Nature Podcast

This is a transcript of the 12th June edition of the weekly Nature Podcast. Audio files for the current show and archive episodes can be accessed from the Nature Podcast index page (http://www.nature.com/nature/podcast), which also contains details on how to subscribe to the Nature Podcast for FREE, and has troubleshooting top-tips. Send us your feedback to podcast@nature.com.

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Kerri Smith: Coming up this week, a study of natural undersea gas vents warns of the consequences of ocean acidification.

Jason M. Hall-Spencer: You roll over to the start of the boat and you plunge into what seems to be champagne, it is full of bubbles and that champagne is acidic and as we swim through the champagne field, you find organisms dropping out of the ecosystem.

Michael Hopkin: Experimental psychologist and author Steven Pinker joined us in the pod to talk about language and human nature, including why swear words are allowed to flout the laws of grammar.

Steven Pinker: You have a strange phenomenon of word substituting for each other simply because of their taboo status, running roughshod over distinctions of grammar and meaning.

Michael Hopkin: This is the Nature podcast, I'm Mike Hopkin.

Kerri Smith: And I'm Kerri Smith. First this week, the stunning illustrations of brain activity created by the scanning technique fMRI can reveal much about how the brain works from how it processes the visual world to how we interact socially. They might look pretty, but how much do we really know about what these images show us. According to an article by Nikos Logothetis, Director of the Max Planck Institute for Biological Cybernetics in Germany, the answer is startling a little. Nature 453, 869–878 (12 June 2008)

Nikos K. Logothetis: We've known for over 100 years that there is a very interesting and actually if not stunning coupling between increases in neural activity and increases in energy metabolism which is kind of obvious, because you work more, you want to have more food and very simple. These kind of increase in the metabolism is associated very tightly with an increase in the flow of blood locally. It is very regional. If one area of the brain is activated that particular area has higher energy metabolism and this higher energy metabolism requires more blood flow and more blood flow means more oxygen. fMRI is sensitive to oxygenation changes during activation, so people discovered that, different people, and they assumed that if you see an increase in the fMRI signal in the brain in that particular location, where you see the signal increase there is an increase of the metabolism and the increase of the metabolism is due to an increase in neural activity.

Kerri Smith: And people use this assumption and this principle is very prevalent technique now in neuroscience to try and pinpoint which areas of the brain are doing what during experiments.

Nikos K. Logothetis: Exactly, so what you're asking right now, it is basically the heart of the question, so I was trying to answer with a review, because you say there is an increase of neural activity somewhere, but it is not clear exactly what this neural activity increase might be. You could have a neural activity increase that is related to something that the subject is doing, let's say movement or you could have an increase in neural activity because you are presenting a sensory stimulus if you touch the subject's hand or you present a visual stimulus or you start basically playing a musical piece and the brain will react to that. We have known that for years from physiology and from everything and if you get an fMRI signal increase as a response to that particular sensory stimulation or to a motor act, you say okay, now I see that that particular brain area is involved in processing signals related to that sensory stimulus or to that motor act.

Kerri Smith: But I suppose that's about as much as we can say, isn't it? Because what if the involvement was actually an inhibition by these neurons of activation, that would still require some energy for them to do that, but they're doing an opposite thing to what we are seeing.

Nikos K. Logothetis: That is totally true. You may have different types of neural activity increases that are not necessarily related to that particular sensory stimulus or to the motor act. It is very difficult to dissect these cases from one another for the simple reason that the fMRI signal is extremely sensitive to the total amount of neural activation. Whether this activation is specific or not specific. If you get more neurons involved in something, you have more energy consumption and you have more fMRI signal and in some cases more neurons is coming not only because of sensory stimulation but because of the change in the state of the subject. Whether this is arousal, attention, or other things and those things cannot be easily dissociated. You have to use extremely clever experimental designs and even if you do multiple experiments, you may still not be able to say, "now I know for sure, this particular area is doing this particular thing." The only way you can achieve that is if you manage to have parallel experimentation with methods that are less so to speak sensitive to this kind of mass activation.

Kerri Smith: So this is one of the main implications then that we need to be using this technique in conjunction with others?

Nikos K. Logothetis: Exactly, you may feel free to use the technique and throw all conclusions you want with all the risks entail, but you are not likely to be right. You can say anything you want, and people unfortunately do say whatever they want. People have sometimes a tendency to throw grandeurs, conclusions, and I see that and I do that but it is not so easy. I am not by any means bad mouthing the MRI technology. In fact I think it is extremely useful and it can be used as a tool to formulate very very intelligent and experiment-based hypothesis to say "well I see these, I see these and I see these.... and if I changed the conditions then I see slight modifications of these and these and these and now it's about time to figure out how I can understand what exactly is happening.

Kerri Smith: So, you just need to not get too carried away.

Nikos K. Logothetis: Yes, this technique is one instrument of a very grand orchestra and you cannot just use it to play the whole symphony, it is impossible.

Michael Hopkin: Nikos Logothetis. We are off now to Italy, well rather just off the Italian coast where a series of underwater vents that bubble out carbon dioxide are being used as a test bed for theories of how global warming will affect the oceans. Geoff Brumfiel reports.

Geoff Brumfiel: You're probably aware that carbon dioxide is changing our atmosphere, but it is changing the seas as well. Oceans absorb huge amounts of man-made CO2 every year and in doing so, they become gradually more acidic. The acidification could have a big effect on the underwater ecosystem, but nobody knows exactly what will happen. Well it turns out that there may be some clues lurking around volcanic vents off the coast of Italy. I spoke to Nature author, Jason Hall-Spencer at the University of Plymouth to learn more. Nature advance online publication (8 June 2008)

Jason M. Hall-Spencer: Everybody knows that as you increase carbon dioxide levels in the atmosphere it causes the green-house effect and warms up the planet, but less people know that carbon dioxide is dissolving in the ocean and as it does so, it lowers the pH, because the amount of H+ ions increase as the CO2 is dissolved. We have pumped so much CO2 into the atmosphere that we cannot stop this process of the equilibration of atmospheric CO2 with the sea, then leads to lowering of pH.

Geoff Brumfiel: And what if people have been concerned about in terms of how it is going to affect the ocean ecosystems.

Jason M. Hall-Spencer: Well, mainly up-to-date, people have been worried that as you lower the pH, you actually lower the amounts of calcite and aragonite which in the water and it's calcite and aragonite that most calcifying organisms use to build their shells and there's lot of other things that live in the sea, of course calcified shells, obviously corals do, but there are other things as well, like these coccolithophores that are in the surface of the sea, they are major part of food web and that might be that they can't form their shells in the future. The theories as of the moment is whether the increased carbon is going to fertilize their growth and so they actually produce more than calcium or whether its, I am going to dissolve them and there is papers in Nature and Science just going back and forth trying to work out whether this is happening or not, but the trouble with those studies is they are done in mesocosms which are large aquaria and cannot replicate what happens on a large scale and that's where my study and my colleagues have made progress because we are looking at areas that are naturally acidified by volcanic vents that had been in place for millennia and so the organisms that are living in these areas are actually having to put up with lowered pH over their entire lifetimes.

Geoff Brumfiel: Where are these vents that you're looking at?

Jason M. Hall-Spencer: The main ones are on the area off the Bay of Naples in Italy where you've got Mount Vesuvius one of your most active and largest volcanoes and further down the coast of Italy you've got Mount Etna which is another huge volcano and the reason why this area is so volcanic is because Africa is tectonically moving into Europe and this movement is driving up the Alps, but as it does so, it is pushing old chalk which was made by the coccolithophores in prehistoric times. The coccolithophores settled on the seabed form chalky deposits and now those chalky deposits are being pushed into the magma of these hot spots, these volcanic areas. As that happens it drives off carbon dioxide that is emitted like a Jacuzzi of gas coming out of the seabed.

Geoff Brumfiel: So, how do you actually get to these sites, and how do you measure the biodiversity there?

Jason M. Hall-Spencer: Well, there is a marine biology station near to some of these vent systems and they've currently been providing facilities like boats and divers first to conduct these studies and what you do, is you roll over to the start of the boat and you plunge into what seems to be champagne, because it is full of bubbles and that champagne is acidic and as we swim through the champagne field, you find organisms dropping out of the ecosystem as they get exposed to lower and lower levels of pH. So, as you snorkel or dive through the zones, it's like looking into the future of the changes of the sea over the course of the century and the next.

Geoff Brumfiel: So, what did you find in these ecosystems.

Jason M. Hall-Spencer: Well, it is quite worrying because these experiments that have led to the study that have been based in test tubes in an aquaria are all proving to be pretty much spot on in terms of the major ecosystem effects of ocean acidification, what you get as you go on a gradient of pH through these vent systems is a shift from communities that are dominated by calcareous organisms into communities that are not. So, for example, the corals just disappear below about pH 7.8 or 7.7, they cannot form their skeletons and as they disappear, they are replaced by other types of organism, so the Maldives for example which is protected by a coral reef from erosion in the future, they might disappear, because of the glue that holds them each together and the reason cells will dissolve. As you go into the vent field you do find there are winners, things that benefit from the increased carbon dioxide. Most notably there's lush growths of sea grasses waving in the Jacuzzi of bubbles, but you also get nuisance algae, invasive alien species of algae that take over the communities and quite buried that they are going to radically change the marine shallow habitats around the coasts of the planet.

Geoff Brumfiel: Over what time scale are these changes going to take place.

Jason M. Hall-Spencer: Well, current projections which are based on and carrying on burning fossil fuels, they say that by the 2100 there will be a reduction in pH of the oceans by about 0.4 units or 0.5 units and when we look at the areas in the vent fields that have been reduced, the mean pH has been reduced by 0.4 or 0.5 units, you see radical changes in the marine communities, mainly a reduction in biodiversity and a reduction in calcified organisms. So by 2100, if these volcanic vents represent the situation accurately then it is a major worry because they show that these corals and other organisms disappear at those levels of pH.

Michael Hopkin: Jason Hall-Spencer there. Coming up shortly, we will be talking about the big new trend in biomed called translational research and hearing how it is more than just a buzz word.

Kerri Smith: But first do humans and animals react to risk differently. Charlotte Stoddart took the chance to find out.

Charlotte Stoddart: Buying insurance is an example of risk averse behaviour. We are protecting ourselves against an unlikely, but unwanted outcome. But when we play the lottery we risk seeking, we buy a ticket even though there is an extremely small probability that we will win the jackpot. A team of scientists in Israel have been looking into this kind of behaviour and trying to figure out why risk experiments on people and animals give conflicting results. They show that how human subjects and honeybees respond to risky decision making depends on how the information is presented. Here is team member Ido Erev. Nature 453, 917–920 (12 June 2008)

Ido Erev: Most studies of human decision making focus on decisions from description and typical study subjects are basically said, what do you prefer, 9 dollars with certainty or 10 dollars with probability, 0.90 otherwise. Okay, so the problem is described towards the subject and the main result of this study that people exhibit high sensitivity to the rare events. So in this example, they preferred a 9 with certainty, so in this case, they behave as if they are risk averse. In decision from experience, the subjects are not told what the gambles are and in the typical experiment they see a computer screen with two unmarked key and they have to select between the 2 prospects. One prospect for example gives them 9 every time they select it and the other one gives them 10 in 90% of the time and zero in the remaining 10%. And here we get the reverse pattern, now they tend to prefer the gamble that gives 10, 90% of the time.

Charlotte Stoddart: Now before your study, people had looked at decision making from experience both in humans and in other animals, but the results were conflicting.

Ido Erev: Yes. In our studies, we find that when people have to rely on experience they underweigh rare events. And in some cases they exhibit risk seeking. On the other hand the previous research on animal trace behaviour appear to suggest that animals are risk averse. So, the question was why experience appear to have different effect on human and on animal.

Charlotte Stoddart: And you hypothesized then that these conflicting results were due to different experimental conditions, so could you start off by explaining the set up of the original experiment done on humans.

Ido Erev: Well, the typical experiment with humans, the outcome are numbers. So you have two unmarked keys on the computer screen, but each time you select one, you get a payoff which is a number.

Charlotte Stoddart: But in the new experiments that you have done, the payout was not represented as numbers, it was represented as red dots instead.

Ido Erev: Exactly, we hypothesized that maybe the apparent difference between human and animal may be related to the precision of the outcome. So in a typical experiment with animal, they get food as a reward and we thought may be it's hard for the animal to discriminate between 9 cups of sweet water or 10 cups and may be for that reason, they don't exhibit the same behaviour and basically prefers a 9 with certainty because it is hard to discriminate between the 9 and the 10, but they can discriminate between the nine and the 0. To test this hypothesis, is one experiment with human in which we did not present the outcome numerically, but we showed them as number of dots and each dot was worth some points, it was either 30 dots or 40 dots on a computer screen and it was hard to discriminate and now we find people behave like animal and always behave as they are risk averse.

Charlotte Stoddart: Do you have any idea what's going on in the brain, when we make this choice between a more certain payout or the more risky option?

Ido Erev: Well, our hypothesis is that in those situation, people and animals has to rely on their experience. So, they behave as if they recall a small set of experience in similar situation and then select the alternative that gave better outcome in those similar situations. So, it is a very reasonable model, but it can lead to deviation from optimal choice and the deviation occurs because in a small set of samples, rare event are less likely to occur.

Charlotte Stoddart: What does this tell us then about real life?

Ido Erev: It was, I think the one interesting application is about the value of enforcing safety rules. So basically, our results suggest that when people think about, you know, safety devices whether they should behave safely or drive safely, they actually want to behave safely. When they plan, they make decisions basically based on descriptions. So they think about it and they buy safety devices. However, in ongoing decision, when they have little time to think about the possible outcome, then they behave as if they rely on small samples and in small samples this rare negative outcome like accidents are less likely to be considered and then they take too much risk. So, one implication of that which we have implemented in intervention studies in factories is that you really have to enforce safety rules.

Kerri Smith: Ido Erev, currently on sabbatical at Harvard University talking to Charlotte.

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Michael Hopkin: In just a moment we will be hearing from Steven Pinker on taboos, time and why we never say what we mean. But first, if you work in BioMed you already know the term translational research, but what is it. Well, it is designed to be a more effective way to convert basic science into more of the things that really matter to patients such as new therapies. The new approach is the subject of a special package in this week's issue of Nature and we are joined on the line from New York by Features editor Helen Pearson who has put the package together. Published online (11 June 2008)

Michael Hopkin: Hi Helen.

Helen Pearson: Hi Mike.

Michael Hopkin: So, I suppose the only first question is what is translational research?

Helen Pearson: Well, that is a good first question because if you've asked 10 people that question, you would probably get 10 completely different answers. It's a fairly new term actually only came to be commonly used after around 2000, but generally in the issue, we have taken it to be what is the most relevant to our readers. So, it is taking discoveries which have been made in basic biomedical science such as new drug targets and it is ensuring that they end up actually helping patients. What it doesn't mean is the discoveries end up stitching on shells or just in the pages of a journal like Nature., So often translational research is taken to be synonymous with bench to bed size research as if you are going to take these basic biomedical discoveries and feed them into this pipeline or black box and then out the end will pop this perfect drug, but what most people are saying now is, it is much more cyclic process. So that when things, for example, are tested in humans that is actually an experiment in itself and you need to take the results of that experiment. Even if it is a failed clinical trial and learn from them and feed those results back to the bench.

Michael Hopkin: So, has that traditionally been a big disconnection between basic research and applications, and is this a way of trying to tackle that?

Helen Pearson: Historically, there hasn't really been a disconnect. So I think if you went back 30 or 40 years, you would find that basic research and medicine really went hand in hand and a lot of people were trained in both disciplines but the reason that this has become an issue is that biomedical research has changed massively in the last 10 or 20 years. So it used to be all about one gene, one protein, one molecule and now it is all about all genes, all proteins, all molecules all of the time. Just take the human genome project, I mean just say we have a list of virtually every drug target thought to exist, it has almost become overwhelming. So, while there has been this explosion in the quantity of information that is coming out, the problem is that there has not been this equal explosion or increase in the ways to carry that basic information through into the clinic.

Michael Hopkin: Is there a right and a wrong way to try and do translational research without it becoming all too confusing?

Helen Pearson: I don't think we can say at this stage there is a right and a wrong way because it is a fairly new effort. Many many institutions are trying to put in place ways to do it. For example the National Institutes of Health, one of the focuses under director Elias Zerhouni has been to tackle translational research and they are investing 500 million a year at the moment to set up centres for translation across the US and lots of people are watching that effort with a lot of interest and within each of those centres they are going about in different ways but generally involves training courses, for people who are comfortable with basic research and with clinical research. So, it is often about setting up infrastructure, but to say one way is better than the next, I think it is too premature at this stage.

Michael Hopkin: So you mention basic research there, if your average basic researcher going to have to change their approach in order to preserve their funding and our basic researchers are too resentful about this new movement.

Helen Pearson: I think there is a nervousness amongst basic researchers that the new emphasis on translation research means the pendulum has swung too far towards application and away from what they like to do. I am not convinced there is much foundation to that. I think that a lot of these efforts are adding to, for example, the money which is already going into basic research and for example, this effort by the NIH is still 1 to 2% of the budget which is going on translation. So, yes there is that feeling about apprehension, but I don't think the message that I heard from their people I interviewed is that we should be scaling back on basic research, most people still recognize that it is the serendipitous discovery that come from blue-sky research which end up being the best to translate and so we need to still support that and that's what Zerhouni would say too.

Michael Hopkin: So, how will we actually know whether or not translational research is working in the years to come or we are going to start saying lots of BioMed researchers becoming millionaires with their own spin-off companies.

Helen Pearson: It's very difficult to measure. It's one of the questions which people who are dealing with translation research are scratching their heads over. So, that is partly because drug developments and diagnostic developments is a really long process, it takes 10 or 20 years and most things that enter the process will end up failing at some point. So lots of organizations are saying how we are going to measure our success and they might end up counting the number of clinical trials they are doing or the amount of intellectual property they have generated on the number of people they have trained, but I think it is almost a question we need to come back to in 5 or 10 years time and then if the number of new drugs and products hasn't gone up then we need to question whether this focus on translation is working.

Kerri Smith: That was Nature's Helen Pearson. Finally this week, scientists have found many ways to study human nature - through our DNA or our ecology - but experimental psychologist, Steven Pinker has chosen language as his window into human nature. In his latest book, The Stuff of Thought, which was published in paperback last week, he explains what our words can reveal about how we think. He joined me in the studio earlier this week and I asked him about what kinds of ideas about the world are reflected in language. And I warn you now there is some swearing in this.

Steven Pinker: If you look at the kinds of concepts that seem to keep reappearing in language after language and in construction after construction, you find that pretty soon you start to turn back on yourself and the same ones keep popping up and leading to important grammatical distinctions. The concept of causation, the concept of intention, the difference between a means and an end, the concept of an object, a conception of time has dichotomized or trichotomized between the present, the moment of consciousness and an interval before and an interval after it. The particular constructions in a language obviously vary, the particular rules that determine which words you can or can't use vary, but they fall into universal patterns and they have been documented in hundreds and hundreds of languages.

Kerri Smith: Will challenges like quantum physics for example at the boundaries of science then ever really make sense through the lens of language?

Steven Pinker: Well, because language is a combinatorial system that is we don't have a finite list of messages that we pick from a list, but we have got a grammar that allows us to combine nouns and verbs in an explosive number of combinations. Also language has in it, metaphor, not metaphor in a sense of literary ornament but metaphor in the sense of allowing us to take an idea that works for one system and leech out all of the contents specific to that system and apply it to a second system. Taking concrete language, raising the concrete bits and applying that skeleton to more abstract domains that we use in science all the time and I suggest in the book that the combination of metaphor and analogy with the combinatorial power of language is what allows language to express thoughts such as scientific thoughts that can be quiet alien to our instinctive way of analyzing the world.

Kerri Smith: There is a much publicized chapter in the book about swearing in all its ungrammatical glory, so where exactly do these words come from that we now think as swear words and why do they have the potency that they do?

Steven Pinker: One common denominator of the taboo words across different languages is they come from domains of strong negative emotions. There are taboo terms in many languages for deities and supernatural entities and their various relics and body parts like our own hell, damn, and Jesus Christ which involve the emotion of awe and fear of the power of deities. There are many taboo terms for bodily secretions in the organs that produce them and that evokes the emotion of discussed, there are many sexual implications which evoke the emotion of revulsion at sexual depravity, but in all cases, there is a strong negative emotion and that is not enough to make a word taboo. In addition, there has to be the recognition that the negative concept is being brought up precisely in order to offend you, and that is the difference between a taboo term like shit and the polite euphemism faeces.

Kerri Smith: Why don't they obey grammatical laws like other words then, why is it okay to say, I don't give a bleep or it is bleeping brilliant, I mean those don't semantically mean anything, the words don't add anything to those sentences and I couldn't intersperse other words that mean a similar thing into those sentences and mean the same thing.

Steven Pinker: That's why you could even say things like cappu-fucking-ccino or hot-fucking-dog which will violate all the rules of English and also the semantics are nonsensical. Drown the fucking cat does not mean drown the cat that is fucking, a most likely source is that words can substitute for one another when they have the same emotional force even if they have different grammatical and semantic properties and I suspect that most of the very strange epithets like close the fucking door which doesn't seem to make any sense evolve from religious epithets that lost their force as religion came to play a smaller role in our emotional lives. So, close the goddamn door, does make sense, if something is damned than it is pitiable, execrable of no earthly use. As damn started to lose its sting but there is still that slot in the sentence you used fuck to substitute for it, so you've a strange phenomena which I don't think you see anywhere else in the language of word substituting for each other simply because of their taboo status running roughshod over distinctions of grammar and meaning.

Kerri Smith: I was going to conclude by asking about the flip side of swearing and cursing and how that have to be politeness, the reason why I would say, I don't suppose you'd like to say here's Professor Pinker or supposed to sit there, Steve. We have straight forward words to straight forward things and why don't we just say what we mean a bit more often?

Steven Pinker: I think it's because humans are very touchy about their relationships unlike other animals which do with each other in a very circumscribed number of ways. We can flip back and forth between the kind of distribution of resources that we have between a pair of people. So we have dominance, you give me what I want, we have reciprocity, "you scratch my back, I will scratch yours", we have mutualism or communality "what's mine is thine, what's thine is mine" but you got to know which one is in force at a given time, because if you mix them up you could do something seriously wrong. When we use language sometimes the actual proposition that we use changes the relationship and if you are uncertain that the other person is ready to do that then you are taking a risk that if they are not willing to go along with it, your relationship is forever changed as in sexual come-on, you can no longer pretend that your colleagues or friends if the sexual proposition has been made in the open. On the other hand if the sexual come-on is veiled then the recipient can choose to pretend that it was a literal request to see etchings or to have coffee, turn it down without both parties having to acknowledge that they have switched from one relationship type to another.

Kerri Smith: That was Steven Pinker and for more from him on concepts, courtesy, and cursing you can listen to the full version of that interview available free at http://www.nature.com/nature/podcast or if you are a subscriber you will have had it delivered already...Magic.....

Michael Hopkin: And if you want even more thought provoking stuff about our brains then why not have a listen to neuropod, Nature's neuroscience podcast available from http://www.nature.com/podcasts. That's all from us this week. I'm Mike Hopkin.

Kerri Smith: And I'm Kerri Smith. Thanks for listening.

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