This Technicality Episode is brought to you by Audible.
You have an incredible super power you don’t even know you
have.
Check this out, I’m gonna play 2 different videos
of me saying 2 different things at the same time.
The first time you watch it, focus on this video and try to understand it as much as
possible.
Once your done with that, rewatch the clips again and try to focus on the other video.
Even though they’re both played at the same time, if you focus on one video, I bet you’ll
be able to hear it clearly.
If you have headphones, put em on now, because it’ll make things a bit easier, but you
can also do this without headphones.
Here we go.
Woah.
I really hope that worked for you because it did for me and that was amazing.
Even though I was watching 2 different videos that, together, sound like jumbled nonsense,
if I focus on one, I’m able to actually understand that video.
This is the super power you didn’t know you had: the cocktail party effect.
Hey guys, I’m here, let’s get technical.
I went to VidCon last week, and I had a phenomenal time.
I met and talked with tons of amazing and fascinating people, but, in the middle of
one conversation I had with some people amidst a big and noisy conference room, I kinda lost
focus and just started looking around.
I know right?
I’m great at this.
And in that moment when I let my attention wander, I realized how insanely loud the room was.
Nothing against the organizers of that particular event, of course, there were just a lot of
people in the room.
And when I took in all the sounds, the voices of the people I was talking to could barely
be heard.
But when I snapped out of it and focused back in on the conversation I was having, I could
hear them just fine.
The cocktail party effect is your mind’s ability to do just that; to filter out all
of the other sounds in a noisy environment and focus in on the discussion you’re having.
If you’re an absolute mad lad, you might even be able to use the cocktail party effect
to distinguish between three voices at the same time.
If you wanna know for sure what I was saying in each of those clips, I’ll reveal at the
end of the video.
The effect was first discovered in 1953 by Colin Cherry when he was in a bit of a predicament,
and not just any old predicament.
As far as predicaments go, this predicament was a big predicament.
Predicament no longer sounds like a word.
See, Cherry was an air-traffic controller, but he wasn’t late for work allowing him
to cut a line at a hot dog stand (I really hope you get that reference), but, when he
was controlling air traffic, all of the voices from all of the different pilots coming out
of the loudspeaker was made each of them inaudible.
Thus, he decided to study human attention and the cocktail party effect, and published
his findings in this paper.
You may have noticed each voice played out of a different side of your speaker or headphones,
as to emulate the voices coming from different positions and angles.
When there were two people talking, it shoulda seemed like the voices came from here and
here, and when there were three people talking, it shoulda seemed like the voices came from
here, here, and here.
But you know who's not here? Waluigi.
This is the stuff I say in-between takes
This is done so the audio more closely resembles real world scenarios.
And this makes sense, right?
When you’re at an actual cocktail party, or any loud event, for that matter, you have
noise coming at you from all angles, not just directly in front
of you.
This is, of course, the standard hand motion to
sound coming at you; it’s common knowledge.
Not to mention, having audio come at you from all slides actually makes a pretty big difference
when it comes to you trying to decipher it.
When he did his initial study on the topic in 1953, Cherry found that it was quite hard
for participants to distinguish between the two voices when they were both coming from
head on, yet, when he split them up, it was much easier.
We’ll come back to that later.
While the cocktail party effect seems quite easy (after all, we do it all the time without
even thinking about it), it’s actually an incredibly complex mechanism, and to truly
understand it, we have to understand 3 factors: speech, masking, and attention.
First, speech.
While human speech arguably isn’t the most ideal or perfect form of acoustic communication,
it’s actually pretty good for what it is.
To understand why, we first have to understand phonemes.
Phonemes are the different fundamental sounds.
They’re made of 1-4 letters, and there are 44 of them in the English language.
For example, if I were to pick a random phrase, say, “Me me big boy,” we could break it
apart, and see how many phonemes are in it.
Me has 2 phonemes, muh, ee.
Big has 3: buh, ieh, guh.
And boy has 2: buh oy.
You know this, this is what phonics is based on *you know this matter of factly sorta way*
There are 4 ways phonemes are beneficial, as outlined in this 2015 paper by Adelbert
Bronkhorst.
Phonemes are pretty uniform across different people and different voices, they make good
use of the space allocated in your head to produce them,
they’re resistant to, but not completely immune from masking by background noise, and
finally, and more of an aspect of speech itself, the information is redundant, which means,
if you mishear a couple parts, your brain can fill ‘em in.
The last two things on that list are what make the cocktail party effect possible.
Since sound waves are fairly concentrated in one region, it’ll tend to reign supreme
and be hearable over background noises, and between redundancies in sound and redundancies
in English sentence structure, it’s fine to miss a couple phonemes and still understand
the person you’re talking to.
Sidenote: we can actually track the rate of recovery of lost information if a listener
misses a phoneme as a result of a background noise.
It tends to be 50% in real word and 20% if it’s just a nonsense word.
The percentage of recovery rises to 70-90% if the sentence is short and/or common.
Second, masking.
Remember when I said we’d get back to hearing the voices from different sides of the speaker?
Well, now’s that time.
Just because someone is talking to you on your right side, that doesn’t mean the sound
of their voice only goes into your right year; some of it also reaches your left.
This means that, regardless of how hard you try, the sounds of the different voices are
gonna mix a bit, and this was accounted for in the earlier simulation.
The process of different sounds (in this case, voices) interfering with each other is known
as masking, or, more specifically, energetic masking, and the process of trying to seperate
those sounds is known as unmasking.
There are a variety of factors your brain takes into account when identifying a certain
voice and then unmasking it from the others, those primarily being the characteristics
of the voice and where it’s coming from, but other minor factors include stuff like
timbre, linguistic variability, and other things.
Ok, so we know how speech works, and how our brain separates different voices, so the last
piece left in our puzzle is FOCUSING on the one voice.
Third, attention.
This is an interesting one, because attention has changed a lot over the years.
So gather round and make sure you pay... your respects as we discuss different theories
about how attention works.
Cherry noticed in his experiments that participants, even while they were focusing on the voice
over here, they could still, to an extent, understand and process information said by
this person.
More specifically, they could understand when their own name was said, or when the gender
or pitch of the person over here talking changed.
Out of this knowledge, two different theories rose: the early selection theory and late
selection theory.
The early-selection theory was proposed by psychologist Donald Broadbent in 1958, and
it proclaimed that very little information and meaning is actually processed from the
other conversation preattentively, except for information that really stands out to
us, like our name, a gender switch, et cetera, and the late-selection theory was proposed
by psychologist Diana Deutsch in 1963, and it proclaimed that information and meaning
is processed up to a semantic level, and if your brain deems it unimportant, it doesn’t
go into working memory, but if it does deem it important, *snaps* we’re in business
like a cat at 3am.
>> VIDEO OF GUS sliding through that door.
In 1964, psychologist Anne Treisman proposed something of a mid-point between the two models
dubbed the attenuation theory.
This theory proposed that information and meaning is indeed processed, like the late-selection
theory, but the resources your brain devotes to it are minimal, and, thus, it takes much
longer to process the information.
Finally, in 1973, psychologist and author Daniel Kahneman proposed something completely
different in his book Attention and Effort.
He suggested that attention works less like where we choose what to pay attention to and
more like something with a capacity, where instead of “I’m going to pay all of my
attention to this and none to this,” it really works like “this will take up most
of my attention capacity, leaving only a little bit left for this.”
So, which of these hypotheses are correct?
We don’t really know, and that’s because any study concocted to test these theories
tends to suffer two fundamental problems.
First, shifts in attention are poorly controlled, and, thus, hard to monitor.
Second, when we look at this through the metaphor of a “filter,” it implies the sensitivity
can be controlled as a relationship to an independent variable.
However, we have no idea what this independent variable is, or how it can be used to control
the sensitivity of this “filter.”
So, in conclusion, the cocktail party effect, or the ability to selectively listen to one
person out of a sea of noise, works because human speech allows for it, your brain can
separate (or unmask) the noise you want to listen to out of all the others, and you can
continue to pay attention to the person your talking to, as well as even interpret some
data about the people you’re not.
If, like me, you really like this sorta field of psychology (the topic of how your brain
processes information), I strongly recommend the book Thinking Fast and Slow by Daniel
Kahneman, who we mentioned earlier.
I’m listening through it right now and it is simply mind blowing, I love it so much.
And, of course, the best way to get Thinking Fast and Slow is through Audible.
Audible stands for whoops copied this from Jacksfilms.
Audible is downright the best place to get audiobooks.
You get a credit every month which you can spend on any audiobook you like, credits roll
over to the next month, and, if you don’t like audiobook, you can exchange it hassle
free.
Plus, even if you cancel your membership, your audiobooks are yours to keep, forever.
I genuinely use and love Audible.
Some other books in my library include stuff like The Tipping Point by Malcolm Gladwell
and Surely You’re Joking, Mr. Feynman, by, well, Mr. Feynman.
If you want to get your first month of Audible free, that means you get a free audiobook
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click the link at the top of the description or text Technicality to 500500
Ooh, hey, here's what I was saying in the 3-video cocktail party effect experiment. Pause the video if you wanna read more.
If you liked that, I think you’ll like my other psychology videos, like You Don’t
Know How Toilets Work and How Food Presentation Affects Its Taste, which are on screen right
NOW.
If you wanna see more, subscribe, and liking and sharing the video also really helps.
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Thanks for watching, DFTBA, and explore on.