Today’s episode is sponsored by Skillshare. Brew Brew! What do you hear when you watch this video? Wait, is that Ben 10’s Omnitrix? What’s it saying, brainstorm? Oh homie I knew it! What? Well, when I showed this to Grill he thought it said Green Needle! And I thought that it was like The Dress™. Remember? The blue-black or white-gold debate? Oh yes. That’s a classic. Maybe it’s the same thing as that Yanny and Laurel one! You remember that one? How could I forget? That is curious though. You know I love illusions and magic. Let’s find out what’s behind this abnormal auditory appearance. Today’s episode contains specific audio cues, so our sincere apologies to those who are hard of hearing. We see you. There will still be fun stuff to learn! And with that out of the way, let’s get into it! This trick sounds similar to the famous case of Yanny v. Laurel. If you’re not familiar, there was an audio clip that made its way around Reddit circa 2018 in which a single clip would be played, however half of listeners interpreted the sounds as someone saying “Yanny”, while the other half heard “Laurel”. I remember that, I remember that! Grill heard Laurel, and I heard Yanny. Laurel, Laurel all I hear is Laurel! There’s no way it’s saying Yanny. Play it again! It’s not saying Yanny. I swear to God, if any of you are hearing Yanny you’re a bunch of- I imagine many of you at home had similar arguments, and it begs the question. How can two people literally hear the exact same sound, yet interpret them differently? I thought I’d turn this over to my resident audio expert. You’re all over that ASMRtube. What’s going on here, Wisp? Well, Brew, it all comes down to frequency. Most sounds we make are made up of a few frequencies at once. Like the “yuh” and “luh” sounds share frequencies with each other. So when we hear those sounds, certain frequencies are emphasized by our brains, and we hear them more prominently than others. Our age also impacts what we hear too. Typically, adults start losing their high frequency hearing at age 65, a condition called presbycusis, but it can start developing as young as 18. A little bit of high frequency hearing loss isn’t that bad, in fact, most adults over the age of 18 are unable to hear frequencies above 16,000 Hz, and only infants are able to hear over 20,000 Hz. Ah, yes. It’s the basis of the Kids Be Gone, a high frequency crowd control… tool? weapon?... that deploys a constant high frequency tone through speakers located in strategic locations in malls, transport hubs, and public spaces to discourage teen loitering. Whoever made that needs to chill. Many militaries and police forces use the same technology to deter pirates, and pacify riots by emitting tones at such high frequencies that it can burst your eardrums, so take that how you will. But the point is that young people typically have a higher range of hearing. We can even do a quick test now! We’ll play a descending tone from 20,000 Hz down to 15,000 Hz, and you can pause whenever you hear the sound, and make sure you wear a decent pair of earbuds or headphones. And that’s the limit of your high range hearing. So when the Yanny and Laurel audio plays, depending on your age, you might hear more of either the high or low frequencies, and hear a completely different word! Not only that, but the headphones or speakers you use to listen to it can also change what frequencies are emphasized. Well, if I lowered or raised the pitch would I hear a different word? Yep! Don’t forget that our brains also influence what we hear. Professor Bharath Chandrasekaran of the University of Pittsburgh, has said that our brain will automatically take any ambiguous information it encounters and try to match it to something it’s seen before. Yeah! So when you hear sounds with elements from low and high frequencies, especially if they sound like words, your brain will pick what you hear best, and what you’re expecting to hear. So then what’s going on with the green needle brainstorm thing? As far as I can tell, you showed me the original video, but here’s one circulating across Tiktok that displayed the two phrases on screen, which changes what you hear depending on the one you’re looking at. Let me guess, is it the McGurk effect? Oh you know it’s my main man McGurk. Y’all mind McGoin’ over what that means? It’s what happens when your visual perception contradicts your auditory perception. It’s the exact same audio but depending on which visual cue you look at, your interpretation of the sound changes. The best known version of this audio illusion is referred to by researchers as this: Which means that when a B sound is uttered, with someone mouthing a G sound, you’ll hear a D sound. There are other examples of the McGurk effect! What do you hear this man saying? He’s actually saying “bah”, while the video shows him mouthing the sound “Fah”. If we look at his lips, then we can’t help but to hear an F sound where there isn’t one. It’s kind of like your brain is doing a bad lip reading. A lot of folks who are hard of hearing deal with this sort of issue on a daily basis, I love to groove and boogie, mm yeah... Great. The McGurk effect proves that we do not rely on a single sense at a time, but in fact, the integration of many senses at all times. In other words, the McGurk effect is a glitch in the nearly seamless combination of audio and visual senses. Your brain is constantly taking in information from your senses, that is, touch, smell, taste, sight and hearing, and combining them. We don’t usually notice because, even though there’s a supercomputer’s worth of calculations happening right behind our eyes, to us, reality just is reality. Speaking of which, taking what’s there and organizing it into understandable packages is actually pretty similar to what we do here. If you want to learn how to make videos like ours, check out today’s sponsor, Skillshare! It’s a growing online community of professionals, teachers, and creators all working together to curate thousands of online video classes on any topic imaginable! Just check out their website, and we can try out new skills, develop existing ones, or just enjoy the act of learning! Most of our videos are a combination of found footage, and in-house animations which we voice and edit ourselves. Penny Lane’s class, “Filmmaking From Home: Turn Found Footage into a Compelling Video” has been a great resource for our work, and if you're at all keen on picking up some content creation tips, check out her series! Skillshare is giving the first 1000 people to sign up with our link in the description for a free trial of Skillshare’s Premium Membership, after that it’s only 10$ a month! Thanks a lot, Skillshare, for keeping us curious! But wait Brew, if the world around us is all of our senses combined, why does the McGurk effect even happen? Yeah, why do our brains just fill in information sometimes? That’s a great question! Neuroscience is complicated, but researchers have some idea of how this happens. Neuroscientists Ilana Witten and Eric Knudsen argue that our brains organize information based on what is statistically “optimal”, saying that there isn’t a specific mechanical advantage to vision over other senses, but the information that we get from our eyes is categorized as the most reliable. Auditory cues change gradually as the source moves, whereas a visual cue changes instantly with the source. For example, if you close your eyes and listen for someone, you might be able to tell the direction they are from you, but you won’t be able to tell things like whether they’re crouching or standing. Visual cues can override other senses. Witten and Knudsen point to an effect known as “visual capture” to illustrate this. It’s how a non-visual sense gets drawn to a visual location, like when you’re watching this video, your brain “moves” my voice as if it’s coming from my mouth as opposed to your speakers or headphones which produces the actual sound you’re hearing. Oh, that must be how the McGurk effect works too, right? Exactly! Your brain knows when the lips don’t match the sound, and it tries to compensate by picking the most statistically reliable sense, your eyes, and adapting your other senses to match it. This is why it’s so jarring when audio and video don’t match when you’re watching something. Your brain knows something is wrong, and it desperately needs things to match up. When it hears ambiguity in pitch, you get something like Yanny versus Laurel, where it picks the most prominent frequencies. Whereas when your brain sees contradictions, you get something like Green Needle versus Brainstorm. But in both cases if you concentrate hard enough, then you can switch cues. Oh, and by the way, the original audio does in fact say Laurel. How do you know? The audio is from a vocabulary website, and Yanny was simply a glitch. Also it helps that Laurel is a word, and Yanny isn’t. What about Green Needle or Brainstorm? Brainstorm. The toy is from a children’s show—although adults can enjoy it too, who said they can’t—called Ben 10 about a kid who can turn into aliens, and one of them is named Brainstorm. The toy just rattles off each alien’s catchphrase. The reason I love illusions so much is because these amazing machines inside our heads have had millions of years to become more complicated than we could even understand, but we can still figure out ways to mess them up. It’s like pulling a prank on your own brain! Doesn’t that just blow your mind? Hey everyone, thanks for watching. Give us a thumbs up if you learned something, or even if you just enjoyed listening! Let us know other illusions you’d like us to explore in the comments, and consider subscribing if you want to see more of our videos.
