OCD, Obesity, and Dark Comets

Introduction

0:00This BBC podcast is supported by ads outside the UK. BBC Sounds. Music, radio, podcasts.

0:10Hello, welcome to this week's 5 Live Science. I'm Chris Smith from The Naked Scientist. And coming up, Operation Ouchies' Chris Van Tiliken tells us why he's tackling obesity in his Christmas lectures this year. Also, how radioactivity encased in diamonds can make safe batteries, one spin-off of which is that they can potentially last for thousands of years. How's that for timekeeping? They weren't alien spacecraft after all, but what are the dark comments that space scientists are now documenting? And a bit later on...

OCD and Hygiene

0:41The classical example really is germs, fear of infection. And so this leads to excessive hygienic behaviours, washing your hands so often with bleach that you actually cause damage. Then clearly it's a compulsive behaviours. We put OCD, that's obsessive-compulsive disorder, under the microscope to find out why some people are plagued by horrible thoughts that make them repetitively do what they often know are fruitless things. Why? And how can we help them?

1:12The Naked Scientists on 5 Live.

UK's Chief Medical Officer

1:16First this week, the UK's Chief Medical Officer, Chris Whitty, has used his annual report to bear down heavily on obesity. He's advocating for a stiff levy on junk food to tackle both childhood obesity and, he says, worklessness. The move, which has been dubbed a fat tax by the British press, comes as the broadcaster, doctor and author Chris Van Tiliken, prepares to deliver the 2024 Royal Institution Christmas Lectures on this very topic. So I caught up with him during his rehearsals for the scientific showpiece.

1:48Lecture 1 is from your mouth hole to your bum hole, the tube, the mechanical and chemical destruction of food and its absorption. Lecture 2 is how we literally use the elements in our food to produce energy and as construction material. And Lecture 3 is about the processing. And we're building toward trying to build a deep understanding of how processing affects our physiology and how we've gone from the food system being a miracle that feeds people better than at any other time in the Earth's history

2:19to simultaneously being the leading cause of early death for humans and animals. So poor diet is now a very, very serious cause of disease. And it's also a source of real problems for the planet, carbon emissions, agrochemical inputs, loss of biodiversity, extinction and so on and so on. This is really the thrust of ultra-processed food and ultra-processed people, wasn't it? Your book, which was excellent, by the way. I really enjoyed going through it. And it's kind of of its moment, isn't it? Now's the time we need to be talking about this

2:49because it's almost like we've forgotten what food is for and where it comes from because home economics has been ditched across the curriculum in many, many countries. And as you say, the world is malnourished, not undernourished. That's a very good way of putting it. Although I disagree that now is the moment. In fact, the moment was 10 years ago or 20 years ago or 30 years ago. So in 1990, 5% of children in the UK at the age of 10 were living with obesity, which is an unacceptably high number.

3:19I mean, having an integer percentage of children living with diet-related disease is not tolerable. We've let that grow and expand so that a quarter of children now leave primary school living with obesity, roughly a quarter. So doing nothing isn't an option. And the source of the problem, and this is extremely widely agreed upon now, I don't think anyone credible could disagree, that problems like obesity have at their heart commercial incentives. They are caused by commercial interests in the same way that the pandemic of lung disease was caused by commercial interests.

3:51And so they need similar kind of policy approaches and regulation. How are you going to make this digestible for kids? Because that's really who the lecturers are targeted at, isn't it? It's young learners, people you want to inspire to become the next generation of people who will change things. The Royal Institution is the first time I have really spoken directly to a young audience in public about food. So weirdly, on Operation Ouch, which we've been making now for well over a decade, we don't do it. And we don't do it for a good reason, which is because the food on kids' plates,

4:22they don't get to choose and telling kids what safe and healthy food is, it feels very unjust when they may not be able to access or afford that food. And when other food is marketed to them as being healthy, when it probably isn't or definitely isn't. And so I think we've got two concerns. The primary one is that kids leave these lectures feeling empowered, feeling knowledgeable, not feeling anxious, and with an increased level of understanding and a reduced level of shame and stigma. There's a separate, quite discreet concern about eating disorders.

4:55And so as a result, the Royal Institution, and I do this generally, but they've taken it really to another level, they are very specifically engaged with eating disorders experts, clinicians, academics, to make sure that we are going to reduce the risk of eating disorders with the lectures, not increase them. It's very important, particularly that kids who are, you know, well on their way to becoming grownups, this is an audience of 11 to 17 year olds, that they do understand how the food system harms their bodies in the planet, and the kind of changes we need to be looking for.

5:25And that's scientific, right? I mean, the discipline of the Royal Institution is to use science as the tool, to say that good science is truly independent, good science is conducted without external influence, and the science tells us about the harms, the science tells us about the origin of the harms, and the science leads us toward the kind of policy solutions. One of the things that defines the Royal Institution Christmas Lectures, though, has got to be the demos and the interactive nature of it. So what's up your sleeve to turn food into something which can do that?

5:58I guess at the heart of the big question about food is it's an energy source. So it's full of energy and you can release that energy in all kinds of interesting ways involving strong acid, explosions, flames, and general fun RI demo dangerousness. The discipline of demonstrations makes these unlike any other lectures I've ever given, and I think all the lecturers say this, that even if you're a kids communicator, you're still pretty used to using your words. And so being forced to show things is a massive headache in a way, but once you do it, it's really, really good.

6:28And my favourite example, in lecture two, we will explain the very significant difference between the way an internal combustion engine takes hydrocarbon fuel in and produces energy, and the way your body does it. To do that, we have to turn the audience into subatomic particles. We have to inflate a reservoir with protons. We have to create a lightning bolt, and we have to create all the chemical intermediates that transmit and carry energy around the cell. The shorthand for this is called oxidative phosphorylation. And in order to explain this to kids,

6:58I've had to phone a number of professors of biochemistry. So has the RI team. We've got young experts who are working with me. I think we would all say that we have understood this process now in a level of detail that we never grasp. I definitely understand it better now than I did during my PhD. Some people have done biochem degrees, and they're like, oh, right, yeah, no, I never quite got elements of it until now. It's an Einstein quote, isn't it? You know, if you really want to... I mean, what everyone says, if you want to understand something properly, try and explain it to an 11-year-old.

7:29And if you can't, you probably don't understand it yourself. One of the things that characterise a lot of the things, people always phone in programmes I'm on, and they always want to talk about flatulence. So sorry to lower the tone, but will farts feature? That has to be part and parcel of any lectures about food. Farts feature, burps feature. We're going to do a demonstration that illustrates, I think, very, very clearly why you must not set your farts on fire. We're going to explain... I'm going to leave this as a spoiler. Are farts particles of poo? Because if farts are particles of poo, this is a huge problem, right?

8:00Because surgeons farting during operations which need sterile conditions might be causing wound infections. So we will be discussing farts in more detail than I think has ever been done before in public. I think I can say that. Chris Van Tilken there. And if you want to catch Chris, the 2024 Christmas lectures from the Royal Institution will be on BBC4 on the 29th, the 30th and the 31st of December at 9pm.

Carbon-14 Diamond-Based Battery

8:26British scientists have created the world's first carbon-14 diamond-based battery. By capturing the fast-moving electrons that are given off when radioactive carbon-14 atoms decay, none of which can actually escape from their hard diamond casing, the technology promises to provide power to devices at low levels for potentially thousands of years. Here's its creator, Tom Scott, who's at the University of Bristol. Instead of using nuclear fission, for example, which is what we do in a reactor to heat water, to create steam and drive a turbine,

8:58and in doing so generate electricity, we're actually generating electricity directly through radioactive decay. And so what we've developed effectively is a cousin to the solar panel, except instead of needing sunlight to generate the electricity from the panel, we're actually using radiation. And what we're actually doing is we're embedding inside the voltaic, the radioactive material, such that the energy is produced and converted inside a single device. And that makes it very efficient.

9:29So what materials are you using? And what's the origin of the radioactivity in the first instance? The radioactivity that we've been using in this first device is an isotope of carbon called carbon-14. And actually, carbon-14 is naturally created in the upper atmosphere. The presence of it means that we can do things like carbon dating archaeological finds. But in our case, because it's radioactive, when it decays, it releases a beta particle, which we then convert into a trickle of electricity in our devices.

10:00Now, our devices are actually made from diamond, which is a phase of carbon, which is really very hard. It's actually one of the hardest natural substances on the planet. And what we do is we grow diamonds from a gas plasma that we create. And we incorporate into the diamond the radioactive carbon. So all we're doing is we're substituting non-radioactive carbon in the diamond for radioactive carbon. Because the diamond's really dense and it's really hard, it forms a really, really good cage.

10:31So that means that we can convert the radiation energy into electricity, but also that the radioactivity doesn't escape from the device, which makes it intrinsically safe. So you've got the radioactive source, which is the atoms of carbon-14, inside the diamond. What are they hitting in order to produce the electricity and then for you to tap off the electricity, if that's all going on inside a diamond? Yeah, so we create a special structure within the diamond. It's actually what we call a diode structure. So that means that any electrons that we create within the device

11:04will flow in a single direction out of the device, which we can then connect to a working circuit. So that might be a transmitter. It might be some sensors that we can make some readings with. A beta particle actually is a, you can think of as being an extremely high energy electron. And so when that fires out into the diamond structure, you can think of it as bouncing its way through the structure. And with each sort of collision it makes with another carbon atom, energy is dissipated into the structure of diamond as essentially like a cascade or a shower of electrons.

11:37And it's that shower of electrons, which is the electricity, which is then flowing out of the device. I like to describe it as being something a bit like a sandwich. In our device, we have layers of diamond, which is not radioactive. And then we have a layer, which is radioactive. And then we have another layer, which is not radioactive again, but it's been doped in order to help with the flow of the electrons in one direction out of the device. So a bit like a ham sandwich, where the ham layer is the bit for our diamonds, which is the radioactive bit. How much energy comes out?

12:08What sort of voltages? And how long will this last? So we're talking about devices which are never going to power cars or trains. We're talking about devices which constantly trickle out a tiny amount of power, and we're talking sort of microamps at about two volts, but it would do so for a very long period of time. So the half-life of carbon-14 is about 5,300 years. And that means that with our devices, they will have hit half power output over that period of time.

12:42So in terms of human timescales, we're talking about a forever device. But in terms of geological timescales, we're talking about a device which would continue to produce power for several thousand years. What do you think you can do with it? When you know you've got something at two volts with a few microamps, what sort of things could that power? Typically, we're looking at device applications where we can use that trickle of power, either because it's a sufficient level, it can continually power a very low power consumption activity.

13:13So that could be something like you can think of as a pacemaker potentially. But for most of the device applications that we've already done sort of a prototype for, we're trickle charging a very low leakage capacitor, which is storing the electrical energy. And when that capacitor over a period of time gets full, it then will discharge itself into a working circuit, which might contain sensors or transmitters, for example. And so very much we see these devices as working in what we call a chirp mode. So every so often, a device will chirp some information

13:47or it will make a reading and then send that information. And it will do that for very long periods of time. So potentially very useful in things like environmental monitoring in very extreme places where it's either very hot or very cold, or maybe, for example, at the bottom of the sea, or even at the bottom of an oil and gas well, or where we're storing carbon dioxide. But also lots of applications in space where it can go from very hot to very cold quickly. And you also need a device which can withstand the sort of solar radiation that's much stronger

14:19out beyond these protective bounds of the atmosphere. Really, we're not looking to replace or supplant the standard lithium-ion battery. What we're trying to do is provide a power source, which is very good across extreme environments, and also in very remote locations where it would be very expensive or potentially dangerous to try and go and replace a chemical battery. Absolutely amazing. Tom Scott from the University of Bristol there. This is 5 Live Science with me, Chris Smith.

Dark Comets

14:48Still to come, dark comets. No, they're not alien spacecraft as we first thought, but instead unusual celestial bodies making strange movements. And we also put obsessive-compulsive disorder under the microscope. But first, to a new genetic analysis which has helped to pinpoint the period when modern humans first began to mix and interbreed with Neanderthals, which were a parallel species closely resembling but genetically distinct from us that lived in Europe for hundreds of thousands of years

15:19before disappearing about 40,000 years ago. Now, we know the two groups interbred once more modern humans arrived in Europe from Africa because scientists have assembled the Neanderthal genome from archaeological remains and we can still detect Neanderthal DNA sequences in our own population today. But now scientists in the US and Europe have gone a step further to identify more precisely when. They've done it by looking at how ancient and modern DNA samples have been affected by a process called recombination,

15:50which happens when eggs and sperm are made. To increase genetic diversity, the body randomly switches equivalent chunks of DNA between the two pairs of each of our chromosomes. This means that genes that sit next to each other on the chromosome tend to be passed on together like this, so you can follow them, a bit like genetic breadcrumbs. But as more time passes, they get progressively more fragmented as more recombination events slowly split them up with each new generation. Hey presto, a genetic clock.

16:20And what it shows is that Neanderthals and modern humans overlapped and interbred for potentially 5,000 years. Here's the discoverer, Arev Sumersha. One thing that was always debated was if our ancestors mixed with Neanderthals or not. And we already have an answer to that question due to the first genome of a Neanderthal that was sequenced in 2010. And the answer is yes. So all humans outside of Africa living today,

16:50they do carry some DNA from Neanderthals. And we have a broad idea when this might have happened and where, but we would like to understand better the interactions at that time between the different human groups being modern humans and Neanderthals. How can we get at the answer to that question given it was so long ago? What we use to understand it better is what we call ancient DNA. This has been a field that is growing really fast

17:21over the last 10, 15 years. And what it means is that when we are excavating an archaeological site, if we find human remains being tooth or bones, or even actually today we can do with sediments, we can extract DNA from the individuals that lived in the past using these remains. And this would allow us to jump back in time and see some of the genetic aspects of the groups that these individuals belong to.

17:52And how are you trying to then get the answer to that question, which is when and where that mixing most likely happened? What we did in my study is that because our individuals are so old that they are older than 45,000 years, we find that the Neanderthal DNA in their genomes is in the form of really long segments, which we can detect very well and very precisely. And we use those to identify how many generations have passed since mixing and when these individuals lived.

18:25And that was about 80 generations. We were able to then multiply this time with the generation time of humans, which is 29 years. And estimate when the mixing event happened. And that was about 45,000 to 49,000 years before now. Arev Sumersha from the Max Planck Institute for Evolutionary Anthropology. She just published that work in the journal Nature.

Neanderthals and Modern Humans

18:50In 2017, the first object we've been able to observe visiting our solar system from outer space first tumbled into view. Because of its peculiar cigar-like shape and the fact that it was moving in an odd, extremely rapid way, it ignited a media frenzy with speculation that it might in fact be an alien spaceship. Further investigation eventually concluded that it indeed was an alien in so much as it was from somewhere outside our own solar system, but it was nevertheless a lump of rock and somewhere between an asteroid and a comet.

19:23Space scientists called it Oumuamua, meaning a messenger from afar in Hawaiian, which was a nod to where the telescope used to discover it was located. Now, scientists have documented seven more new so-called dark comets, which are not from outside the solar system, but they do still show strange patterns of movements. It also comes in the same week that a team from MIT have described a hundred small asteroids, some just 10 metres across, in our solar system's main belt with the James Webb Space Telescope. Here, to make sense of it all for us,

19:55is David Rothery, who's Professor of Planetary Geosciences at the Open University. There are asteroid-like bodies which have been seen to move in trajectories which are not quite the orbits that they should have. The orbital path of anything around the sun is basically an ellipse if it's within the solar system, and there's some slight perturbations to orbital motion because of how sunlight is reflected and absorbs heat is re-radiated, but we have about 14 now objects which have been called dark comets,

20:25which is a bit of a misnomer, but you'll see why they're called comets. And the explanation for these non-gravitational accelerations or perturbations in the trajectory is that they must be degassing, and gases are escaping and flinging away some dust, and the reaction against the dust being thrown away is what causes the main object's speed and direction to change. And did they come from our solar system or outside the solar system? Because the original claim when Oumuamua, the first one that was documented a few years ago now,

20:56was written about, people said this was an alien spacecraft because it appeared to be coming from outside the solar system. How did they know that, and where did the rest of them come from? Yeah, well, the object now known as Oumuamua was discovered when it was screaming through the solar system at far too fast a speed to be orbiting the sun. So for Oumuamua, a few people said, ooh, it's the alien spaceship from far reaches of our galaxy adjusting its trajectory with reaction rockets or something. But no, it's just, we think, small amounts of degassing.

21:27Something from very deep space is going to have ices in it, which when you get close to the sun, the ices will flattelise, sublime, some dust will be thrown up, and the speed and direction of travel will be tweaked ever so, ever so slightly. Now, the dark comet are not interstellar objects, but orbiting the sun and about half of them are near-Earth objects. Their orbits come past the Earth and others stay out in the main asteroid belt. They're not the same class of body as a Oumuamua, but they've got the same phenomenon going on, which is material being thrown off in two small quantities

21:57for us to see, but which we can infer because of the way their orbital paths or orbital trajectories are being changed. I'm slightly disappointed that they're not alien spacecraft. That would be quite intriguing and quite a discovery, wouldn't it? But one of the things that people do speculate in some of the coverage of this is, well, these sorts of objects might be seeding life-giving molecules. So they're not themselves alien, but they might bring life that can take root on various places. Is that sort of over-egging the pudding? I think it is, Chris.

22:29To have volatiles, volatile substances, and presumably some carbon-reached material, that's the material which you need on a young planet for life to form. But these objects, they're fragments of larger things. But this class of objects we see now crossing the Earth were not there four and a half billion years ago when the Earth was forming. So it hasn't taught us really anything about delivery of organic materials to the early Earth. Talking of interesting things that are also out there and occasionally visit the Earth, as in they come

22:59and produce fireballs and stuff, those are asteroids that come and reign in on our atmosphere from time to time. There's this other paper which is documenting enormous numbers of small asteroids. And is this right, that they can see something 10 metres across, way beyond the orbit of Mars from Earth? I mean, that's just outstanding astronomy. Yeah. Well, these are observations by the James Webb Space Telescope or JWST. It has detected large numbers of what have been called decameter-sized asteroids.

23:32That's 10 metres, or a few tens of metres in size. So there's a lot of 10 metre-sized material out there, some of which will eventually get onto objects which intersect with the Earth. But it doesn't mean they're a big threat to the Earth because objects of these size probably wouldn't get through the atmosphere intact. What's the importance of the discovery then? Or is this just the James Webb team flexing their astronomical muscles to show, yeah, we can do this. This is why this is a powerful instrument. Look what sort of resolution

24:03we can achieve. I think this is a wonderful bonus discovery. I'm not sure if this was in the plan for JWST. They wanted to look for planets around other stars. They wanted to do deep sky work. And there's wonderful images we see of all kinds of things in deep space. But it just shows that when you get a new wavelength accessible to you in the infrared like JWST with high resolution, no light pollution, no thermal pollution, you're able to do a lot.

24:33And the observations to discover this class of bodies and to get the statistics on them so they can learn about the dynamics of the collision and fragmentation process going on, this is all a bonus for staring at primary targets. It just shows that when you build a good instrument you can do so many more things with it that perhaps you didn't expect. Thanks very much to David Rothery from the Open University. Well now it's time for the news and sport but stay right there because after that James Titko

25:03is going to take a look at OCD, Obsessive Compulsive. This year, experience the NHL playoffs your way. Want to watch a single? Do or die Game 7. A full week of heavy hitting back and forth series. Then check out Sling's 1-3 and 7-day passes. Watch the chase for the cup on ESPN and TNT starting as low as $4.99. No long-term contracts or overpaying. Just live hockey at home

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25:42Disorder.

OCD and Brain Function

25:43Welcome back to 5 Live Science with me, Chris Smith and right now I'm going to hand over to James Titko who's going to take a look at Obsessive Compulsive Disorder. Thanks Chris. Obsessive Compulsive Disorder, OCD, is a mental health condition where intrusive, unwanted thoughts can become all-consuming. Some people report anxieties over something terrible happening to them or someone they love for example and in some cases in a bid to alleviate these fears they may carry out

26:14compulsive actions repetitively to the point that they become extremely disruptive to their lives. Due to pervasive misconceptions around this serious psychiatric condition a lot of people suffer with their symptoms for a long time before getting help. It's also complicated to unpick the mechanisms of this disorder and we'll be exploring the ideas at the cutting edge of current research later in this programme. But first, to help us understand a bit more about OCD, I've been speaking

26:44with Patrick Dolan, a third-year student at the University of Cambridge. He first started noticing abnormal behaviours when he was 16 years old. Checking doors were locked, checking I hadn't left the hob on, continuously making sure like my dog was inside and I hadn't left him outside when I was about to leave the house. It also manifested in ways in my studies so I had to constantly reread paragraphs because I wasn't sure whether I'd completely understood it. I'd get stuck on certain pieces of work because completing it

27:15just didn't feel right and turning in assessments and just they had to be perfect for the teachers. Distortions of useful behaviours, checking your work, something that would make sense to do, making sure the hob's not on so you don't burn the house down but how would you describe it to someone who's not familiar where it turns into something more than just a rational thing? Like you say, a lot of the behaviours actually stem from normal things you would do every day. However, the obsession comes when

27:45so you go back to it multiple times so even if you see for example that the hob is turned off it doesn't feel right in your head that it is turned off and that's where like the compulsions kick in so you might need to turn it off and on, off and on off and on you might need to keep revisiting it or in some more severe cases if it's not treated you might for example leave the house and get five minutes down the road and then think oh no, did I turn the hob off? And in some cases that might require you to return back, go into the house and check the hob is off

28:16and that cycle can go on forever and ever until you actually feel satisfied in yourself. It's, I can imagine extremely exhausting when people claim to be a little bit OCD which is kind of a gross misunderstanding of the genuine psychiatric condition experienced by people like you. Exactly and I think for example if you say that you have depression when you don't you haven't actually been diagnosed people will call you out and say oh you can't just say

28:46you're depressed because you feel a bit sad like that's not fair on the people that are actually suffering from depression but if you get people saying oh I'm so OCD like I like to colour coordinate my notes I have to have everything lined up they might actually be OCD symptoms but if you haven't been diagnosed and it's kind of clear you don't have the condition then it can be upsetting for people that do and I'm not saying people do this maliciously but I think now as we have these conversations it needs to be something that we stop saying. I think you're definitely right there

29:17how have you managed to manage the condition I guess whether it be in those earlier years or more recently to limit the flare-ups? So to be honest the best thing I did was to start speaking about it I didn't know anybody else that had suffered from such a thing I kind of felt so different to everyone else I'd heard of depression and anxiety but you know I hadn't seen these symptoms in real life it's only coming to Cambridge actually when I first got there in first year that I found

29:48a lot of people were very very comfortable about speaking about the condition and that almost gave me the confidence to be like okay I'm not alone and it's from there that for the first time I could say stuff out loud I could admit it to other people to my friends and my family without feeling I was different or I was strange and it was only these conversations that actually maybe go and get help go to the NHS and get cognitive behavioural therapy Patrick Dolan describing his experience

30:19of OCD we'll hear more about the treatments available that Patrick mentioned at the end of that interview a little bit later before that though we need to try to understand what's going on inside the brain to bring on these obsessions and in some cases compulsive behaviours Trevor Robbins is the man to help us here a professor of cognitive neuroscience at the University of Cambridge The classical idea would be intrusive thoughts are often very unpleasant and cause anxiety

30:50and in order to cope with this anxiety and reduce the stress you perform this repetitive behaviour so it's a kind of coping response and there may be some truth to that but the evidence you know isn't totally clear and it's interesting from a psychological point of view that we know that avoidance behaviour for example in the lab often develops into what we call habits and habits are more automatic and they no longer really depend

31:20on the original conditions which produce them in other words you might perform the behaviour initially to reduce anxiety but then you just do it automatically and the anxiety kind of is irrelevant then in the brain there's a balance between your goal-directed behaviour and habits and we think it's kind of flipped over a bit to the habit system in OCD and so that's partly why it becomes more automatic and less amenable

31:51to cognitive manipulation as it were fascinating to hear the kind of nuance and the active debate clearly on this particular condition if we were to stick with the classical model for one minute what's the psychological sequence of thoughts that leads some people to demonstrate the behaviours the compulsions that we see because I think there's quite a few misconceptions on that topic there's a lot and you know OCD is expressed in a variety of ways but the classical example really

32:22is germs fear of infection and so this leads to excessive hygienic behaviours washing your hands so often with bleach that you actually cause damage then clearly it's a compulsive behaviours another classic example really is check-in check-in whether you've locked the door after you've left your house and maybe spending 15 or 20 minutes to ameliorate this anxiety that you're somehow your house is going to be violated in some way check-in

32:52by the way is a very fundamental symptom in OCD I mean even if you're afraid of germs essentially you're checking all the time whether your skin is clean OCD can often extend into other areas for example perfectionism and ordering which is a more cognitive aspect but again