, the survival of grandoffspring was reduced. They also found that the grandmother effect was larger when the grandmother whales were post-reproductive. This may be because grandmothers can provide more help when not reproducing themselves. Find that research at Proceedings of the National Academy of Sciences of the Unites States of America.

[Jingle]

Dan Fox

A team of archaeologists have failed in their attempt to replicate a voyage made 30,000 years ago, suggesting Stone Age sailors may have been more advanced than they thought. The Ryukyu island chain in Japan was first populated between 30,000 and 40,000 years ago, and many archaeologists believe that these early settlers would have reached the islands on bamboo rafts, which can be made from local materials with Palaeolithic technology. However, when a team working with local Amis people created a replica raft, they were unable to complete a journey from Taiwan to a nearby island. Despite having a crew of professional and semi-professional sea kayakers, the bamboo vessel couldn’t make headway between islands due to the Kuroshio ocean current – one of the strongest currents in the world – and the attempt was abandoned after 14 hours. The researchers now believe that a more advanced log craft must have been used – something they tested earlier this year. Paddle over to that research in Antiquity.

[Jingle]

Host: Benjamin Thompson

Well, next up on the show then, Nick, you were away last week in California.

Interviewer: Nick Howe

That’s right, I was there for a conference organised by the Acoustical Society of America, which was rammed with amazing sound-related science.

Host: Benjamin Thompson

What then, if you’ll excuse the terrible joke, did you hear when you were there?

Interviewer: Nick Howe

Well, there was so much there. It was an enormous conference and there were a whole range of different talks and plenty of interesting stuff, but there were a couple of things that did catch my attention. One of them was all about ukuleles and I’m going to play a couple of sounds for you and I just want to know what you think to start off with.

Host: Benjamin Thompson

Right, go on then. What have we got first?

Interviewer: Nick Howe

Well, here we’ve go. This is the first sound.

Ukulele sound

Host: Benjamin Thompson

Well, I’m no expert. That does sound like a ukulele I think.

Interviewer: Nick Howe

Well observed, but how does it compare to this second sound?

Ukulele sound

Host: Benjamin Thompson

Well, I would say I think the first one seems a little bit brighter maybe. It seems a little bit maybe not louder but just it has a bit more about it, a bit more personality maybe.

Interviewer: Nick Howe

Yeah, I think that’s a fair assessment. I mean, do you have any inkling of what might be the difference between these two ukuleles?

Host: Benjamin Thompson

I mean, I’m not much of a musician so I don’t think it’s about the tuning but, to be honest with you, you’ve stumped me. I don’t know – what is the difference between those two ukulele notes?

Interviewer: Nick Howe

Well, believe it or not, the second one was actually 3D-printed, so despite the fact that these are being plucked in exactly the same way, there is a different sound to it.

Host: Benjamin Thompson

And what is it about 3D printing then that’s led to this difference?

Interviewer: Nick Howe

So, according to the author who presented this talk, it’s to do with the materials and how they absorb sound. So, when you play a ukulele, part of the soundwaves gets absorbed by the materials that it’s made from, and the wooden one is a lot more efficient so less of that sound is absorbed so you get that louder, brighter tone, whereas the 3D-printed one, it’s actually absorbing more of the soundwaves as it’s played.

Host: Benjamin Thompson

Well, does that mean the end of the road then for 3D-printed instruments if they maybe don’t produce sound that people like quite as much?

Interviewer: Nick Howe

Well, it depends on how you look at it because you could want different sort of sound styles for different types of music. Maybe you want like that quieter, softer tone that comes from the 3D-printed one for a certain type of music. And also, by 3D printing things you can make them a lot more cheaply so it could be a way to more readily produce instruments for people to use.

Host: Benjamin Thompson

Right, well so far so good then. What else did you come across then at the conference?

Interviewer: Nick Howe

So, there was another talk that was presenting basically a new way to treat glioblastomas, which are a type of brain tumour. I thought this was interesting because this is something that’s notoriously hard to get treatments for because the blood-brain barrier actually prevents drugs getting into the brain and getting to the tumours where it’s needed, but rather than having me explain how it worked, let’s let Costas Arvanitis, who presented the talk, tell you all about it.

Interviewee: Costas Arvanitis

There are three different components in the whole strategy. First, is the ultrasound, which is a focused beam that allows us to focus ultrasound energy in a very small region of the brain and this region is the tumour region. Secondly, at the same time that we apply the small ultrasound pulses, we inject microbubbles. So, the microbubbles, in the presence of the pressure wave, they start to vibrate, and this vibration essentially interacts with the endothelial wall and the blood-brain barrier, as it is called in the brain, and it’s not well understood but it has been quite well established that, essentially, it does increase the permeability of the vessels. So, after we have applied the ultrasound in combination with microbubbles, then we inject the drug. So, the drug now, because the blood-brain barrier has been opened, the drugs can now penetrate, can now go from the blood into the tumour in the regions and in the region that we target with the ultrasound.

Host: Benjamin Thompson

Wow, so this is kind of a super precise way then of targeting where drugs can get into the brain.

Interviewer: Nick Howe

Yeah exactly, and that’s the hope – that it will be able to be used in such a way that will reduce toxicity to other areas of the brain.

Host: Benjamin Thompson

Right, and is this being used then? Is this being rolled out in treatment centres?

Interviewer: Nick Howe

Well, what I should say is this study is in mice, but they are in the first stage of clinical trials and they’re getting positive results at the moment, but we’ll have to see what happens with those.

Host: Benjamin Thompson

Right, well, so far so good. What else did you come across then at the conference?

Interviewer: Nick Howe

I went to an interesting talk about how to use sound in climate change research. Now, I personally think of climate change as something that you can see rather than hear but apparently, there’s a lot you can do with audio in climate change research. For instance, you can use soundwaves to work out how much the ocean is warming by.

Host: Benjamin Thompson

Right, and how on Earth do you go about doing that?

Interviewer: Nick Howe

So, if you have like a speaker and a microphone a set distance apart, you can measure how long the sound takes to travel from one to the other and because it’s well known that it moves at different rates depending on the temperature of the water, you can use that to work out how warm or how cold the ocean is.

Host: Benjamin Thompson

That’s very clever.

Interviewer: Nick Howe

Yeah, and that’s not the only thing. In the talk as well they went on to say how they could use sound to actually measure carbon in the environment. And I spoke to one of the researchers involved in this, Gabe Venegas, and he’s been working out how to make a tool to do exactly this.

Interviewee: Gabe Venegas

We have a lot of capabilities to measure acoustic properties of sediments, and it’s been done for a really long time but it hasn’t really been mapped over to organic carbon and that’s something that one of our findings has shown. In one seagrass meadow that we looked at, there was a really good correlation with the acoustic properties and how much organic carbon was stored, so if we can measure these acoustic properties, then we can have a pretty good understanding or a pretty good estimate of how much organic carbon there was at that measurement instantaneously. So, that is the goal, the application in the end is to have this sort of magic, ultrasonic probe that you can stick in the ground in a seagrass meadow or a mangrove or a salt marsh and it can essentially tell you or give you a good estimate of how much organic carbon there is instantaneously.

Host: Benjamin Thompson

Crikey, and how will this help then overall, knowing how much carbon is in an environment?

Interviewer: Nick HoweSo, this is a really useful thing for ecologists and economists because they can use it to work out carbon budgets for an environment. So, for example, if you wanted to protect mangroves, say, a reason that you could suggest to do that is because it stores a lot of carbon and you could use this probe to show that and show how much carbon is stored in the environment.

Host: Benjamin Thompson

Well, you’ve covered a lot of bases there, Nick. Is there one other sound maybe that sort of sums up your trip to this conference?

Interviewer: Nick Howe

Well, there was one last thing I wanted to share with you, and we’re all familiar with the table of elements – all the different things that make up the entire Universe – and each one of those elements, when they get excited, they emit different wavelengths of light, and you can use those to make a profile of sound, and someone has just done that, so would you like to hear helium?

Host: Benjamin Thompson

Absolutely, I would, yes.

Helium sound

Host: Benjamin Thompson

Helium’s theme tune needs a little bit of work I think.

Interviewer: Nick Howe

Yeah, I mean people have used a bit of artistic license to make these into more musical-type sounds and there are some interesting things out there and there was loads of interesting stuff at this conference and there’s some stuff that I’ll definitely be working on and you might hear in the next few months.

Interviewer: Benjamin Thompson

Finally then on the show, it’s time for the News Chat and in fact, the penultimate News Chat of the year, and I’m joined here in the studio by Nisha Gaind, Nature’s European Bureau Chief. Nisha, hi.

Interviewee: Nisha Gaind

Hello.

Interviewer: Benjamin Thompson

Thank you so much for joining me today. We’ve got two stories, and this first one, well, it’s a bit different to what you and I might normally talk about on the Nature Podcast, and well, it’s about a big idea about humanity’s transition to modernity and maybe a challenge to this big idea.

Interviewee: Nisha Gaind

Yeah, that’s right. It’s a bit different. It’s something in the humanities, but it’s a really sort of delicious story that gets into this big, historical concept called the Axial Age, and this is something that has been knocking around in scholarly circles and in historical circles for about 200 years, and it’s this idea that in the first millennium BC, and specifically between about 800 and 200 BC, there was this sort of simultaneous shift to what we’re generally terming modernity, this kind of spiritual, psychological shift that happened throughout the world, and it’s proposed that this happened independently in particular societies and then spread throughout the world, but that is something that, as you say, is now being challenged.

Interviewer: Benjamin Thompson

Well, we are a science podcast here, Nisha, of course – how is science being used to challenge this long-standing idea?

Interviewee: Nisha Gaind

The research that has been done here, the research that we’re reporting, is by a team of scholars who has used this kind of big data approach to history. They’ve scoured a huge amount of historical data in a database and through that, they have formed the conclusion that, in fact, this Axial Age that happened over this narrow timespan of a few hundred years was not, in fact, that at all, and they proffer that the Axial Age didn’t really happen at all or certainly didn’t happen as it was previously suggested and, in fact, it was a much messier transition. Sometimes societies shifted to modernity much earlier, sometimes much later, and it happened outside of these five particular societies that had been suggested before – places like Greece, Israel, Palestine, Iran, India and China – so what they’re saying is that things happened all over the world at many different times.

Interviewer: Benjamin Thompson

How did the researchers involved then in this new work sort of come up with their idea? What was the data they were looking at to decide what was modernity and what wasn’t?

Interviewee: Nisha Gaind

A lot of this hinges on definitions, and what these researchers did was to draw up a list of twelve measures that they say scholars widely agree on that are examples of Axial transformation, and that’s another way of showing when there was this pivotal shift in a society. Examples of these include the emergence of a formal legal code in a society, the belief in an all-knowing supernatural being, and that would differ from, for example, a kind of mortal, divine ruler in these more arcane societies. And another one would be the existence of bureaucrats who were employed to hold rulers to account in a society. So, they used things like this and then they searched for them in several civilisations around the world, not just these five that had originally been proposed.

Interviewer: Benjamin Thompson

And they found, I guess, then that these aspects of modernity were found wider than expected.

Interviewee: Nisha Gaind

Yes, that’s right. They were found across a really wide spectrum of times, and certainly wider than this original suggestion of the first millennium BC. In one example, they found the rule of law being applied in the second millennium BC in Anatolia – that’s sort of modern-day Turkey. In another example, China, these scholars suggest, shifted to modernity much later, perhaps after 200 BC. So, there’s a lot of variety here.

Interviewer: Benjamin Thompson

Yeah, and a lot of data being looked at. Has this kind of put to bed the argument about when modernity happened in different parts of the world, or is this really just the beginning?

Interviewee: Nisha Gaind

Well, it would be a very rare instance for a question such as this to be settled by just one study, and indeed, this is a topic that is fraught with all sorts of exciting discussion in the historical arena, and there are, of course, scholars who disagree with this study. They say that the concept of Axial Age was thrown out ages ago and it’s perhaps important to note that this hasn’t been peer reviewed. And there are others that say, in fact, the argument has moved on. It’s not so much about time and place anymore. It’s more about the causal mechanisms of these shifts that we have seen around the world. So, there are many more questions to answer here and there are likely to be many more studies that use this big data approach to history.

Interviewer: Benjamin Thompson

Well, the news article mentioned claims that humanity might be in a second Axial Age brought about by things like technological advances and so on, and our next story is very much technology-based and it’s about exoplanets in particular, something we love talking about here on the Nature Podcast, but rather than just searching for new exoplanets, there’s a satellite going up which is going to do something rather different.

Interviewee: Nisha Gaind

Yeah, that’s right. It has been a big year for exoplanets. As you might remember, there was a Nobel Prize awarded for the discovery of a particular type of exoplanet and now we have got a new mission that is going to study exoplanets in detail, and that’s exciting because we haven’t really had one of those before. All of the previous satellites that have been dedicated to exoplanets have been aimed at finding more of them rather than finding out more about them.

Interviewer: Benjamin Thompson

And what can you tell me then about this new mission?

Interviewee: Nisha Gaind

It’s called CHEOPS and that’s short for Characterising Exoplanet Satellite, and it’s built by the European Space Agency. It will be launching into orbit later this month, and once it’s there and once it begins its scientific mission next April, it will be aiming to study about 300-500 exoplanets and it will be hoping to answer some of these really key questions that we now have and that’s how do exoplanets form and how do they evolve?

Interviewer: Benjamin Thompson

So, is this the start then of a shift from just sort of searching around for these things to knowing more about them?

Interviewee: Nisha Gaind

Yes, exactly, and there’s a lot of excitement in the astronomical community because exoplanets have become such a hot field in astrophysics, and now, discoveries have been coming thick and fast and now we’re really seeing this shift towards finding out more about them, and CHEOPS is just the first of a few new missions that will be dedicated to doing that. There will be another European Space Agency mission launching in the 2020s and that’s called ARIEL and it will aim to find out more about the atmospheres of exoplanets and we also mustn’t forget that the James Webb Space Telescope – that’s NASA’s next mega space telescope and the follow up to the Hubble Telescope – will be also able to tell us more about exoplanets.

Interviewer: Benjamin Thompson

In our news story, there’s a few of these planets listed and they seem quite wild and weird in terms of their makeup.

Interviewee: Nisha Gaind

Yeah, that’s what’s so exciting about reading about these missions is that we get to learn all of these incredible details about these planets that are parsecs away. There are lots of different types of planets that CHEOPS will try to study and one of them is this really hot planet. It’s got this dayside temperature of more than 4,000 degrees and one astronomer comments that that’s actually hotter than a cool star. So, there’s a huge range of these planets from cool to hot, from Earth-sized to much larger, that CHEOPS will be peering at with its camera.

Interviewer: Benjamin Thompson

Well, we shall have to get you back on, Nisha, when it’s had a little look, to find out some more about these exoplanets. In the meantime, thank you so much for joining me.

Interviewee: Nisha Gaind

Thank you.

Interviewer: Benjamin Thompson

And listeners, to read even more about those exoplanets and about the Axial Age research, head over to nature.com/news.

Host: Nick Howe

That’s all for this week’s show. Next week, it’s our last regular podcast of the year and we’ll be back with our festive spectacular. Long-time listeners will know exactly what we’re talking about, but for those of you who aren’t familiar, we’ll have some holiday fun and games.

Host: Benjamin Thompson

And just before we go this week, there’s time to tell you about a little experiment we’ve got coming up. We’re piloting an audio long-form podcast, where we’ll be reading out one of our recent feature articles about coral. Look out for that in your podcast feed next week. I’m Benjamin Thompson.

Host: Nick Howe

And I’m Nick Howe. See you next time.