 Hi. How are we, Emma? How are you all done? You're still all alive and here and everything. It's brilliant. That was a slightly terrifying introduction because the one thing that I'm not really doing today is presenting any new illusions, anyone who is a little bit of an auditory illusion nerd. Sorry. There are a couple of things before I get started, like housekeeping things. I'd like to get out of the way. The first one is I just want to talk about this title because I think I might actually be able to lay claim to have the worst title for any talk and the entire thing. So it's kind of like I was going for a pun, but I don't know what it was a pun on. Anyway, the second one is I've made a big mistake since I got here, which is having ideas. So the talk that I'm just about to do is not exactly the talk that I had on Friday. So the new bits, yeah, hopefully they'll work. Anyway, with those caveats out the way, I'll stop apologising before I've done anything. So, sine wave speech is the first thing that I'm going to talk about. Overall, I'll be talking about three different auditory illusions. They're basically just my favourites. I think they all give us a little bit of an insight into the mechanisms behind our perception of the world. But I just like them because they're cool, basically. So, sine wave speech. It's easiest with this one to start with an example. I've also put both audio and video in a PowerPoint presentation, so let's see how this goes. Sine wave speech sounds like this. It doesn't sound like anything. Have I got? Try again. So, hopefully, out of interest, could anyone kind of get any decipherable speech out of that sound that you just heard? No, no one. It's a clanger. Yeah, that's it. I've actually got a box of wild clangers behind the stage. If it's anyone's birthday, you come and find me at the end and you can have one. So that is an example of sine wave speech. So that is, it's generated from a recording of audio, and that audio is human speech. So, when I got into the green room before, I just asked one of the organisers to record me, you know, like a little sample that I could use for this demo. So the original sample sounds like this. No, it just moved it. This is why you auto-play your samples. That was the wrong sample. Excuse me a second. Does the laugh mean that people could understand that? Or you just like the weird sound? Booking Ben was a mistake. Actually, now that's almost prophetic. So for anyone that didn't hear that, that was... Booking Ben was a mistake. So like the interesting thing now, if I go back to the original sample, is hopefully hearing this. So could people now kind of hear human speech like sounds in... Yeah, I can see a few people nodding. So it worked eventually. So what this means is that I can make other recordings like these. Sorry guys, mouse issues. So hopefully still no one can really understand that. Or if I play this, then probably the same again. So it's good that probably no one can understand those. Because actually both of those recordings are massive spoilers for Game of Thrones. So if anyone gets out of line during the presentation, then I'm afraid we're going back to that. And anyone who's not up to date is a bit screwed. So I just quickly want to kind of get into this a little bit and tell you guys about how it works essentially. So it's time for everybody's favourite part of everything, which is audience participation. You guys feel like audience participating? Okay, that's enough of you feel like audience participating. That's not just going to be me. So what I'm going to do is show you pictures of things and see if anyone in the audience can tell me what they are. So does anyone know who that is? Sorry, at the back. So I think I heard someone say Niels Bohr. If they did, yeah. So this is Niels Bohr. So from now on, whenever you see this picture appear on the screen, I want all of you to just yell Bohr at me. Just Bohr. No Niels. So the next one is this. Can anyone tell me what this is a picture of? Ah, amazing. See, this is what I was expecting with Bohr. Apparently he's not a big enough celebrity. The last one I thought was far too easy. So I've kind of obfuscated it a little bit. Does anyone know who this is? Okay, so we've got Bohr, Sand and Cox. So let's just give this a quick go. That's just for my own entertainment, that last one. Okay, so the next one. What I want you to do is do the same thing again, but try and say all of the words without closing your mouth. Without, yes, without closing your mouth. Get it the right way round. So let's try this. Any minute? Okay, so a little bit more difficult. Next one, what I want you to do is... Hold up guys, you're ahead of me. What I want you to do this time is try and say each of the pictures as they appear whilst holding your breath. If anyone is likely to get short of breath, please don't, well, breathe. If you need to, then breathe. But it's not worth passing out for the sake of science. So with each picture, take a big breath now and then still try and say them just without breathing out. We've gone back. Keep holding your breath. All right, here we go again. Go on. There we go. Okay, so... I have a feeling that not everyone was holding their breath there because if so, you guys are really, really good at annunciating because what you should actually get from this is you can only kind of get up or a... and say, can you kind of see what I was doing there? Just trying to get a mass crowd beatboxing event going on. Just basically because I wanted to demonstrate that but I didn't want to do it myself so I thought I'd get you guys to do it. So what we've actually done there is we've made the voiced and the unvoiced parts of speech. So the voiced is when you try to talk with your mouth open without closing it and the unvoiced parts are these kind of type sounds. So, if I get, for example, the original recording of a Game of Thrones spoiler and play it like this... Everybody dies. Also, there are boobs. So... and the other one for good measure. Hey, isn't she from Hollyoaks? I wrote this talk a long time ago so I know that's like proper season one, but anyway. Incidentally, I'm not up to speed on Game of Thrones so no one come and talk to me about it afterwards. I'm like two seasons behind. So what you hear in those original recordings is both the voiced and the unvoiced parts of speech at the same time. With sine wave speech, what we've actually done is created a sound which follows the voiced part of the speech without the sort of the pts sounds. But it's not actually a recording of that sound so you can kind of tell when you listen to it it's got that clangory type vibe to it. And so the first time you heard it you would have just heard that whistling sound. But the second time you hear it you can make it out, right? So... I've got one of my next slides. I've rearranged my slides. This is going to happen every now and again. We're just going to have to deal with it. Ah, yeah. So what we've got in these sine wave speech recordings is not like we've got the Game of Thrones spoiler kind of obfuscator. I haven't put something in the way of it. I also haven't kind of blurred it out or anything. What I've done is reconstructed something which has some of the essential parts of the original recording that are not all the bits we need to be able to understand it like this. So your brain, with the knowledge of what that speech should sound like is able to reinsert all of these important bits of speech that we need to be able to understand it. So that's basically sine wave speech. And I think it's a really interesting example of how perception is incredibly subjective because it's something that we actively create all the time, basically. We're constantly doing this. We're bombarded with so much information and so much ambiguous information that we have to be able to use our knowledge about the world to try and figure out exactly what's going on. If I figure with this sort of crowd, it's worth mentioning. If anyone's interested in the sine wave speech demos, there is a piece of software and a script that you can use to generate them. It's really easy. I'll tweet the link later. How do I do it for time? Not too badly. For now, I just want to go on to the second one, which is... Oh, no, I'm not actually. Again, rearrange the slides. Can anyone tell me what this is a picture of before I carry on? So the people who are saying frog, have you seen it before or can you just see it? Is there anyone that can't see a frog? A few people. Yeah, okay, quite a lot of people. It's all right. You're not supposed to be able to. We've just got some kind of mad perceptual effect going on where people are just too good. So this photo is generated from this photo. For those of you that couldn't see it in the first place, this will probably make a lot more sense. This is just a visual homolog of the same effect that you're using your existing knowledge about the world to kind of make better sense of your perceptions. So I think that really is the last slide. It is. Okay, the next one is yes. You're just really not a fan of sine wave speech. Okay. Well, you may regret saying that because for this next bit I need a volunteer. Do you want a volunteer? Right, come up onto the stage. So just like jump up here or whatever. Amazing. So you know how the McGurk effect works? Yes. Okay, brilliant. What I'm going to try and do is essentially perform it. Okay, cool. So what we're going to do here is give you conflicting visual and auditory information at the same time. Hopefully. By the way, quick caveat. This is one of the bits that I've added and I haven't tried this before and I don't mean like haven't tried it in a talk. I mean I haven't tried this before. So I literally have a browser window open in the background with a video that demonstrates it really well. So if this goes horribly wrong you'll still get the effect but we'll explain how it works. It's not the BBC one, it's another one. Okay, so I just need to do a quick bit of setup for this performance. So are you all right doing the spoken part? Yes. Okay, so that's the word. Okay. So all I want to do... Too close to the microphone. I'll tell you when to go. Okay, can we switch to the camera please? By the way, before we get onto the camera bear in mind I've been living in a field for three days and I'm going to have to get pretty close for this to work so don't judge me. Probably use the mic. What I want you guys to do is pay attention to what you see on the screen here, however horrific it is you need to be looking at the face for this effect to work. So on the red. Bass. Bass. Bass. Bass. Bass. Bass. Bass. Bass. Bass. Bass. Bass. Okay, that's probably enough. I just really hope that some people walk past behind then. Some kind of weird avant-garde theatre performance going on in here. Avant-garde minimal techno music, amazing. Sorry, what was your name by the way? Chemical Adam. Chemical Adam, thanks to Chemical Adam. Round of applause. So I was going to say did anything unusual happen to anyone there? Did anything like related to the topic unusual happen to anyone there? Did you get any unusual sort of perceptual experiences? So did some people experience it? It felt like you heard different words on different repeats. You got a few people. Okay, so it kind of worked. Can those people just put their hands up again? And then can the people who are just being nice put their hands down because I really want to know how well it works? Okay, so it did work for a few people. For the sake of everyone else, there is this lovely YouTube video which I'm just going to steal. So this is a much better example of the same effect. So again, the sound is not changing. Between the different faces here. So we've got like 15 minutes left. Auto play. So I can play that another 15 times or we could do something else. What do you reckon? Something else. Okay, so I mean this is, you can kind of maybe see how this is related to this effect in sine wave speech that you're getting conflicting information and you have to build kind of a subjective perception out of this kind of the facial movements that you're seeing and the sound that you're hearing. And as it turns out, the facial movements are strong enough stimulus, kind of salient enough stimulus for you to kind of incorporate that into what you decide the sound is. So this is, I was looking at some stuff about this recently. It's fascinating. Apparently this can work if you are just feeling the facial movements of a person. And it's reduced in tonal languages. So I thought that was interesting. Hopefully some of you do as well. But there's, you know, I thought this is kind of great. You can do this with lots of different types of conflicting information. So I can even, this effect is strong enough that I can do it with something that you're all probably familiar with. So I imagine quite a lot of you will recognise this as soon as it comes in. But hopefully I'll be able to kind of prod your brain into having a slightly different than usual sensory experience. So, um, yeah. So I mean you can do that with almost any song with words that sound vaguely kind of humorous. If you got my sense of humor. So, an interesting kind of side effects of this demo is, I've done this, I've used that video a few times. And the last time I used it, I was giving a talk in London somewhere, and they were filming them. And they put up not all of the set, not all like nine minutes of what I was saying, but just a clip of me stood next to that. So if you YouTube searched my name, there were like two videos of me. One of them is something to do with work, and the other one is just me stood by that. So I'm unbelievably glad that this is hopefully going to end up on YouTube and give a little bit of context to that incredibly bizarre thing that's out there with my name on it. So that's the second one. The third illusion that I wanted to go on to is speech to song illusion. Now, I have a slight issue with this, which I've had to fix at the last minute. Does anyone know who these guys are? Okay, not too many of you, that's not too bad. But has anyone been listening to Domestic Science on Radio 4? Right. So you will be aware of the fact that they did exactly what I'm about to do on Radio 4 about two weeks ago. I didn't know this until about three days ago when I was listening to it on Catch Up on Demand. Having already put this together, like... Oh. To be honest, I thought that more people would have listened to it. So shame on the rest of you, listen to it. It's great. Episode one, they do so much better of a job than I'm doing. But I thought, you know what? I'm not going to let myself be bullied by this massive broadcasting corporation. I'm going to do the demo anyway, but to extract a small petty revenge out of it, I'm going to demonstrate the speech to song illusion with a recording of Steve Mould from Festival of the Spoken Nerd describing the speech to song illusion just because I felt a bit meta. So this is a recording of Steve Mould from Festival of the Spoken Nerd explaining a little bit of the background of the speech to song illusion or what it's doing. Sorry, I'm terrible with track pads. Your brain has imbued that phrase with a musical quality it didn't have before. This effect was discovered by an amazing psychologist called Diana Deutsch, who presumably had a cassette player in too much time. I'm actually just stealing that joke at the end there as well, because why not? So what I'm going to do is, incidentally my main aim with this is just to have more weird noises and repetition than the Algarave stage. So I apologise beforehand for anyone who doesn't know what's about to happen. I'm going to take a small bit of what Steve was saying there and I'm going to repeat it until you all leave. Diana Deutsch, who presumably had... That didn't repeat. For any of the less observant people. Diana Deutsch, who presumably had... I was thinking of the fish in seconds. I thought he was actually looping. So did anyone have an odd experience there when they were listening to... In the last repetitions, do you experience anything different from the beginning? You lose a bit of the sense of the content, but specifically bearing in mind that the effect is called the speech to song illusion. Did anyone have the effect that I would want you to have had? Yeah, at the back. Sorry? Yeah, and you get to a point where it sounds like it's almost got a melody to it, right? No? Yeah, okay, thank God. Because otherwise the rest of this is just not going to work. So that is, like he said, all the spoken nerd guys on the first episode of Domestic Science do a great job with that. Loads of other really interesting auditory illusions, so do go and listen to that. But I was a little bit like, okay, they've done that. I need to do something else now. So I started reading around it a little bit and tried to figure out what else I can do with that illusion. And so as you probably picked up from that recording, that was discovered by Diana Deutsch, who presumably had quite a lot of interest in these types of illusions. And so she actually apparently discovered this because she released a lot of CDs, I think, of auditory illusions. And she was editing some of her own voice and had to loop one bit for ages and this happened. I can't remember what the original phrase was. But can you imagine anything more maddening than not just that, but that with your own voice? Apparently this wasn't maddening enough, so she did a bunch of research on it. They discovered, unfortunately I can't demonstrate this because we've already heard it. I've already basically broken you guys with that repeating. But if you change the pitch of the repetitions, it doesn't really work. If you rearrange the words, it doesn't really work. Not very surprising. But they did what I thought was a really, really nice little study because they were interested to know, that everybody hear the same melody in this illusion. So they got a bunch of choral singers to come in and they played them some sample for ages until they hated the experimenters. And then at the end, they asked these people to sing back to them what they heard as the melody in this sample after they'd heard it so many times. And they overlaid them all. And they found that people did seem to hear the same melody. So I thought maybe we could try the same thing. I mean you've been fairly gracious with your audience participation now so I'm just going to push you to like breaking point because I thought we could do a bit of auditory illusion karaoke. So I mean some of you might be thinking oh you know I just can't quite remember what it is. Diana Deutsch who presumably had... So that was Diana Deutsch who presumably had... I don't know why that's cutting off too late. Anyway, it doesn't matter. So just in case anyone is not completely sick of hearing that and it's completely lodged in their brain, incidentally I've literally been walking around with this in my head for two days, it's awful. So sorry. Here are the words if anyone wants to remind themselves before we do a sing-ong. But this will be the end of the talk. So it would be really, really nice if on the count of... on go, right, because this is always a mistake. Three, two, one, go. If people could sing along with one last repetition of this just to see if we all got the same melody. So three, two, one, go. Diana Deutsch who presumably had... Beautiful. I mean, yeah, I think I heard it. Did you guys hear it? Did that sound right to you? Okay, perfect. So thank you so much for actually getting involved in that because I was slightly terrified when I put that together that nobody would do it. So you guys are awesome. I've got a few minutes for questions at the end if anyone wants to know anything more. But that's it. Thanks.