Podcast 1 - transcript
Podcast theme: A second look
In our first episode of '#MadeAtUCL Disruptive Discoveries', our host Suzie goes beyond the surface to discover stories about:
- the face of Britain’s oldest near-complete skeleton - with Professor Mark Thomas, Professor of Evolutionary Genetics in the Division of Biosciences
- the characters of the London Underground - with Professor Dryden Goodwin, Professor of Fine Art in the Slade School of Fine Art
- the potential pitfalls of forensic evidence - with Professor Ruth Morgan, Professor of Crime and Forensic Sciences in the Faculty of Engineering Sciences.
Suzie McCarthy: This is Made at UCL: the podcast. Bringing you closer to the UCL research answering life's big questions from engineering to art, healthcare to space exploration, ancient artifacts to the technology of the future. Hello. I'm Suzie and I graduated from UCLA this year with a degree in Arts and Sciences. Most people choose to focus on one subject at university. But I couldn't pick just one thing. I've always been interested in just about any subject I could get my hands on, even maths. I wanted to read every book in the library to find answers to questions I didn't know existed. I tried my best, but there's a lot of books. Now, UCL has asked me back to make this podcast for you, which suits me just fine because now I get to tiptoe into every corner of the university and leave no page unturned. And I'm taking you with me!
I initially chose the stories for the first episode because they all seem to be about appearances, but as I talked with the academics behind them, I realised that a first glance is too fleeting. Often knowledge only reveals itself when we question what we think we already know and take a second look.
First, we're hearing from Professor Mark Thomas. Mark is an evolutionary geneticist here at UCL. And last year, he and his colleagues got their hands on Britain's oldest complete skeleton. They wanted to sequence his DNA to find out what he could tell us about our evolution. Cheddar man, found in Cheddar Gorge in Somerset (also home to my favorite cheese), lived in Britain 10,000 years ago. But as interesting as excavated bones might be what the researchers were really excited about is what Cheddar man can tell us about... Farming.
Mark Thomas: From an archaeological point of view, farming is an extremely interesting, well studied area.
Now, the fundamental reason for that is because it is such a major change in the way humans live. One of, if not the biggest, changes since humans first walked the earth. So, prior to farming, virtually nobody in the world could digest the sugar in milk as an adult. Now, about a third of people in the world, as adults, can happily, merrily digest the sugar in milk. And that's a trait that's evolved since farming arose.
We had a welcome funded project broadly interested in human evolutionary history in the British Isles over the last 10 or 20,000 years. So, the broad idea was to get DNA from the bones of British people over a time span of around 10,000 years, and then to look for which bits of our genomes have changed the most rapidly. And we were interested in various things. So we were interested in, firstly the process by which farming came to Britain. There's been a long debate for over 100 years about whether it was brought to Britain by people (so as a migrating people), or whether it was just the spread of ideas to the indigenous people that lived in Britain.
So Cheddar man was one of our samples. He happens to be the oldest near complete skeleton found in Britain. He lived around 10,000 years ago. So that was before farming came to Britain. That was about 4,000 years before it arrived. So at that time, Britain was occupied by hunter gatherers. So if we have DNA from cheddar man and his ilk, and from other hunter gatherers prior to farming, and then we get DNA from early farmers as they come into Britain, we can then ask the question: is there genetic continuity? Are the early farmers actually descended from those hunter gatherers, or are they descended from farmers we know were spreading across Europe over the last nine to 6000 years?
So when we want to get DNA out of a dead person, turns out that the best place to extract it from is a bone called the petrous bone, which is a small bone just inside the inner ear. We drill into skull and just get scrapings; a small amount of drill shavings, of dust as it were from the petrous bone. And then we put it into various chemicals that dissolve away the bone, but don't damage DNA. So they leave DNA behind. And then we can put that DNA into very, very advanced machines that enable us to read [a] very large amount of that DNA that we've extracted from that bone.
The first important thing about Cheddar man is that he yielded quite a lot of DNA and quite a lot of DNA information. So for example, we looked at the gene that effects whether he can digest the sugar in milk as an adult. Unsurprisingly, he couldn't, because we know that he's a hunter gatherer. He's a pre-farming hunter gatherer and we know that that trait evolved after the arrival of farming. One set of genes that we did look at was genes that affect pigmentation, particularly eye pigmentation, and skin pigmentation. Now I should make it clear that we don't know all the genes that affect skin pigmentation and different variants of genes affect pigmentation in different populations. But we do know some of the real major ones, some of the ones that have a really big effect, and we were able to look at those in Cheddar man and he came out as having light, probably blue eyes, but very dark to black skin pigmentation. Now, that was a surprise to a lot of people. I must confess that we had our suspicions that would be the case. And the reason we had our suspicions was because hunter gatherers from Europe showed somewhat similar patterns. Now, at the time a television company had become interested in the work we were doing, and wanted to make a program about it. And they were a lot more surprised. And I suppose what they're really doing is they're reflecting the fact that the public would be surprised that one of the most iconic ancient humans from Britain was effectively black skinned. They made this TV program they did a press release, and it was accompanied by this beautiful reconstruction of Cheddar man made by the Kennis brothers.
So that just hit the news. I mean, it was on the front page of virtually every newspaper. So, okay, fine, for some reason people found that really interesting or surprising but then I went on some of the online pages where of course the public then get to comment. One of the funniest ones was the Mail Online. Where there's a whole lot of, you know, things like:
"This is political correctness gone mad." Haven't heard that before.
"Next, they'll be saying that Jesus had a dark skin because he was from the Middle East." Where did that come? I mean, he probably did! What's the big deal there?
"There is no way we could know what he would look like, you'd need a time machine, this is rubbish." So I was like: well, no, you just need some DNA from them...
I actually bothered to respond to one of them where it said something along the lines of: "these scientists are just trying to destroy our identity." [sighs] You know, that just bewildered me. I couldn't help myself. So I think I responded by saying something along the lines of: "If your identity is based on the skin pigmentation of some West Country bloke from 10,000 years ago, then maybe you need to rethink it.”
I mean, skin pigmentation is primarily determined by two forms of melanin, and they absorb the damaging wavelengths of ultraviolet. So it's a protector. When populations live at higher latitudes, there's less ultraviolet, and for one reason or another, they've evolved lighter skin pigmentation. Probably the main reason for that is because when you're at higher latitudes… Most people in the world get most of their vitamin D, not from food, but from the action of sunlight. When you're at high latitudes like Britain today, it's very difficult for most of the year to make any vitamin D from sunlight. It's just the sunlight's simply not strong enough. And so, one way to make more vitamin D is to have lower skin pigmentation. Cheddar man didn't need that because he would have had a diet that was rich in vitamin D. When farming started people at less meat, less fish, more grain. That's low in vitamin D. They would have needed to make more vitamin D through the action of sunlight. So having lighter pigmentation would help that.
I think we all are susceptible to something called confirmation bias, which is that we take a view for one reason or another. And then we simply go on some Odyssey, cherry picking what we can learn and only learn things that support our views and reject things that argue against our views. Having said that, I think is extremely important, of course, to get information out that in some way equips people to argue against these quasi-racist views. You know, information about how we're all related. And, you know, so fundamentally the web of human relatedness is extremely tightly spun. And, you know, getting across these ideas, I think can help.
This is merely a byproduct of our bigger research question. As all scientists do, we wrote this up as a scientific publication. And the primary focus was, of course, on: was farming brought to Britain by migrating farmers, or was it spread as an idea to the indigenous population? And we, we showed very conclusively that it was brought to Britain by migrating farmers. The pigmentation thing, the eye and skin pigmentation thing, it's just a footnote, really. I mean, we mentioned it but, you know, from a scientific point of view, it's just not that surprising. But from a media point of view, it was, you know, it seemed to get some attention.
Suzie McCarthy: Mark's reaction to the response to his research made me think about how media and science interact. Often, the stories we see reported focus on attention grabbing headlines and miss out key research findings. Throughout this series will be rectifying that by focusing on what it is that researchers themselves feel is important about their work. Later in the episode, we'll be unearthing more skeletons as we take a second look into the reliability of frantic research.
But first I want to take you underground, specifically to the London Underground. Through ticket gates, down escalators and between closing doors, there is a whole life that you may not have noticed before. In 2010, Dryden Goodwin, professor at UCL's Slade School for Fine Art, was invited to document some of that life by Transport for London's Art on the Underground. Dryden spent up to an hour with 60 individual Jubilee line workers, drawing them as they manned lively stations and drove trains down dark tunnels. He made a short film for each of the 60 drawings as they took form and recorded the conversations that took place as he put pencil to paper. We've put together some of these recordings for you now, joining Dryden and Tracy by the tickets gates at Canary Wharf.
[sounds of trains and from the ticket gate]
Tracy: My neighbour upstairs, funnily enough she she always calls me Audrey Hepburn, cos of my long neck. And my daughter's got exactly the same but she's extremely beautiful. She's absolutely stunning. Because my cheeks are so big, especially when I smile, I'm like poor man's version of Julia Roberts! [laughs] So my face to me feels out of proportion. Not a lot of white people have such big lips. Possibly Angelina Jolie. But she's getting paid a **** load more money than I am for these lips!
[ticket gates beeping, sound of escalators]
Claude: That doesn't look like me.
Dryden Goodwin: Give it time give it time. [station noise, people talking]
Claude: So they're gonna think I'm dark skinned. Which I don't have a problem with.
Dryden Goodwin: [laughs] It's light man, it's light and dark.
Claude: Would you put as much pencil on [for a white person]?
Dryden Goodwin: Yeah, if they were in sh...
Claude: If they had shade, in shade.
Dryden Goodwin: If they had light on them, it's all about the light. I'm trying to do the light.
Claude: Yeah, yeah it's the light.
So I, I make music. So I'm like a music artist. R&B, soul, I'm big into pop at the moment. Just natural. Just, I hear beats and... [ticket gate beeps] I just, like when I hear the beat I think of what goes over it. I've got my dictaphone close. So right here it'd be like: boom, chik, boom, boom, boom. Then we go to the studio and try and create it.
Dryden Goodwin: That's great.
Claude: So this job is really good for creating music. Cos, getting inspiration as well.
This train is now ready to depart, calling all stations to Willesden Green, mind the doors please mind the closing doors.
[train starts moving]
Peter: We've had brand new trains on the Central line, brand new trains on the Jubilee line, brand new trains on the Northern line, brand new trains being introduced on the Victoria line... Brand new trains for the Met and refurbishment on the Hammersmith and City and District. It, just to be part of that is just you know, we're only on earth for about what 80 years on the whole. In 100 years time they'll be saying: "the Jubillee line extension was opened up and extended to Stratford" and, and, you know, that's very exciting to be part of the history and historical factor of that.
[sound of train slowing down]
Ashanti: I'm retired, I'm retired, I'm only doing part time now. All the changes, the development... It's quite different, a different world I see. [pause] Everything is better to me. [pause] This part time does help me, [instead of] sorta staying at home and looking at the four walls, it keeps me going and I'm glad for that.
Tracy: [ticket gate sounds] Within the first year of me working here, a gentleman come down the escalator, had a massive heart attack. 40 minutes before an ambulance service got here, 30 minutes we was trying to do CPR, save this guy's life. It hit me pretty hard. Not because, I mean he wasn't really an old guy and he was quite healthy and everything. It was just the fact that it was coming up to Christmas and he died. So I'm sitting there thinking "God, I can't let this man..." So I held his hand. It was, it was really awful. But I held his hand because, and I said to the police when they was like taking their information away: "please just let his family know he didn't die by himself. That someone held his hand and talked to him and said his name. Because I do not want them to think that their father, or their husband, their brother died on an empty platform with people all around him and no one caring.
Dryden Goodwin: We're close.
Peter: Yeah, I can see. I've just got part of my chin missing.
Dryden Goodwin: Part of your chin?!
Peter: It could be a shadow.
Dryden Goodwin: It could be a shadow.
[train slowing down]
Claude: I don't think I've ever had a man look at me so deeply as you do. [Dryden laughs] I don't know what to say: ask for your number or go away! I don't know what to do!
[train slowing down]
Dryden Goodwin: [speaking to Sue as she drives train] The look of concentration, I'll show you this when we stop.
Sue: Yeah, unfortunately when I'm concentrating I am very...
Dryden Goodwin: Yeah, no, no it's great. [train stops] Look, can you see it in the? [brake goes on]
Sue: Yeah, oh god! I look like Boadicea!
Dryden Goodwin: You look fantastic! How do I get out of this?
Sue: You can go out through the tradesman's. [doors open and close].
Dryden Goodwin: Boadicea!
Sue: Right, where that lot is standing... [platform announcement]
Dryden Goodwin: I'll jump off here.
Suzie McCarthy: That was Tracy, Claude, Peter, Ashanti and Sue. Sharing moments of their lives with Dryden as he sketched their portraits for his project Linear. Reflecting on his work, Dryden says:
"Drawing someone you've never met before results in an intense encounter, and enables a unique intimacy to develop. As the portraits unfold, so too does the openness in the conversation. Linear is all about different types of connection.”
If you'd like to see the drawings, a selection are featured on our website, where you'll also find all the links you need to watch the videos and hear more TfL stories.
Our third and final feature takes us from finance to forensics. If you've seen shows like CSI, you might think that forensic evidence is the ultimate form of evidence, with the power to crack criminal cases once and for all. Forensic seems like an exact objective science, that provides the truth as to who done it. But what if the people responsible for gathering and analyzing that evidence and making decisions that end up sending investigations down the wrong track? I went to speak with Professor Ruth Morgan who founded the UCL Centre for Forensic Science. And she's taking us back.
Suzie McCarthy (in room with Ruth): ...Back to Skeletons.
Ruth Morgan: Back to skeletons. Cool. So yeah, so one of the things...
Suzie McCarthy: Before we hit record, Ruth joked with me about how job involves not just writing papers and reading literature, but also firing guns and burying fake skeletons. One of the strands Ruth's team are investigating is how human decision-making in forensics impacts on criminal cases. She told me about an experiment in which she and colleague Dr. Sherry Nakhaeizadeh, tested whether or not participants correctly identified a skeleton as male or female.
Ruth Morgan: We set up a series of experiments where we had a male skeleton that was buried in a grave along with a number of artifacts that you'd often find in graves like coins and phones, and clothing. And we got our participants to excavate the grave, recover the skeletal remains, bring them back to the laboratory, lay them out, and then assess whether the skeleton was male or female. And we did this with a very clearly male skeleton,
Suzie McCarthy: And how do you tell the difference between genders* of a skeleton?
* Suzie had meant to say sex of a skeleton here, as skeletons don’t have a gender! This is because sex is generally seen as a biological characteristic and gender is seen as a socially determined characteristic.
Ruth Morgan: [laughs] There, there are a number of ways. Generally speaking, the pelvic area is the place where there's the most discrimination between male and female.
Suzie McCarthy: So we've got three groups of people trained in the art of looking at skeletons and one skeleton, a male skeleton.
Ruth Morgan: So our first group excavated their grave, and when they excavated the grave, there were female clothing in the grave.
Suzie McCarthy: A pink dress, high heels, that sort of thing.
Ruth Morgan: They brought the skeleton back to the lab, and then did the sex estimation. And in that group, one person said that the male skeleton was male. Two people said it was possibly male. Five people said they couldn't determine whether it was male or female. And three people said it was possibly female.
Suzie McCarthy: So out of 11 people, only one got it right. Even though the skeleton was an obviously male skeleton.
Ruth Morgan: We then did the same experiment again, the only differences time was that the clothing in the grave was neutral, neutral clothing.
Suzie McCarthy: A pair of denim jeans, trainers and a grey t shirt.
Ruth Morgan: Same thing happened: back to the lab, skeleton out, sex estimation. And in that group, seven people said that the male skeleton was male. Two people said it was possibly male. And one person said they couldn't determine whether it was male or female.
Suzie McCarthy: This time out of twelve people, seven people got it right. The third group was a control group who didn't see the skeleton in the grave with any clothing, but just on its own in the lab. This was to see if it was the clothing causing the difference in results, or whether it was something else. For example, something weird about Mr. Skeleton himself, causing people to get the sex estimation wrong.
Ruth Morgan: So this group, we laid out the skeleton in the lab, and we just got him to come into the lab and say: is the skeleton male or female? And when we did that, every single person said that the male skeleton was male.
Suzie McCarthy: The control group saw the skeleton without any clothing and all 15 people correctly identified it as male.
Ruth Morgan: So what that was indicating is that the external factors that the participants were exposed to at the crime scene was having some form of impact in terms of what they were ultimately understanding the evidence to mean later down the line. And this is something that we call cascade bias. So an impact at one point continuing to cascade through the process and impact what we understand the evidence to me later down the line.
Suzie McCarthy: So if humans have a tendency for this sort of bias, couldn't we just remove them from the process altogether? Isn't there technology that can do the job for us?
Ruth Morgan: I'm convinced that we're going to have a lot more automation in the future. But we're not going to have a scenario where everything is done by computers and AI, and machine learning. We're going to have to have people involved because there are certain things that only people can do. So every crime is different. You need that expert to be able to be able to identify the extraneous factors that are really critical to making sure we get the right evidence and package it in the right way and ensure that the right tests are done.
Suzie McCarthy: Can you think of our example of why... Why would you use a human?
Ruth Morgan: Fingerprints is quite a good example. So in the databases that we have, you have prints that have been taken under set circumstances. So they've been taken very deliberately. That's what's in the database, but then when you're recovering marks from a crime scene, so that would be on the edge of a door or on a weapon or on an object that's had some cleaning products on it or whatever it might be, you've got marks. So they're not these nice, pristine clear prints, they're marks where they might well have been some movement or a partial mark or a mark this then had parts of it that have become very unclear. So you're often looking at a smudge to print. What we're seeing is that at the moment, the technological approaches are very good with the prints and you can get some very, very good distinctions being made. But when you're looking at smudges, for want of a better word, that's where a human approach can be incredibly valuable because an experienced examiner begins to be able to interpret: "oh, okay we're seeing a mark that has been smudged through a clockwise action. Actually, I think what we're seeing is something that's upside down if we turn it around, then maybe we can see a few more..." So there's a lot more going on. And you'll get a lot more information out of that smudge from a human than if it was just part of a big dataset that a computer system was, was looking at.
Suzie McCarthy: Okay. So humans have skill sets that can't simply be replaced by technology. And yet, we're still left with the problem of their weakness towards bias. Those kinds of decisions, particularly in conditions of uncertainty, are susceptible to these external factors.
Ruth Morgan: And I don't think you're ever going to get rid of that, because that's how our brains are wired. It's how we're able to do a whole host of different complex things. It's what makes us unique,
Suzie McCarthy: But there must be some way of overcoming this. How could those external factors be compensated for with Mr. Skeleton, for example?
Ruth Morgan: So it's not a case of eliminating those kinds of impacts, it's mitigating as much as possible. So there are a number of approaches that have been put out there in terms of how to minimise the impact of those kinds of factors. You could probably go one of two ways, there is an argument to be said for simply providing the skeletal remains to an examiner in the lab without any other information. But the issue is that often in forensic science, that isn't the question. That's not the only question you need to answer. And actually, a lot of that contextual information can actually provide really valuable clues as to what it is you're, what kind of situation you're investigating. So there are a number of different things. One is to segment that process. So different people do different parts. So one person excavates, one person does the sex estimation. Or, documenting all the potential opportunities for these kinds of extraneous pieces of information to have entered into the decision making process, so that when the conclusion is reached, there's also a clear route to that decision that documents potential sources of information that might have influenced it. Because you want to maximize the benefit of being able to see that whole picture. It's ensuring that we're getting the best out of the people and the technology.
Suzie McCarthy: We'll be hearing more from Professor Ruth Morgan next time when we'll be looking at a situation in which technology is doing too good a job. And, we'll learn about how your DNA might be on a murder weapon that you've never seen before in your life.
Made at UCL the podcast is produced by me, Suzie McCarthy. The executive producer is Nina Garthwaite and mixing support has come from Mike Woolley. We'd like to thank all our researchers for welcoming us into their labs and offices. #MadeAtUCL is a campaign that brings to life disruptive thinking from UCL. Research presented in this episode was nominated and selected because of the impact it has made on everyday life and society. This episode is brought to you from UCL minds, events, lectures and podcasts open to everyone.
Transcribed by https://otter.ai Transcript edited by Suzie McCarthy