Gillian Forrester on gesturing gorillas, babbling babies and the origins of human language

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0:33Gillian Forrester: This week on The Interface, millions of kids have grown up on camera with their childhoods turned into content. There's a new law in California that gives kinfluencers the right to be forgotten, and it could impact adults too. And an attack on Russian data centers started a rumor that all the evil disinformation bots had been deleted from the internet. But the truth might actually be a lot scarier. For our take, join me, Jess Maddox. And me, Thomas Germain, for The Interface. Listen on BBC.com or wherever you get your podcasts. You're about to listen to the latest series of The Life Scientific.

1:09Gillian Forrester: Episodes will be released weekly wherever you get your podcasts. But if you're in the UK, you can listen to the latest episodes 28 days before anywhere else, first on BBC Sounds. Hello. Have you ever thought about just how similar we are to our great ape relatives? and perhaps wondered how exactly humans evolved into this walking, talking hominid success story. Well, my guest today has. In fact, she spent much of her career studying human children alongside gorillas, chimpanzees and orangutans, building up a remarkable picture of the link between movement and communication and what it can tell us about the way our brains are developing.

1:52Gillian Forrester: Gillian Forrester is a professor of comparative cognition at the University of Sussex. Her research asks whether the roots of language lie not just in the mouth and vocal cords, but in the hands, via gestures, tool use and problem solving. Along the way, she's made some fascinating discoveries, including a surprising relationship between how our brains divide up left and right and neurodevelopmental conditions like autism and ADHD. And she's explored how subtle physical behaviours in children might offer clues about their social and linguistic skills later on. Jilly's work has taken her from Gorilla Island in Gabon to the living rooms of parents with newborn babies to Glastonbury Festival, all in the name of finding out what it means to be human.

2:41Gillian Forrester: A question that I suspect becomes particularly interesting somewhere around day four of Glastonbury. Professor Jilly Forrester, welcome to Life Scientific. Thank you for having me. Jilly, you spent much of your career are working with our closest relatives, the great apes, and you've argued that instead of attempting to teach them our language, we really should be trying to understand theirs. First of all, do great apes even have language in the way we humans usually understand it? I think language for us is quite a special cognitive capability. It has grammatic rules, syntax and structure, and we don't see it specifically in this same format in other animals, yet other animals have very sophisticated communication systems that we don't always totally understand.

3:27And with other great apes, not only are they interesting in their own right as unique species, they are a window into our past and could hold some clues about how we became the way we are today.

3:38Gillian Forrester: And on a different note, one quite remarkable similarity that your research team has identified between humans and our ape cousins lies in our response to stress. It's an An effect that you've called the nasal dip. So what exactly is it? It is actually a change in temperature in the nose area when we get stressed out that we can measure with thermal cameras. If you're nice and calm, you have even blood flow across the face, which shows up an even temperature across the face. But if you get stressed out because you're a primate, you start to have really hypervigilance with your senses. Your vision becomes better.

4:15Your hearing becomes better because all the blood rushes to your senses. So you can look out for predators. And just a consequence of that is that you've got less blood in the middle of your face and it shows up as a nasal dip.

4:26Gillian Forrester: And I believe that for people working with apes, you think this might provide some useful information. We're hoping so, because stress is a really big indicator of psychological well-being. So any apes who are in sanctuaries, who have experienced trauma, their caretakers can use this information to help them. And outside your academic research, Julie, and about as far away from the lab as one can get, you're also the curator of the Science Futures Zone at Glastonbury Festival. How do people react to science in the middle of a music festival? They come in a bit surprised. You think they might go, oh, that's not for me.

5:05And they end up staying and loving it because we've made Science Futures a really special place where science is not just informative, but it's entertaining and engaging. And it's for everyone.

5:17Gillian Forrester: And I can imagine Glastonbury must be an interesting place for you to study human behaviour. We're not actually collecting data there, but you've given me some good ideas. So, Jilly Forrester, you were born in New York, but your parents weren't American. So how did you all end up there? My parents were both Hungarians, and they grew up during war time. And actually during the Russian occupation in 1956, the borders were open for a very short period of time. My mother was 16 and she decided to leave with her best friend. My father left with his friend, a few years older than my mum. They met on the way out.

5:58They helped each other through with nothing but the shirts on their back. They were engaged by the time they got to England as refugees. And once my parents were situated in the UK, they actually stayed for 14 years. They finished their education before being relocated to New York for my dad to take on a new position.

6:16Gillian Forrester: Goodness me. And your family then moved to California, where you spent most of your childhood. And I gather that right from a very young age, you had this passion for primates. Obsessed. Obsessed particularly with chimpanzees. I grew up during a time when there was some media about trying to teach chimpanzees human language. So presumably influenced by people like Jane Goodall and Diane Fossey. Absolutely. So watching these women who were the first of their kind to actually go out and not just try to look for human traits in our ape cousins, but look at them in their own rights as these unique species.

6:56I thought this was phenomenal.

6:59Gillian Forrester: Well, you then went on to the University of California, San Diego, which is where you got your first chance to work with primates. You described it as an eye-opening experience, but perhaps not in the way you might have hoped. That's true. I worked in a psychopharmacology lab with squirrel monkeys, and they were using drugs to look at how it changed the behaviours of these primates. But it was invasive. So they were actually recording from cells in the brain, which meant that these little primates underwent quite invasive surgery. And I didn't feel like this was necessary. So while it was a good learning experience, it definitely gave me perspective on what kinds of methods were out there and what I wanted to pursue.

7:46Gillian Forrester: Well, Julia, after your degree, you took on a PhD at Oxford University to study experimental neuroscience. What did that involve? I did. So this gave me a thorough grounding in neuroscience methodology. I was putting electrodes on people's scalps. So this is non-invasive, very just surface recording, which was fantastic way to understand not just brain organization, but how it functions and how behavior is a manifestation of what's going on inside. It's like a mirror into the brain. Very cool. Well, as you were finishing your PhD, Julie, you became pregnant with your first child. So you decided to stay on in England rather than go back to the US.

8:30Gillian Forrester: And you took a career break to raise your kids. Did you miss the academic world or was family life sort of a welcome hiatus for that point? I had always wanted to be a mother. So having a child was a wonderful experience. But I have to say that I missed the academic stimulation and the challenges. So it lasted probably slightly less time than planned. Right, right. Well, you took on a part-time role as a research assistant in the baby lab at Birkbeck College, University of London. But of course, not where you really wanted to be, which was studying primate great apes. Yes, I had decided after I had gained the neuroscience background, I had good psychology and cognitive skills and neuroscience skills that I could now bring these into great ape work.

9:21And I wrote a grant application to study gorillas and their communication system from a kind of systematic, quantitative way.

9:30Gillian Forrester: And of course, that allowed you to go back and study something that you'd been passionate about since your childhood, communication in great apes. Now, specifically, this is in a group of captive Western lowland gorillas in Kent. What were you trying to find out? I was curious to understand their communication system. So rather than imposing a human communication system on them and looking for maybe vocalizations that represented earlier forms of human speech, I was working with a theory that suggested that human speech began as gestures. They were more visual characteristics. So I was looking at their postures, their manual gestures, their whole body gestures, their facial expressions, and putting all of these different channels together, including vocalisation, to see if there was any structure in the way that they were communicating with other individuals.

10:27Gillian Forrester: Well, now, while studying this gorilla family, you fell pregnant again. But I gather this exciting news wasn't particularly well received by all the gorillas that you'd been working with. Yeah, I'll tell you about Emmy. So Emmy was a Western lowland gorilla in this family group, and she was quite low in the social hierarchy of the gorillas. So when we were around and filming, she was very keen to buddy up to us and hang out. And she became kind of my shadow. So she would follow me around. We'd sit together just with this sheet of perspex between us. So you could literally sit shoulder to shoulder.

11:05And we were very close. But before I could even notice that I was showing, she started changing her behavior towards me. And she would start displaying in front of me, aggressive displaying.

11:16Gillian Forrester: She picked up that you were pregnant. She must have because she even started throwing things at me. She would start lobbing sticks and stones at me with pretty good accuracy. But she was really cheeky because she would look at me and look away and wait till I wasn't looking and then she'd lob something at me. And then as soon as I had my daughter, I brought her in and showed her off and it stopped. And she went back to normal her. I think she looked at my daughter and went, well, that's a useless gorilla. Good luck to you. And the only theory we could come up with was that she thought that I had maybe had this child with the silverback.

11:55And I had maybe cut the queue for breeding rights because she hadn't had a child with the silverback.

12:02Gillian Forrester: She basically assumed you were part of their family. I think she thought we were part. Yeah, definitely. Definitely. Well, much later in 2015, this same family of gorillas was released back into a nature reserve in Gabon. How did it go? Yeah, it was a massive deal. This was the first group that was going to have a translocation to Africa, part of the John Aspinall's incredible work to rewild great apes. Initially, it went perfectly well. They go to what's called a soft release on Gorilla Island, which is a geographically isolated small bit of land where they can get used to the temperatures, the habitat, the natural foods there.

12:45And they have a team who look after them until they feel like they're ready. And then they build a bridge between Gorilla Island and the main reserve and off they go. And they can come back if they want to and feel safe, but eventually they go off. And very sadly, a few weeks after the bridge went up, the harem of females were found dead. And still to this day, we're not sure why, but the silverback and the children survived. Potentially, this was a lack of immunity to certain diseases and a lowered immune system because of natural stresses that come with such a big change. But nevertheless, the silverback and the children have thrived.

13:25And in fact, one of the children has become the father of the first wild-born gorilla to captive-born.

13:33Gillian Forrester: To captive parents. To captive parents. Wow, that must be a special thing. That's very special. Well, Julie, back in 2010, you returned to full-time work as a lecturer in psychology at Westminster University. And alongside your teaching, you started comparing human cognition to that of other great apes. Your research here was really looking at the link between language and the way we and other apes use our hands to solve problems. How are these two things connected in the brain, language and dexterity? Yeah, there are two primary theories that I work with. One is called gestural language theory.

14:12And that just suggests that we didn't always speak with our mouths. We spoke with our hands before we spoke with our mouths and probably not just our hands, but probably our whole bodies. And as we became bipedal and our hands were freed, we started doing that a lot more. But we were also doing other things with our hands, like using tools and making things. And eventually we think that if you wanted to teach somebody how to do something, but you were talking with your hands, it became difficult. So there was a pressure for language to move to the mouth. And then there's the tool use theory, which suggests that the way that you order the sequences of actions to solve a problem is basically syntax.

14:54So you have to solve small problems in order to solve an overall goal. So that is the same as putting words in the right order to make a sentence. So we believe that actually physical syntax preceded the speech syntax. And so this is how the hands became linked to the mouth.

15:14Gillian Forrester: That's interesting. Cheers to fall savings at Whole Foods Market, home of higher ingredient standards. This Halloween, share chocolates and candies made without that spooky high fructose corn syrup. Throwing a party? Make it easy with a Barry Chantilly cake. Ready to cook pizza. No antibiotics ever chicken wings. And sushi made fresh daily. Fall gatherings never tasted better. Save through November 3rd at Whole Foods Market. This week on The Interface, millions of kids have grown up on camera with their childhoods turned into content. There's a new law in California that gives kinfluencers the right to be forgotten, and it could impact adults too.

15:55Gillian Forrester: And an attack on Russian data centers started a rumor that all the evil disinformation bots had been deleted from the internet. But the truth might actually be a lot scarier. For our take, join me, Jess Maddox. And me, Thomas Germain, for The Interface. Listen on BBC.com or wherever you get your podcasts.

16:18Gillian Forrester: Well, to try and demonstrate this relationship, you've created puzzle boxes and you brought one in for me to try. I should explain this is a thin box with a perspex sheet cover with holes in it and behind it are several shelves with cogs that you can spin with your finger. Now you've got a hazelnut that you're going to drop into the box. So the idea is that I have to work out how to get the nut from the top to the bottom by putting my fingers through the holes, pushing it around and spinning the cogs so that it falls through the various levels. I'm going to have a go, but before I do, could you just explain what a puzzle box like this has to do with language?

16:58The idea is that if syntax originated from how we solve problems with our hands, then we could make a puzzle box that mimics this problem-solving scenario. And that works for not just humans who are learning language like 18 month olds to six year old children, but it could be the same boxes that we give to chimpanzees, gorillas and orangutans. And if they can all solve these kinds of problems, then we have some evidence to suggest that syntax in the hands preceded syntax in the mouth.

17:33Gillian Forrester: OK, pass it over. You ready? I'm going to have a go. You hold it for me. right okay i'll pop it in the top pop it in the top and then you got to get it out as fast as you can right and i'll just say chimpanzees can do this in under 30 seconds are you ready steady go yeah under 30 seconds that's that's ridiculous oh lucky shot there and we're coming down to some cogs all right we're getting towards the bottom i think i'm stuck i think you're stuck you're gonna have to follow through now i failed failed i'm really sorry to say that you wouldn't make a very good eight so my phd in theoretical nuclear Paleophysics didn't stand me in very good stead at all.

18:10Gillian Forrester: My producer, I'm sure, is very pleased about that. Just in my head, my producer is saying he's delighted. Now then, you test these puzzles on both human children and other great apes. So how do they tend to fare? So our very young children who are single word users wouldn't be able to solve a complex box. This is like sentence level complexity, and that's our older kids. But every species of great ape, at least some individuals in the group, can solve the hardest syntax problems. That's incredible. So if apes can solve these kind of more complex syntax problems, then it gives us some additional support to say that physical syntax existed before we split from a last common ancestor.

18:55Right. So the way we solve problems with our hands and the way we speak is actually the same bit of brain working. And this is why, like, if you're a deaf signer or a hearing speaker, the brain doesn't care.

19:07Gillian Forrester: It's syntax by using different parts of the body. Exactly. Gillian, you're now a professor of comparative cognition at the University of Sussex. And one theme that runs through much of your work is the idea that the two halves of our brains have distinct roles, what's known as lateralisation. Now, before we get into what you found, can you explain what lateralization actually is and why we might have evolved it? Sure. Lateralization just in this context means that you might use one side of your body or your brain slightly more than the other in certain contexts. Right. So everybody probably thinks of their handedness as part of their identity.

19:51And this is tied to the way our brains are organized. So we have what has been coined a divided brain, which we think dates back to the Cambrian period, like 500 million years ago with the rise of vertebrates, or maybe even earlier, where the right side of the brain developed as dominant for fight or flight capabilities. And the left side of the brain evolved as dominant for basically feeding behaviors. So motor action solutions to get food into the mouth. So we think that all of the things that we do as modern humans kind of base themselves on these original vertebrate divided brain template.

20:35So the left visual field bias for recognizing faces and identities and emotions probably is a consequence and built on top of our ability to notice threat and danger in the environment. We should probably say that the two sides of the brain operate the opposite sides of the body. So if you're right-handed, you've got dominance in the left side of the brain. And when we talk about the left visual field, that is being controlled by the right side of the brain.

21:01Gillian Forrester: Right, right. And you've discovered something quite surprising about the people who don't have this standard profile, right-handed but left eyes, as it were. Yes. So we did find that actually the majority of the population, something like between 60 and 70 percent, do still have this. But some people don't. Some people have both of these kind of fight or flight and visual preferences for emotion and stuff crowded to the left and some have it crowded to the right and some have it reversed. Now, for kind of cognitive capabilities, it doesn't seem to matter if you're standard, left crowded, right crowded or reversed.

21:37But if you're reversed, it does seem to have an effect on people's social abilities, and they have slightly lower social scores than people who have the other organizations. And we think that the possibility is because if you have the standard brain template or one of the crowdeds, it means that for the most part, you align your behaviors with other people. So if you're a right-handed person and you're working with another right-handed person, you can anticipate their behaviors really easily because you know what to expect. If you're working with left-handed people, it's slightly different. And left-handers will know this.

22:15They're having difficulties sometimes in navigating a right-handed world. But if your visual side for recognising individuals is also on the opposite side, it means you don't align on both of these two basics, which maybe just gives you a slight offset in processing social information. And there's a higher rate of ADHD and ASD diagnoses in this group.

22:40Gillian Forrester: Right. Basically, your research seems to suggest that our dexterity and language are really tightly connected. Does this imply that you could train one to improve the other? This is a possibility. And we have some unpublished work in this area where we have done just that with some children in mainstream schools and in schools for autism. So we did some fine motor behaviours, which are just if you tap your forefinger and your thumb together and then you go down the line with your fingers. And we got the teachers to do this with their children to music, three songs, so like 15 minutes a day, and they were our experimental groups.

23:18Whereas the other children were taught to just do what we call gross motor behaviors, which was they were just clapping along to songs. And we tested their verbal skills before and after these different interventions. And we found with our mainstream school kids, it really didn't have much of an effect. But with our autism schools, we found that actually it made quite a significant difference. So by training them on the fine motor skills of their hands, they were improving their verbal output. It's possible that our mainstream school kids already were doing quite well in this area and we didn't really see a vast improvement.

24:00So these two things are just so tightly linked. And it does give us promise that what we would call motor interventions might be more effective than using actual speech interventions where you're just trying to teach more speech.

24:15Gillian Forrester: You see, I'm really fascinated by this because I happen to have two seven-month-old twin grandchildren and they're going through exactly this, you know, developing their motor skills and absorbing everything. And you're saying that the way the baby moves may even tell us something about their social development later on. Yes, you're talking about the Baby Grow Project now, aren't you? Yeah, yeah, yeah, absolutely. Yes. So what we believe is that those very early reflexive movements, these are called writhing movements that happen even before a baby's born and continue for about three months after.

24:52They're not just crazy, chaotic movements that look like the little disco dancers and everybody's familiar with the way babies wriggle. They actually have some structure and they have quality to them. So we send families a baby grow pack, which has a onesie and a yoga mat and a phone grip, and they collect video for us every week so that we can use the video to analyze if they are very diverse and use the full range of possible movements, or if they're maybe a little bit more monotonous. Because this sets the body up, not just to experience the physical world around them, but also to experience the social world around them.

25:36Gillian Forrester: But I guess there is this delicate balance to be struck here between spotting any potential issues as early as possible and the risk of misreading the signals. Sure, sure. So these are works in progress. We are working with clinicians who already use what are called general movement assessments. And they already know that general movement repertoires, the quality of them is incredibly important and associates super highly with those babies' developmental outcomes, their cognitive outcomes, their social and communication outcomes. And so what we've done is we've translated what they see into a system that we can quantify because we hope that this information can eventually be in the hands of parents who can use it as an early detection system that would just say, see your GP, go for an additional screening.

26:33Right.

26:34Gillian Forrester: Well, Julie, you've said that you treat science communication as an equal partner with your academic research. Now, if you haven't mentioned this yet, but I loved working with you recently on my BBC Two documentary, Sequence of the Brain. I also know that over the past few years, you've been involved with Radio 4 science shows, you've given talks at science festivals, and even recently at a House of Lords roundtable. Has this changed the way you think about your own research? Definitely. I have found that public engagement has higher impact than publishing in Nature and Science, for example, because I truly believe that science should be out there.

27:16It's for the people. It's for the general public. It's not just for scientists. It shouldn't be behind paywalls with journals. And if we want people to be involved and understand, we have to share it. Yeah.

27:29Gillian Forrester: I've always said, why would I want to discover something about how the world works and keep it to myself? I want to go and tell everyone about it. Surely. You've expressed that you don't think humans, getting back to, in a sense, to your research, you don't think humans are all that exceptional, that we're just great apes who did particularly well in our niche. What are we still not appreciating about the intelligence of other animals? I think intelligence is a tricky word and it brings about this idea of exceptionalism with humans. And we look at our capabilities and we think, oh, those are so sophisticated.

28:03But of course, intelligence itself means that you can thrive and survive in your own ecological niche. Now, if you were placed into a wild chimpanzee habitat, you would make a terrible chimp. And in fact, you wouldn't last two minutes. Chimpanzees are better than us at some cognitive abilities, and we never talk about these. So, for example, if you imagine on a monitor, you're given the numbers one to nine, say they're white numbers on a black screen, and you just have to touch the numbers in order from one to nine. Fine. Easy peasy. We can teach chimpanzees to do that too. Easy peasy. Okay, well, now I'm going to show you those numbers, but then I'm going to mask them with a white square, and I'm going to ask you to do it again.

28:51Chimpanzees can do that with ease when you mask them after half a second. Humans cannot do this. And so this is just showing just one example of cognitive abilities where other animals surpass us.

29:08Gillian Forrester: So they beat us at card games like Old Maid, if you remember that. Remembering where all the cards are. Put them in Vegas, right? Yeah. That's incredible. Gillie, you also run the Me Human Project, an award-winning public engagement initiative that asks people to think about what it really means to be human. So after everything you've learned from our ape cousins and from human babies, how would you now answer that question? I would like everyone to be happy with the fact that we are animals, we're vertebrates, we're mammals, we're primates, we're grey apes. and without that evolutionary history and that bridge to the natural world we wouldn't be the humans that we are today so I'm a proud great ape.

29:57Gillian Forrester: Julie Forrester, thank you very much for sharing your Life Scientific. Thank you. And thank you for listening. I'm Jamal Khalili and the producer was Alex Rodway. If you enjoyed listening to this edition of the Life Scientific why not check out some of our other interviews with leading scientists exploring everything from space travel to medical breakthroughs. You can access the whole archive of programs for free via BBC Sounds. This week on The Interface, millions of kids have grown up on camera with their childhoods turned into content. There's a new law in California that gives kinfluencers the right to be forgotten, and it could impact adults too.

30:33Gillian Forrester: And an attack on Russian data centers started a rumor that all the evil disinformation bots had been deleted from the internet. But the truth might actually be a lot scarier. For our take, join me, Jess Maddox. And me, Thomas Germain, for The Interface. Listen on BBC.com or wherever you get your podcasts.