Science Friday - Biorobots, The Math Of Life, Science Comics. Jan 17, 2020, Part 2

Episode Date: January 17, 2020

Living Robots, Designed By Computer Researchers have used artificial intelligence methods to design ‘living robots,’ made from two types of frog cells. The ‘xenobots,’ named for the Xenopus genus of frogs, can move, push objects, and potentially carry materials from one place to another—though the researchers acknowledge that much additional work would need to be done to make the xenobots into a practical tool. The research was published in the Proceedings of the National Academy of Sciences. Josh Bongard, a professor of computer science at the University of Vermont and co-author of the report, joins Ira to talk about designing cell-based structures and next steps for the technology.  The Math Behind Big Decision Making What does it mean for your health if a cancer screening is 90% accurate? Or when a lawyer says there’s a 99% chance a defendant is guilty? We encounter numbers in our everyday lives that can influence how we make big decisions, but what do these numbers really tell us?  Mathematical biologist explores these concepts and patterns in his book The Math of Life and Death: 7 Mathematical Principles That Shape Our Lives. He joins Ira to talk about the hidden math principles that are used in medicine, law, and in the media and how the numbers can be misused and correctly interpreted. The Science Comics Of Rosemary Mosco Have you ever wondered what a Great Blue Heron would write in a love letter to a potential mate? Or what the moons of Mars think of themselves? These are the scenes that nature cartoonist Rosemary Mosco dreams up in her comic Bird and Moon.   “Nature is really funny. It’s never not funny,” Mosco says in SciFri’s latest SciArts video. “You can go into the woods and find 20 or 30 hilarious potential comic prompts anywhere you go.” Viewers may come for the laughs, but they will end up learning facts, she explains. Mosco talks about her inspiration for finding the funny side of snakes, planets, and nature, and how she uses humor to communicate science.  Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

This is Science Friday. I'm Ira Flato. Later in the hour, the intersection of math and everyday life. But first, remember the 1966 movie, Fantastic Voyage? It had a really interesting plot. A submarine and its crew are shrunken down to microscopic size, so they can be inserted into a person's body into the bloodstream, travel through the arteries to repair a scientist's brain. But what if the future of that sort lies?

not in metal and silicon, but in carefully designed collections of cells, biological robots, programmed through their design to do some important function. Joining me now to talk about that, Josh Bondgard, he's professor in the Department of Computer Science, University of Vermont, and co-author of a paper this week on the proof of concept of a way to design these biorebots published in the proceedings of the National Academy of Sciences. program. Thanks very much, Ira. Thanks for having me on. You're welcome. You know, some of the stories about this have called these structures the first living robots. Is that accurate? It's close. We have a lot of colleagues that have been trying to build and successfully building machines out

of DNA and other living components. The main advance for our work here is that we asked an AI to actually design these biobots for us. So they're, so they are, they're, they're, living things? Well, I guess we could argue about that. If you zoom into one of these biobots down to the level of a cell, it is definitely a living thing. Our little biobots, we nicknamed them xenobots for the moment. They're made out of cells taken from xenopus-Lavis, the African horned frog. So they definitely qualify at some level as a living system, but they are not naturally evolved organisms. So they can't reproduce on their own then? They definitely cannot reproduce on their own.

At the moment, they're just mixtures of frog skin and frog heart muscle cells. There are no reproductive organs in there for obvious reasons. So how do they know what to do? What tasks you want them to do, and how do they do that? That's a great question. So the experiments we reported on in this study, each experiment has two phases to it. In phase one, we told the supercomputer here at the University of Vermont, what we would like the eventual xenobot to do.

And the supercomputer then gets to work trying out billions of different designs where any one design is some combination of virtual frog skin cells and virtual frog heart muscle cells. The supercomputer puts together those virtual cells in a virtual petri dish. And then the supercomputer watches this little virtual xenobot try to move along the bottom of the dish. And it scores each one. faster-moving xenobots survive and reproduce, again, all in a virtual world, and the slow-moving

xenobots are deleted and replaced by the offspring of the faster-moving xenobots. We repeat this process in the supercomputer, this evolutionary process for a few days or a few weeks, depending on what we've asked the supercomputer to do. In this case, we started very simple. We just asked the supercomputer to design us a xenobot that would move as quickly as possible. possible across the bottom of a petri dish. At the end of that day or a couple week period, the supercomputer gives us back one or a few xenobot designs. And our biology colleagues at Tufts, Douglas Blackiston and Michael Levin, then get to work and start building these xenobot designs

from actual xenopus cells. And they then take their constructs and put them in the bottom of an actual petri dish, and in many cases, lo and behold, the physical xenobot moved in exactly the way that the computer had predicted it would. Now, I'm interested that you used heart cells, is that correct, in your xenobots? That's right. These are cardiomyocytes or heart muscle cells. They're like little tiny pistons. They increase in size and decrease in size and cause the overall organism to start moving. Or not. Yeah, I was thinking. You get a beating heart cells going, and that's where your locomotion power comes from. Exactly.

And it turns out, though, in practice, this is not so easy to do because frog heart muscle cells, if they grow into the shape of an adult frog heart, they will sink up and they will all beat as one, which is good news for the adult frog. But if those heart muscle cells are rearranged into completely new patterns, like the ones dictated by the computer, there is no guarantee that the cells will all synchronize. together. So that makes a very challenging task for the computer. We want it to design a machine basically made out of cells that will move smoothly, but all the individual elements are, in a way, misbehaving. They're all firing and expanding and contracting at their own rate.

So, okay, you've got them to move around a petri dish. Big deal. True. I can do that with my pencil point, right? Exactly, exactly. What practical usage can you make of this and where do you go from here? Well, that's a good question. So as you mentioned at the moment in this first study, we just wanted to demonstrate that this technology is possible and at least how to do it for simple behaviors like movement. And it's hard to say where a technology like this will go, what kinds of applications will come out of it. We identified two potential applications for this technology.

The first one is environmental remediation tasks. So at the moment, for example, it's very difficult for us to identify, locate, and filter microplastics out of our waterways. There are attempts underway to build nets and boats and so on. But if we build machines out of traditional materials like metals and plastics, unfortunately those also degrade, and they degrade particularly quickly in salt water, like oceans where a lot of the microplastics are. So at the same time that some of those machines

are trying to clean up the oceans, they're also degrading and contributing to the problem. So one of the appealing aspects of the xenobots is they are 100% biodegradable. So it may be in working together with some of our industrial partners moving forward, we might be able to build very large swarms of these xenobots, drop them into our waterways,

and ask them to act like little small, sheepdogs can they find and collect microplastics into much larger masses that can then be scooped up by boats and nets and disposed of. You know, I'm thinking of that Michael Crichton book where these swarms get out of control once they're released.

There is definitely, as you can imagine, a lot of concern about this technology that if we are going to build very large swarms of very small things, they could get out of control. So we want to be sure to move forward very carefully with this kind of technology. It's important to remember, though, that there is no genetic engineering here. So if you zoom in to anyone xenobot, again, it's just a simple frog cell. Of course, they might act in ways we don't expect, but they are unlikely to get

out of control, unlike some other genetically engineered organisms or weaponized viruses. So in some ways they are safer than some of the alternatives. Can you mix and match frog cell parts on these to get different kinds of functionality? Well, that's actually the next step that we're already tackling. As I mentioned at the moment, they're only made out of skin and heart muscle cells. So there's no reason that we couldn't mix and match with sense organs or sensory cells as well. We might be able to incorporate, or the computer might be able to figure out how to incorporate eyes and noses and chemo sensors so that the xenobots would have a better job of sensing their local environments. And eventually we may consider including neural tissue as well so that these

xenobots can act more intelligently. Well, so at what point does it not become its own species or whatever? Well, that's a very good question. So at the moment, these xenobots are in essence frogs. They just don't look like frogs. They're very small. They're one millimeter across or they're about the size of a grain of sand. They definitely don't look like a frog. They look like a popped kernel of popcorn. But they are definitely covered by the animal welfare regulations that exist in this country, especially as it relates to scientific experimentation.

So from the regulatory body's point of view, these are simply frogs, and there are certain things we can and can't do with frogs in the lab. But if we keep pushing this technology further and further, as you mention, the eventual machines look much, look less and less like frogs and look more and more like something else. And we may need to work with our regulatory bodies to develop new regulations for these new kinds of organisms. And does each one of these have to be handmade? I mean, you're not 3D printing them, right? They sound like they have to be put together piece by piece. That's right.

So they were put together by our Tufts colleague, Douglas Blackiston, who's a very accomplished microsurgeon. So he takes, he scrapes about a thousand cells off of a very early frog embryo, disassociates the cells. So they're all free floating in the fluid in a petri dish. And then they, cells will just spontaneously glue back together. And as they do, Douglas coaxes them into exactly the right configuration dictated by the computer. So, as you can imagine, this is a very labor-intensive process to build a sand grain-sized bio-bop. So we're also looking in next steps in automating the process of manufacture as well.

Okay. We've nailed down the automating the design side, but not yet the manufacturer side. Can you crowdsource this? Can you put out a public, you know, cookbook of how to make your own one of these? That's exactly what we've done. Our PNAS paper, at least for biologists, hopefully reads like a cook. book about how we very labor intensively build these robots, and we're hoping some of our biology colleagues will weigh in on better ways to build a xenobot.

Did these computers come up with any designs that surprised you that you might not have thought of? They absolutely did, and that's the reason why we asked the computers to design them for us. It turns out that if I were to give you or even to give a biologist a thousand randomly beating frog heart muscle cells, and after you to put them together in a way that we'd end up with an organism that moves moves smoothly is a very difficult thing to do so the computers not only are good at this but they come up with lots of different designs and some of them are

wackier than others one of our favorites was the Xeno cage bot so the computer realized unintentionally that these things need to move through a fluid so there's a little bit of nutrient in the bottom of the Petri dish and if you need to move quickly through a fluid, one good way to do that is to be hydrodynamic, and one way to be hydrodynamic is to be hollow. So the computer came up with the cage bot, which is basically an empty cube where the struts of the cube are made from frog skin and heart muscle cells. And once we had that cage bot, we found out that we could also put a small pellet inside it. I'm going to have to put you on hold. I understand. I understand. Thanks, Ira.

We'll come back with the rest of the story some other time. Josh Bungard, the University of Vermont. We're going to take a break and come back, stay with us. We'll be talking about mathematics in your life. Don't go away. I'm Ira Flato. This is Science Friday from WNYC Studios. This is Science Friday.

I'm Ira Flato? You've probably seen it on one of your favorite crime TV dramas. But there's a murder case. A single drop of blood from the accused defendant is found on the same. scene of the crime. As this blood type is only found in 10% of the population, the prosecutor says there is then a 90% chance that the defendant is guilty. But do these numbers add up? That example, it's not just used on TV juries. It can be found used in real court cases. There are all sorts of numbers and stats thrown at us all the time, probabilities, accuracies, how well a drug will

work and algorithms that are used to determine the news we read to Wall Street trading, all kinds of numbers. My next guest is here to talk about mathematical misreads and misdirections and how to interpret the story behind all of the numbers. Kit Yates is a senior lecturer in mathematical science at the University of Bath in England. His new book is The Math of Life and Death, Seven mathematical principles that shape our lives. You can read an excerpt of his book on our website at Science Friday.com slash Everyday Math.

And if you have a question about any stats or math in your everyday life, that don't seem to add up or how to interpret them, give us a call. 1-844-724-8255-8-4-Sai Talk or tweet us at SciFri. Welcome to the program, Dr. Yates. Hi, I were nice to be on. Thanks for having me. You're a mathematical biologist where you study topics like egg patterning. What is a mathematics biology?

Right, yeah, it's sort of a crazy one that most people haven't heard of, I guess. And I think people find it hard to think that maths and biology can be married up together because I think at school we're taught that math is really pure and abstract and hard, whereas biology is really messy and real world, and never the twain shall meet. But actually, when I went to university, I did this amazing course in mathematical biology, and I found out that maths can be used. used to describe the world around us. It can be used to describe, you know, engineering and science and physics, but also biology as well. And so what I do in my day job is to try to take biological

systems that we're interested in. So maybe plagues of locusts or, as you mentioned, egg patterns, or for me, I am particularly interested in developmental biology, so the way the embryo forms and what can happen if something goes wrong there. And we try to represent that system using a series of equations or a computer code so that we can do some. some mathematical experiments, which may be on ethical to do in an animal, or maybe are just too difficult or too expensive to do. So we can actually go ahead and do those experiments in the computer, and we can learn something about the system.

I know your book goes way beyond biology, and in fact, it talks about how when we are presented with numbers that most people just take them at face value, it's almost as if we have never been educated enough ourselves how to judge the value of them. Right, exactly. This is one of the main messages that I want to come out of the book is that people will use numbers against us. They will manipulate us with statistics. Politicians, newspapers will throw numbers at us. And I think we're a bit too scared to question these people. What I'm not saying in the book is that you have to be a mathematician, you have to go and do a degree in math. That's absolutely not the case. But what you should feel free to do is to start to question these people who are wielding the numbers and who are manipulating us with statistics. and to say to them, well, what does this statistic actually mean? How did you calculate this? Is it the real deal? We should start to fact-check people and to call people out on their numbers.

Talk to me about what you think is the most misinterpreted fact or number that gets thrown about us at us. It's something that health statistics, for example. Yeah, I think in newspapers it's really common for them to want to ramp up the probability of getting a disease, how likely it is that, you know, a particular. lifestyle choice might impact on our lives. So I read a story a few years ago in the Sun newspaper in the UK, which said that eating a bacon sandwich every day increases the risk of colorectal cancer by 20%. I read this headline and was like, wow, could it possibly be

the case that for people that don't eat bacon sandwiches every day, they have maybe a 5% background risk, but for people that do, they have a 25% risk of getting colorectal cancer. And actually, when I dug into the story, it turns out that the real statistic is that of 100 people who don't eat a bacon sandwich every day, five of them will get colorectal cancer of the course of their lifetime. And of people that do eat a bacon sandwich, only six people will get choleractal cancer over the course of their lifetime, six people that do eat a bacon sandwich. And so that's an absolute increased risk of 1%. And that would be the honest way to present it is to say, without the treatment or without the bacon sandwich, it's 5%, and with the bacon sandwich, it's 6%.

But actually, what the sun had done and said, well, actually, 1% represents a 20% increase on 5%. And so we're going to sell this as a 20% increase in risk. And this is called the relative risk. So if you're presented in the newspaper article or a study with just a single big percentage figure, it's likely that they're giving you the relative risk. And what you really need to dig down and find is the absolute risks, which will usually be too, usually be too much smaller numbers for with and without the treatment for a disease or with and without a particular lifestyle choice. So that's one that comes up all the time.

I've seen that apply to so many medical studies, you know, about that risk between one or two, one or two occurrences for everything from statins to all kinds of other things, where people are just, they just don't know how to read it correctly. Right. And the mad thing is it's not just newspapers that are doing this. Apparently, in about a third of, um, top scientific papers that were surveyed in the study, they found people doing this thing called mismatch framing. So presenting the benefits of their drug using a big figure, the relative risk as a percentage to make it look good, and then presenting the side effects of their drug using these much smaller absolute risks and not using a percentage, using a decimal, so it looks even

smaller. So yeah, it's not just newspapers, but even in some scientific papers, this is happening as well. So, yeah, we've got to be super aware of this. So the result, the results can be accurate and yet imprecise at the same time. Yeah, exactly. Yeah, I think that's, this is something that we're also struggling to deal with when we come to things like going for screening. So there's a sort of toy problem in the book, and this was a question which was set to German doctors. And it's about going for screening for breast cancer. So these figures are for the UK, but they're similar for the US.

the probability that woman who's over 50 has undiagnosed breast cancer is about 0.4%. So that's 4 in 1,000 women will have undiagnosed breast cancer who go to these screens. And then if a woman has breast cancer, the probability that she tests positive with this test is 90%. So sounds pretty accurate. And if she doesn't have breast cancer, the probability that she's correctly told she doesn't have breast cancer is also 90%. And then the question that was asked to these doctors was, what's the probability that if you're a woman who's gone to a screen and you get sent a positive mammogram result you're told you need to go back for further tests what's the probability that you actually have

breast cancer and so they were given these five options a was 90 percent 81 percent 50 percent 3.5 percent and nought.4 percent and they were asked to answer this these are the people who are supposed to be able to interpret these results for us right these the doctors and actually most of them got the answer wrong and actually I think it's a really surprising answer and indeed when I tried the question myself, I got it wrong. If you actually dig down into the maths, you find that the probability of actually having a disease if you get a positive mammogram is only 3.5%,

which is crazy, right? It's crazy small. And this is a problem that we face with screening, that the vast majority of people who go for a screen don't have the disease. And so that means we're testing a lot of people who don't have the disease. So when there's a test which has, maybe even, it sounds quite high, a 90% accuracy rate,

But if 10% of the people who don't have the disease, which is, again, the vast majority of the people are told that they do have the disease, that's a huge number of false positives in comparison to a relatively small number of true positives. It sort of explains why these false positives can dramatically outweigh the true positives. What I need to be careful here to say, firstly, I'm not bashing doctors. I think they do an incredibly difficult job and to expect them to be on top of all the numbers is difficult. And secondly, that I'm not advocating not going for screening. Don't stop going for screening. But what I am saying is take the results of screening with a pinch of salt and be aware if you get a positive result that it's not necessarily the end of the world. Like I tell a couple of stories in the book about people who've made dramatic choices because they've got these letters telling them that they have to go back for further testing.

And they've, you know, they've fretted and worried and really stressed about this. And when they go back for the test, it turns out that it was a false positive as it was always likely to be. So taking these results with a pinch of salt, you can get tests which seem accurate but are actually quite imprecise. Our number 844-724-8255. Lots of interest. Let's go to Naples, Florida. Sunny Naples. Ted, hi, welcome to Science Friday. Hi, how are you? Hi there. Go ahead. I love NPR and I love Science Friday. Your name is Neil. Is that right? No, it's Ira. Neil hasn't been around for years. I know. I'm embarrassed. Do you have a question now that you can unembarrass yourself?

Yeah. Well, I have a comment. In 1982, I was identified by a urinalysis test in the Army overseas. And 10 years later, I was ordered reinstated by a federal judge because, and they had a big blue-ribbon panel surgeon general's review, what they're going to do with these thousands of false positive cases. and I was one of them, and 10 years later I was ordered reinstated. Lawyers would not help me because there's no money

and there's no damages you can get from a military enlisted person's drug case. How do you react to that, Kit? Right, yeah. I mean, obviously I can't comment on the case itself. I don't know the details, but yeah, interestingly with these tests, the reason why, you know, for example, athletes get drug tested. When they get drug tested, they have their samples split into an A and a B sample, so that if something goes wrong with the first one, they can test the second one. And it's a really interesting fact that if you just run a second version of the same test on the same person,

assuming the results are independent of each other, you run a second version of the same test. You can dramatically improve the precision of that test. You can dramatically weed out the number of false positives that you get so that you don't get this same sort of problem of labelling people incorrectly. So, yeah, another message from the book is to ask for a second opinion. Both ask your doctor to tell you where the figures come from and to explain them to you, but also running a second test can dramatically reduce the rate of false positives. And that's why athletes do have these A and B samples so that they can be exonerated

if something goes wrong with the first test. So, yeah, that's a good strategy. Let's go to Roger in Missouri. Hi, Roger. Hello. Hi there. Go ahead. One quick question, and then a real question.

Can you predict mathematically the odds that a politician is lying? That's number one. But the real question is, the idea of this DNA test where they tell your ethnicity, like, oh, you're 14% Finnish. You're 3% Cherokee. Isn't that dependent upon the sample size of the global, you know, sample? Are they messing with our numbers by just simply declaring your, ethnicity through some percentage.

Okay. Right, yeah. So, I mean, the basic assumption in terms of politicians is to assume that, yeah, 100% of things they say are lies, right? But seriously, no, there's no, there's no accurate way to sort of determine that, but we do have really good fact checkers now. And that's something that we need to be doing more of is, is actually after there's been a, we just had a general election here in the UK, and after the debates between the leaders, various websites were fact-checking what they'd said. And we need to not just watch the debate, but we need to watch the follow-up and see

what percentage of the things they were saying are true or false and really read up on those fact-checks. Before you answer the second question, let me just remind everybody who we are. This is Science Friday from WNYC Studios. And I can get a little plug-in for your book at the same time. Shoot, go for it, me. Talking with Kit Yates, author of The Math of Life and Death,

seven mathematical principles that shape our lives. And I love this kind of stuff because we deal with it every day on Science Friday, how to understand the math of the stuff that we're reading. And the second part of our listener's question was about these genetic testing services. And in your book, you didn't have a very good experience with them, did you? Right. So, yeah, I actually decided that it would be a fun thing to do to send off one of these spit kits. I went to 23 and me and got my, my,

DNA profiled and it and it came back and it said that I had a genetic mutation in a particular gene, the apoe gene, which stands for apolypoprotein E if you want to know that, which basically said that I have an increased chance of getting Alzheimer's. And this worried me quite a lot. And so I decided that I wanted to figure out exactly what these figures meant. So I went and looked at the maths that they use. And actually it turns out that there's been a study done that looks at the accuracy of the way that these companies are calculating our disease risks. And it turns out that different companies, based on exactly the same genetic profile, will classify you into different risk categories because they're using slightly different mathematical formulas to calculate the risk. So my

experience was that actually I'm not going to get too worried about this genetic mutation I have because actually I'm not sure that I trust necessarily the maths. In terms of the background, yeah, and you know your genetic makeup, where you come from in the world, I also wouldn't read too much into those. I think the bigger their databases get, the more accurate they can be. But at the same time, I wouldn't take them 100%. I wouldn't believe them 100%. You don't think that people are intentionally misdirecting our numbers intentionally to fool us or or maybe they don't understand the mathematics themselves, which would be worse, wouldn't it? Right. I think, I think it's a bit of both, actually. I think sometimes it's conspiracy and sometimes it's mess up, but it depends

who you're talking about. I think lots of people are genuinely trying to do their best and just get the maths wrong, but I think there are definitely people out there who are manipulating numbers, newspapers, for example, the example I've already given, I guess, newspapers want to sell copies of their paper. They want to drive traffic to their website. And so the more sensational they can make a statistic, the better. Similarly, politicians have got a vested interest in furthering an agenda. And so if they can tweak the numbers to make their agenda look better,

then they'll absolutely do that. And be aware that there isn't going to be much comeuppance for them. There really are very few slaps on the wrist for politicians who deliberately, misleaders with numbers. You think the pollsters are accurate these days? Yes and no. I think people like Nate Silver are doing a really good job on 538 where they're taking a whole group of polls

and they're giving them different weights and averaging over them. But polling's really, really difficult to do. Predicting the future is a really hard thing. There's a nice example in the book of the literary digest when they were predicting an election over in the United States. It was Roosevelt versus Alf London back in 1936, I think it was. And they went out and they polled 10 million people. They polled a quarter of the electorate in the United States at the time.

And they predicted a massive landslide for London. And it turned out that Roosevelt won by the biggest majority for hundreds of years since 1820, I think. And the reason they got it wrong was because they had a biased sample. They'd chosen the people to sample. from a list of people who had telephones and for people who could read and write really well. And what they found was that they got people who were typically more affluent

and therefore more right-leaning and had gone for the Republican candidate London and hadn't gone for Roosevelt. So they got the result dramatically wrong despite having this huge sample. So predicting the future is super, super hard. My future here is a station break. So we have to do that.

Well, stay with us. We're going to come back more and talk with Kit Yates, author of Life and Death, seven mathematical principles that shape our lives. We'll be right back after this break. This is Science Friday. I'm Irafledo talking with Kit Yates, author of the book, The Math of Life and Death, Seven Mathematical Principles

That Shape Our Lives. And we've been talking about ways that math has been used for good and for bad and make, where people make mistakes with math. And I think what concerns a lot of people when mistakes have, with math, they're really worried when it happens in the court system kit. Tell us about this interesting case called, named Sally Yates in your book. Yeah, Sally Clark. Yeah, she was a mother. Oh, it's not. Yeah, it's me. Don't worry. That's fine. Yeah, Sally Clark. She's no relation of mine. But yeah, so Sally Clark's case is often called one of the worst miscarriages of justice

in UK legal history. She was a mother of two children. She, unfortunately, the first child she had died within about six weeks of being born. And then she tried for a second child with her husband and that child also died. And because those two children had died so early on, the police got a bit suspicious and they arrested both Sally and Steve Clark, her husband. But because Steve wasn't there for the second death, he was let go. But Sally was prosecuted for these murders. And when she came to trial, there was an expert witness called by the prosecution, a guy called Sir Roy Meadow. He came up with a statistic, which was something that the jurors took away with him,

as probably the most important piece of evidence. And he basically said that if Sally Clark was innocent, the probability that her two children died of sudden infant death syndrome, which is cot death, so a possible alternative explanation, was as low as one in six. 73 million and basically left the rest of the jury to assume that the probability of her them being guilty was therefore extremely high. And what happened, though, was that he'd actually made a few mathematical mistakes. One of them was called an independence mistake. So he'd taken the figure for the probability of having one child die of sudden infant death syndrome, the sort of the innocent explanation for her children's deaths. And that was one in 8,000.

and for a family like the clocks who are sort of middle class and affluent. And then he said, well, if that's the figure for one child dying, then the figure for two children dying, I must just multiply that together by itself or square it. And he came up with this figure of one in 73 million. But of course, that makes the assumption that two children dying of sudden infant death syndrome are independent of each other. And actually, they're not because there are a variety of factors,

which means once you've had one child die of sudden infant death syndrome, it's dramatically more likely to have a second child die from the same condition. Things like if you smoke, if you share a bed with your children, there are genetic factors that are linked to sudden infant death syndrome. So he'd made this mistake of assuming that they're independent and he'd come with a probability of this innocent explanation of being far lower than it should be. So that was one of the most significant mistakes that he made.

But one of the other ones is actually so common in courtrooms that it has its own name. It's called the prosecutor's fallacy. The idea is that it starts by showing that if the suspect is innocent, seeing a particular piece of evidence is extremely unlikely. So if Sally was innocent of killing her two children, then dying of sudden and death syndrome was extremely unlikely. That was Meadow's premise.

And actually, the prosecutor then deduces incorrectly that the alternative explanation, which is the guilt of the suspect, is therefore extremely likely indeed. But what the argument neglects to take into account is that any possible alternative explanations in which the suspect is innocent. So maybe Sally Clark's children dying of natural causes, for example, and not taken into account. And it also neglects the possibility that the prosecution is proposing, which is murder, is actually just as unlikely, if not more so. The frequency of double murders is far lower than the frequency of double sudden infant death syndrome. So when you weigh those up, it paints a very different picture.

of the probability of Sally Clark's guilt, but the jury would just lead to believe that the probability of her being innocent was as low as one in 73 million, which wasn't the case. And that's the problem with having what you call a binary answer to things, either white or black is or no guilt or not guilty. Right. I think so. I think, yeah, binary is obviously the system that we're using our computers, and it's great for computers because they work on binary logic, you can run a little current through a transistor and it can give you a yes or no answer. But actually, when it comes to human affairs, binary answers are not that useful. Humans aren't black or white.

Although some of our favorite characters, we like to have goodies and baddies, but actually some of our favorite literary characters are actually morally ambiguous that people like Severus, Snape or Hamlet, people who are both good and bad. And everyone has a little bit of that in them. So, yeah, trying to characterize people as good or bad or one thing or the other is not particularly helpful. So binary isn't a particularly good number system for us to use in terms of human affairs. There are all kinds of great number of systems in Kit Yates' book. Didn't even get into the base 12 that you talk about.

All kinds of really interesting. Great stuff in this book, the math of life and death, seven mathematical principles that shape our lives. We have an excerpt on our website at ScienceFriety.com slash everyday math. Kit, thank you for taking time to be with us today. Great book. It's been absolutely pleasure. Thanks for having me. You're welcome. Have you ever been out walking around a lake when you suddenly spot a great blue heron perched on a log? And you think to yourself, I wonder what kind of love letter she would write to her mate.

No? What's wrong with you? Maybe you've pondered about the internal monologue of a snake right before it eats a mouse. They'll know. Well, for those of us who are not so lovely, to view nature from this lens. We have Rosemary Mosco to imagine these scenes for us. She's a nature cartoonist and science writer and creator of the Bird and Moon comics. Her cartoons are featured in our video pick this week. You can watch the video of her animated comics on our website at ScienceFriiday.com slash comics.

Luke Roskin put her comic book into motion. Welcome to Science Friday. Thank you. It's great to be here. Now your comics, as I was trying to make the point, maybe not so well, they take a humorous take on nature. What is your inspiration for that? Is it their behavior, how we relate to nature? What about the nature? But about nature is so funny to you? You know, I think that everything about nature is really funny. I feel like as scientists or science-minded people, we're sort of encouraged to be very serious.

but there's just so much funny stuff. I mean, I have a cartoon about a beetle that pretends to be an ant's butt and clamps onto the ant and rides around and gets a free ride. Like, how could you not think that's hilarious? I just think that's amazing. We actually have a clip of that that we're going to play now.

Great. Hi, I'm a beetle. Is it okay if I climb onto your waist and ride around on you? What? Why? Well, I'd get a free ride plus the food and protection of your aunt colony. Hmm. What's in it for me? Um, you'll look like you have two butts.

I'm in! Ow! Amazing! So many butts! That was our video producer, Extraordinaire Luke Roskin, taking your cartoon and turning it into an animated video with voices that people might recognize on our staff. That was wonderful, Rosemary. Thank you. Yeah, that, um, that, um, that, um, that, voiceover experience. You know, I sometimes do little voices when I'm doing my comics, but having

your team do the voices was just about the coolest thing I've ever experienced. So neat. It's our video pick of the week by Luke Ruskin. How do you come up with the idea? Did you come up with that one, for example, for ant butts and on all the other ideas you come up with? Oh, so the antibuts came from an entomology club lecture that I went to where I met Dr. Daniel Kronauer, whose team discovered. the ant-butt beetle, and it's actually named after him, which I think is the absolute greatest honor that could be bestowed upon any scientist. I feel like humor is really hard to just sort of, you know, concentrate and have happened. So I just try to go to as many

lectures as I can, pretty much. Yeah, well, I have to say one of my favorites of your cartoons is the one where a snake and other predators are discussing venomous versus poisonous. And And while they're discussing it, the lunch gets away. The snake had come across an animal to have for lunch, and while they were discussing it, he runs away. So it was kind of funny. Did you actually see that happen in your head some point when you were watching a snake and a prey? You know, I owned a pet snake for a little while, and a lot of people are really afraid of snakes because I think they're sort of, you know, clever and these vicious predators.

but snakes are, they're mostly just looking for something to eat and something, you know, warm to sit on. And that's kind of the extent, you know. So there are a lot more chill than we think. But for that one, I was more thinking about how we all sort of really focus on terminology. And sometimes if we spend too much time focusing on it, we lose sight of the big picture, which would be, you know, snapping up our lunch before it runs away. Yeah, that's true. Yeah.

You're a fellow science writer. I'd like to know how you decided to go to the root of comics because, you know, I think things are funny. I haven't gotten that direction yet. The more I try on the radio, it doesn't help. Well, you should. Comics are something that, you know, anyone can do. You know, you don't have to be able to draw. You can use photos.

But I always, you know, I grew up reading the funny pages, which I know is dating myself. but I really liked, you know, Bloom County and Calvin and Hobbs and stuff. So it was just kind of natural to make cartoons about the things I was looking at. And then I also happened to be this big nature nerd. So that's what I made cartoons about. When Luke Graskin animated them for you and for us, did you see something in them that maybe you hadn't seen before? Did you get a different view on your work?

Was there value added there? Yeah. No, there really was. It was cool to have all the different characters, have their own. unique voices. You know, making cartoons is a really solitary, quiet experience. So it was really neat to have him come and visit me, you know, and be able to kind of have someone talk me through my work. And then, yeah, it's, now I want to write like animal plays or something. It's so cool to have people voice that stuff. Well, we'll team up. You also draw comics about space.

Is your inspiration for space different, of course, than your animal comics? You know, I did one cartoon about Mars's moons, and then I did a graphic novel about the solar system. And that was more, that was a job that I got. And I'm really not as knowledgeable about space as I am about animals and plants and stuff. But one cool thing about being a science writer and communicator, as I'm sure you know, is that you can get excited about anything once you start reading about it and then just dive into it. Yeah, you can teach yourself this stuff that you don't know

or have the smartest people in the world teach it to you. Yeah, that part is key. That is great. Usually, I'm the dumbest person in the room, and I'll prove it every week. You're listening to Science Friday from WNYC Studios. Ira Plato talking with Rosemary Moscow, who is a nature cartoonist and science writer, creator, Bird and Moon,

and Bird and Moon comics. How long have you been writing those? The website, Bird and Moon, I started in 2004 with a long-form comic about a lonely bird who meets the moon, which is why it's called Bird and Moon. People always assume there's someone named Bird and someone named Moon, and there's two of us, which would be great.

I would love to have an assistant, but I don't have one. But I was making comics long before that. I had a cartoon in my high school newspaper, you know, the criticized school policy, which I feel like a lot of cartoonists have. So, yeah, long time. You must have a philosophy about what you're doing. Ah, yeah. There's a lot of pieces to it.

I think maybe the most important thing for me is that if you add a joke to pretty much any fact about the world, people will share it regardless of sort of the content of the fact. So adding humor really helps spread science, I think, and I think that's really important. That's kind of my goal. Do you have any cartooning role model, any famous cartoonists or humorous? Oh, my goodness. So many.

Man, I mean, this could take hours. Just get me the top 25 or 30. How long do you have? Okay, well, I think a major... influence for me is some of the other science web cartoonists. So there's Zach Wiener-Smith who does Saturday morning breakfast cereal. There's Beatrice the biologist, which is more a microbiology. There's black mud puppy.

There's so many. There's not, you know, we're a small club, but we all know each other. And yeah, we all kind of support each other. So that's really nice. How about the classics, like the classic Harris cartoon? Classic Harris cartoons. Oh, I don't know those. Oh, I have to send you a book of these science cartoons. Yeah. Oh, my goodness. Yeah, I mean, I grew up with like the far side and this incredible book called Clan Apis and, you know, a bunch of that stuff. But yeah, I could always use more. So mentioning things that you read, what do you watch or read that inspires you to go in some direction? Oh, well, like I said, coming up with jokes is challenging, at least for me. So I pretty much just try to get as much info in front of my face as I can.

I have a whole bookshelf that's all field guides, and I'm an absolute field guide addict. Like, anytime there's a new one, no matter how obscure, I buy it. So I have one about bark. I have one about the bumblebees of the, you know, eastern United States. I have all these really obscure guides. The ants of New England is one of my favorite ones. And I just kind of go through those until something pops out that's funny, which with animals, especially bugs is not very long.

Well, in the video, in Luke Roskin's video, it shows us you out in the wilderness. Is this in your own backyard, or do you go to parks and places? Oh, gosh, yeah. I go hiking as much as I can all over the place. I'm also really interested in urban nature, so I go out and, you know,

hike around the city and stuff. But, yeah, I get out on long hikes as much as I can. And then I see things that are really funny. That's great. That's great. I'm envious of your job, Rosemary. And thank you for taking time to be with us today. Rosemary Moscow is a nature cartoonist and science writer and creator of the Bird and Moon Comics.

You can watch the video for animated comics on our website at science friday.com slash comics. Thank you, Rosemary. Thank you so much, Ira. Maybe we've started a wonderful relationship in video comic books. Yes, please. Join us. Okay, we'll be there. And on the Science Friday Voxpop app, we want to talk to.

you about our next degree of change. We're looking at how climate change is affecting Native American communities. And of course, we're always looking for your comments, especially on the Vox Pop app. If you're a tribal member, we want to hear what adaptations you and your community are making. Maybe if you're in Alaska, you have to move back from the oceans because the permafrost is melting. If you're someplace else near a river or anything, I'm just making this stuff up. I don't know what you're going through. That's why we want you to tell us what it is. Download our Science Friday Vox Pop app and tell us if you're part of a Native American community, if you're a tribal member, we want to hear what adaptations you and your community are making. That's on Science Friday

Box Pop App, wherever you get your apps. A lot of great stuff today. I hope you can listen to it again on our website or, you know, you can listen to it as a podcast all weekend long. Have a great weekend. in New York. Hi, folks. Ira here with a message of thanks from all of us here at SciFry. Thank you for making 2019 a great year by listening and downloading our podcasts, reading our articles, watching our videos, sharing with us, and importantly by donating to support our programming. I've said this before and I mean it. We can't do this without you. So thanks and cheers to more science in 2020.