The Life Scientific: Julia Simner

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1:27of the senses is known as synesthesia. And it's the rich research world of my guest today, neuropsychologist Julia Simner. Julia runs the Multisense Lab at the University of Sussex. And over the last 20 years, she's pioneered research into understanding how special brains process our sensory world in special ways. She's discovered links to autism and to different personality types, as well as a number of previously unknown sensory differences. Julia describes her career and her life as a series of swerves or sliding door moments that have led her to study the subject and the people she's passionate about.

2:03She says that the more she looks for these unusual traits in us, the more she finds, and that maybe one day we'll all be able to map our own sensory differences. Professor Julia Simner, or Jules as you prefer to be called, welcome to The Life Scientific.

2:18Julia Simner:Hi Jim, thank you so much. It's really lovely to be here. I bet a lot of listeners at home will be wondering if they have synesthesia, and I certainly am. Is it possible to tell if I might have synesthesia? Well, there are rigorous methods that we would run in the lab, but just informally in a chat, I could probably get a very good idea just by asking you four key questions, really. Jim, have you always thought that letters and numbers have their own individual colours? OK, well, certainly with numbers for me, not with letters. For example, I think of number two is green and number three is red.

2:53But I think that's because I'm remembering the colours of the rockets on Thunderbirds. I think Thunderbird 2 was green, so I'm not quite sure if that counts.

3:06Julia Simner:Well, there are some ways in which experience can play into genuine synesthesia, but let's push this a little bit further. And also let's talk about letters and numbers. So could you tell me what colour you would give to the letter O if you had to give it a colour? I would probably say if I had to give it a brown. And what colour would you give to the letter I? Yellow or green, maybe pale green. And then similarly, what would you give to the number zero? White or black. OK. And what would you give to the number one? Well, zero is white and number one black. Zero is white and number one black. OK, so here's something really interesting that I did not expect.

3:45Julia Simner:So the O and the I test is useful because O and I are diagnostic in a way. O and I tends to pull apart the pack. So a non-synoste will tend to say that O is orange, for example. But a synoste would tend to say that O was white and I was black. Now that O and I test carries over to numbers with zero and one. And what colour did you say was zero? You said it was white and you said that one was black. That gives me pause for thought straight away. The third test is a test of descriptive richness. Why don't you give me the colour of two? Dark green. You're bordering on passing and failing the third test, which is on descriptive richness.

4:27Julia Simner:So when a synesthete gives a colour, they are at pains to tell me the exact shade of that colour. So a long description like, oh, the kind of purple you get when you cut in half. an old beep boot. Oh goodness me, okay. You know, it's got flecks of red, but really it's kind of purple in a deep sense. And the last one is a consistency test. So the way we do it is that we ask people to come into the lab or we give them an online test and we give them the letters of the alphabet and the numbers in a random order. And we say, please choose your colour for each of these letters and numbers. And they are given in a random order and people pick out their colours.

5:02Julia Simner:But then when we get to the end, we say, OK, well done. Surprise. I'm going to ask you to do it again. And what we find is that the second time round, the non-Synosteques are completely inconsistent, whereas the second time round, the Synosteques are highly consistent. Now, unfortunately, we elicited some colours from you yesterday without you knowing to expect it today. But we asked you for your letters. So you said yesterday that O was purple and today you've said it's brown. But had I asked you about the colours yesterday for numbers, I rather suspect you would have been consistent over time.

5:37So what would your diagnosis be?

5:40Julia Simner:It's quite tricky, Jim, because you've passed the O in the I test. You've passed the life experience test. You weren't particularly rich in your descriptions. So I would say, all things considered, I would come away thinking you potentially do have some form of number colour synesthesia. Who knew? Well, how cool is that? How cool is that? brilliant well fantastic um is it a continuum or is it an either or you either have it or you don't well it's definitely a continuum because even people without synesthesia can have synesthesia like experiences but there is a point when it flips into being synesthesia and that is really where it comes to having conscious awareness and sort of being aware of it throughout your lifetime it's a bit like i don't know if you've ever been on that bridge between america and canada halfway through there's a flag change and it's a bit like that we can all line up on the on the bridge and be slightly more and more and more synesthetic but there's a moment in the middle where you flip into synesthesia.

6:37Okay Jules Simner let's find out what set you on the path to becoming this pioneer in sensory science. As I understand it you were 16 planning on eventually studying chemistry at university when you experienced what you call your first serendipitous swerve. You won a scholarship to go to the Sorbonne in Paris. So you swerved away from science to linguistics. How did that scholarship come about?

7:02Julia Simner:Well, I think I was in the lower sixth and I had always loved chemistry and I was always dead set on being a chemist. I had a fantastic chemistry teacher, but I also had a great and slightly intimidating but fantastic French teacher and I loved French and he suggested that I enter this scholarship competition which took me off to Paris at the age of 16 to study at the Sorbonne. I spent a whole glorious month in Paris and I came back utterly convinced I wanted instead to do French. So that was it. Chemistry had gone, you wanted to do French and this is where you encountered another swerve, perhaps more of a sliding door moment.

7:37You'd set your heart on going to Oxford to do French but you didn't get the grades. But a path opened up that defined your life both personally and professionally.

7:47Julia Simner:Well yeah so I'd applied to Oxford and they'd given me a place but I needed to get an A in my French A level, also A's in my chemistry and maths A levels and results day came and I'd done it in the maths and chemistry but not in French and so I was rejected from Oxford but my French teacher questioned my grade and actually I had got an A so Oxford were contacted, they gave me my place back but it was for a year later. And it's this delay that ironically caused a number of doors to open for you? It had the biggest impact you can ever imagine. And I've thought about this over the years. So if someone had not pressed the wrong button, I would not have gone to Oxford a year later.

8:27Julia Simner:I would not have overlapped in my final year with an American Canadian grad student who was there for one year only. I would not have gone with him to Toronto for an extended holiday. I would not have found myself at University of Toronto doing a master's. I would not have taken a fantastic module in psycholinguistics from an inspirational lecturer, which flipped me into psychology. I would not have returned to the UK to work with his colleague in Sussex. And so I would never have met my husband. We would never have had our children. I would have a different house, different husband, different kids, different dog.

9:02Julia Simner:Everything would have been different. I mean, we can all probably look back and see these moments in our lives where had it not been for that, this wouldn't have happened. but it's incredible that that set you on a path that was completely unexpected. You say you did your master's in Canada, you came back to do a PhD in psycholinguistics, but you got drawn into the world of synesthesia by your colleague Jamie Ward, who wanted your help on an intriguing case. That's right. Our first case was a chap called James Wannerton. He's now the current president of the UK Synesthesia Association and James tastes words.

9:38Julia Simner:We were asking a simple question, which is for this person who tastes words, why do some words taste of mint and other words taste of bacon? It looks very random on the surface. But when we ran the linguistic analysis, we found out that there's this beautiful, complex linguistic system that's driving the associations. And that was really my first exposure to synesthesia. And this patient you were looking at, what I find fascinating about the the flavors the foods that he attached to the sounds of words toffee jelly beans mashed potato why these foods what and what does it tell us about the development of synesthesia the first thing to say is that these flavors that james experiences he says they're like having different droppers in the mouth and so the word julia triggers the taste of fruit sweets he very much avoids calling me jules because the word jules tastes of something really unpleasant he's too lovely to tell me what it is.

10:31Julia Simner:He says it's porridge. I'm pretty certain it's actually saliva. And what it tells us about development is that synesthesia is kind of crystallising during childhood. When we look at the tastes that flood the mouth, it's not just any taste. It's first of all tastes that are tied to James' diet. We had his mother fill out a dietary questionnaire about his childhood and we were able to show that the tastes that flood his mouth in synesthesia are significantly tied particularly to his childhood diet. So he has lots of 1970s foods. He has like processed peas and minced beef and onion and oven chips and things like that.

11:08Julia Simner:Conspicuously absent are alcohol, olives, the kind of taste that an adult would be exposed to. So that's the first clue that it's developing in childhood. The second clue it's developing in childhood comes from the linguistic analysis. Because over time, over a bunch of studies, what we were able to show is that what happens to the young synesthete is that tastes come to be associated with food names. So, for example, the word peach begins to taste a peach, but then the taste ripples out to other words similar in the vocabulary. So suddenly reach starts to taste a peach and eventually a very distant word like electricity could taste a peach because it has an E sound in it.

11:48So it's the sound of the words rather than the meaning they attach to.

11:52Julia Simner:It's mostly tied to phonemes and phonemes are the speech sounds. For example, words with E taste of peach, but words with G taste of cabbage. Well, Jules, this work you wrote up as a paper published in the prestigious journal Nature in 2006, and it really caused a stir. It even made the front page of the New York Times. And also at the time, researchers began to do MRIs, magnetic resonance imaging of the brain. Did those early scans provide any answers as to why some people have synesthesia or were there different theories? The brain imaging onset was so important because when I first studied synesthesia, the entirety of my talks would be trying to persuade people it was genuine.

12:33Julia Simner:But then as soon as we have these lovely brain imaging pictures of the brains of synesthetes, my talk could begin by saying, look, synesthetes' brains are different. When synesthetes are reading black and white letters and numbers, the colour regions of their brain are firing up. The wiring was different. It was more wiring, for example, near colour selective regions. And then fast forward to present day, some work I've done that Jamie's led. The brain works a little bit like a railway map. If you look at a railway map of Great Britain, you can see these hubs, right? London's obviously a hub and Manchester is a hub and Liverpool is a hub.

13:06Julia Simner:Lots of train lines go into there and then fork off in different directions. And the brain's a lot like that. It has these hubs, but the brains of synesthetes have fewer of these huge central hubs. they're much more likely to have connections that bypass the hubs and speak directly to different regions of the brain, if you like, without having to go through the hubs. So that explanation sounds like the sort of thing that a neuroscientist would say. It's to do with the structure of the brain and its connectivity. But there are other theories out there as well, depending on your field of research.

13:37Julia Simner:A developmental theory might be what's called the neonatal synesthesia hypothesis. So a neonate is just a newborn. And this theory is based on the fact that one thing we know about neonatal brains is that they're very hyperconnected. So there are a lot more connections in a neonate brain than there are in an adult. And what happens is in the normal progress of growth and development, something called apoptosis, which is a kind of pruning. You prune away all of these extra connections. Cell death, basically. Cell death, so that adults end up with fewer connections. Now, since we know that adult synesthetes have a few more connections, the idea is that their neonatal brain was not pruned so effectively into adulthood.

14:19Julia Simner:And then I guess the evolutionary psychologist might think in terms of why would we have synesthetes in the world? And I think the answer to that comes not so much from what synesthesia is in its heart, but what synesthesia brings with it. So one thing we know about synesthetes is they have certain profiles, certain personality profiles and cognitive profiles. And all that really means is that if you have synesthesia, you tend to be a bunch of other things, too. You tend to be super smart. And we found that child synesthetes have significantly better vocabulary, better spatial processing, better memory for numbers.

14:56Julia Simner:They're higher in creativity. So having synesthesia brings a package that you would really want. They have an evolutionary advantage. They have an evolutionary advantage. So just one simple example is that synesthetes are very good at colour memory. And what would you want if you were early man? You would want to know where's the bush with the berries. Synesthetes can perceive colours better. so they would spot the berries and then they would remember where the berries were. So with the benefit of hindsight, which of those different theories would you go for? Oh gosh, I would have to say all of them because they're not in conflict with each other.

15:30Julia Simner:They're different pieces in the jigsaw. I also get the impression that to some extent you were in the right place at the right time getting into such a new field of research when there still wasn't much known about it back then. But you have led the research that really established just how prevalent synesthesia is. Yeah, so the prevalence of synesthesia was interesting because before some of our studies, the estimates of prevalence were very, very, very, very rare. So we set about conducting the very first screening study. Through that, we were able to see that the prevalence is actually at least 4.4 % with an equal ratio of men and women.

16:05Julia Simner:So around one in 23 people at least have synesthesia, which is not insignificant. That's really interesting. But I gather that these sensory differences run in your family. You only found this out by accident and to your surprise, your mum has synesthesia. Yeah, that's right. About 20 odd years ago, when I first started studying synesthesia, my mum happened to ask me what research I was doing at the time. And I said, oh, well, I'm studying this really interesting population. And they would think, for example, that Tuesdays are green because you can also get it for days of the week. And my mum said, well that's silly isn't it because everybody knows that Tuesday is grey with that tweedy texture and I was gobsmacked because I don't have it and then I went on to just coincidentally marry a synesthete.

16:53So your husband's also.

16:54Julia Simner:My husband has synesthesia. Weird coincidence. Yeah and our children have an interesting mix. Half of them have synesthesia and the other half have something that's almost the opposite of synesthesia that I have which is something called aphantasia. Right. So tell me about that. Put simply, aphantasia is an inability or a weakness in generating a picture-like representation in your mind. So if I were to say to you, think of your house, your front door, most people can generate something in their mind that looks a little bit like a picture. Sure. People with aphantasia cannot do that. So I can't do that.

17:27Have you never been able to do that?

17:29Julia Simner:Well, this is an interesting thing. So the first thing to say is I had absolutely no idea I had it. But about 10 years ago, I was at Edinburgh University working there and I had just interviewed a synesthete. I went to the coffee room. I met a professor colleague of mine and I said, Bob, this is really interesting. I just interviewed a synesthete and it turns out they can make pictures in their minds. And Bob said to me, Jules, everybody does that. And I said, no, no, you don't understand. They make a picture in their mind. And Bob said, everybody does that, Jules. And that's when I realised something was quite different.

18:00Your mum has synesthesia, you have ephantasia. Are these conditions inherited? Are they genetic?

18:07Julia Simner:Yeah, I think they are inherited. There are certain inheritance patterns, so it's quite hard to find cases of fathers transmitting to sons, but you can find it more easily fathers transmitting to daughters. And what's interesting is with synesthesia, for example, what passes down is the predisposition for any kind of synesthesia. So mums with tasty words might have sons with coloured letters and sisters with coloured music. Right. Now, you've also found a link with autism, but not all synesthetes are autistic and not all people with autism are synesthetes. So what is the connection? So there is a link and we think that a mediator may be a trait called sensory sensitivity.

18:50Julia Simner:So sensory sensitivity is when you feel overwhelmed by your senses. If you're somebody who can't go into a perfume shop, you may have olfactory sensory sensitivity. If you don't like supermarkets because the lights are too bright, you may have visual sensitivity. We know that sensory sensitivity is high in people with synesthesia. It's also almost a defining trait of autism. We're going to come back to this increasing understanding in a moment, but I want to ask about what you call your next major swerve, because two things happened at the same time. One was your research into misophonia, where people find certain noises more than just annoying, but actually distressing.

19:29And then the other was your son falling ill. How are they connected?

19:34Julia Simner:Back in 2019, I was contacted by a philanthropic agency that was interested in promoting research into misophonia, which is a kind of hatred of certain sounds like chewing and tapping. At the time, there wasn't a lot of research. So from that point onwards, I started to study misophonia. And at the same time, completely coincidentally, my son fell ill. He had a clutch of surprising symptoms. He was suddenly incredibly thirsty. He was not getting any sleep because he was up all night popping to the loo. His eyesight got a bit fuzzy and things were screaming out in my mind. These seem to be the symptoms of diabetes.

20:15Julia Simner:And I took him to the doctor. And surprisingly, when you go to the doctor with that suspicion, you get an instant test. So the doctor instantly told us he had diabetes and needed an ambulance. and actually at that moment I could hear somebody in the room next to me saying no, no, no, no, no and I realised it was me. I was so shocked. I disassociated for a moment. It was very shocking. His life has been changed by that profoundly. For example, in the six years that followed, he had to stick a needle in himself 15 ,000 times. So you have to give blood tests and injections all day, every day, 250 a month, 2 ,500 a year, so on.