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.
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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!
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