EEG shows brain can simultaneous encode two speech streams

journals.plos.org

202 points by giuliomagnifico 10 hours ago


NalNezumi - 5 hours ago

Related, but this reminds me of the story by Richard Feynman [1] when he practices counting up to 60 seconds in his head, and after many experiments around what he can do simultaneously conclude that he can simultaneously count and read but not speak. Later sharing this to John Tukey, he's told that Tukey can't read while counting but could speak while counting.

Turns out Tukey is visualizing looking at a tape, while he counts, while Feynman imagined himself talking to himself, so he couldn't speak while counting but Tukey couldn't read while counting

>By that experience Tukey and I discovered that what goes on in different people's heads. when they think they're doing the same thing - something as simple as counting - is different for different people. And we discovered that you can externally and objectively test how the brain works: you don't have to ask a person how he counts and rely on his ownobservations of him-self; instead, you observe what he can and can't do while he counts. The test is absolute. There's no way to beat it; no way to fake it.

>It's natural to explain an idea in terms of what you already have in your head. Concepts are piled on top of each other; this idea is taught in terms of that idea, and that idea is taught in terms of another idea, which comes from count- ing, which can be so different for different people!

>I often think about that, especially when I'm teaching some esoteric technique such as integrat- ing Bessel functions. When I see equations, I see the letters in colors-I don't know why. As I'm talking, I see vague pictures of Bessel func- tions from Jahnke and Emde's book, with light- tan j's, slightly violet-bluish n's, and dark brown x's flying around. And I wonder what the hell it must look like to the students.

[1] https://calteches.library.caltech.edu/3591/1/Feynman.pdf

a_gopher - 6 hours ago

If reading aloud a children story, you may notice you are able to maintain an independent unrelated train of thought. While doing so, I notice that occasionally extra mistakes can "leak" into the story telling - e.g. you read a single word incorrectly, maybe substituting a word from your other train of thought.

Qem - 10 minutes ago

Echoes of the bicameral mind[1]?

[1] https://en.wikipedia.org/wiki/Bicameral_mentality

subhro - 9 hours ago

As a pilot and a radio officer, I have always been able to process and service 2 audio streams simultaneously. So not surprised with this finding.

alexpotato - 2 hours ago

There is an interesting point about this from animation.

Imagine you are seeing a pendulum clock and it makes a "tick" on one extreme and "tock" on the other.

When they first started doing animation + sound they noticed that if you play the "tock" sound at the exact same time the pendulum hit the extreme, people would think it was delayed.

Research showed that humans required a small amount of time to "context switch" from one stimulus to another. I think it's about 1/16th of a second.

Some interesting other observations about time perception here: https://en.wikipedia.org/wiki/Time_perception

DrScientist - 7 hours ago

If you couldn't process multiple streams ( audio/visual/other senses ) how would you ever be able to monitor the background for danger and context switch?

There is a difference between conscious experience and what's going on in the background.

lokimedes - 8 hours ago

Many mindfulness practices seem to direct attention at two place at once, to quiet the inner voice. Perhaps this relates to more than just speech, but to attention itself. George Gurdjieff's "The Fourth Way" deals with self remembering, and his pupil, P. D. Ouspensky, has a very vivid description in [1] of how focusing on two things at once leads to a changed state of consciousness, that seems like meditation, and comes from the saturation of the two streams of attention.

[1] https://en.wikipedia.org/wiki/In_Search_of_the_Miraculous

chrisbrandow - 4 hours ago

Famously, the Apollo Mission control team learned to handle multiple conversations stream simultaneously. The side effect was that going to cocktail parties was a nightmare, because they couldn’t turn it off.

ChrisRR - 6 hours ago

I had assumed this was already well known.

My issue is that I can't stop processing other speech streams. It seems other people can tune out conversations around them when talking to a person but I have to hear every word

dr_dshiv - 8 hours ago

“Bilocation” was one of the legendary superpowers of Pythagoras (he was miraculously able to lecture in two cities at the same time).

Whenever I’m in multiple conversations at once in a social setting, I think of Pythagoras

saidnooneever - 5 hours ago

ask any dj who doesnt use modern sync tools and they will tell u, u can follow 2 entire songs out of sync of eachother fine, it takes practice but your brain can get used to these kinda tasks. (ofc very unscientific here :D)

adverbly - 5 hours ago

I wonder if parallel processing is related to musical training or ability.

I've always been jealous of people who can play the drums and sing or play piano with both hands and a foot while singing.

seoulbigchris - 2 hours ago

I knew a few ham radio guys who could copy Morse code at greater than 20 WPM and simultaneously carry on a conversation.

mulhoon - 5 hours ago

Anecdotally, I have 3 young kids who sometimes all talk to me at once. It's impossible to process, but with 2, I've noticed it IS kinda possible process.

t23414321 - 8 hours ago

Then it is known that if you play to someone with small delay what he says he will be lost on both - so he can't think about and listen to what he is saying if it's not one stream.

SwtCyber - 4 hours ago

This seems potentially useful for attention-steered hearing aids. A system that waits for complete disengagement from the old speaker may react too slowly

runtime_lens - 8 hours ago

This makes me wonder how much of paying attention is really prioritization rather than filtering everything else out. We probably process far more than we're consciously aware of.

moezd - 7 hours ago

Yes, and you can also write two different sentences using two different pens in your hands.

londons_explore - 8 hours ago

Listening to two talkers at a time is certainly doable...

As is talking whilst listening to another conversation - eg. Giving a lecture whilst eves dropping on the people talking at the back of the lecture theatre.

However, having a two way conversation with one person whilst listening to another is really hard.

Not sure why.

broccoluvr - 8 hours ago

you guys telling me you still listening to only 1 podcast at the time?

latentframe - 8 hours ago

The simultaneous neural representation is very interesting result here

mrbnprck - 3 hours ago

Humans are born with two ears anyways, right?

thelastgallon - 7 hours ago

"humans have only one language processor" -- this is what I remember from Patrick Henry Winstons lecture

ivanstepanovftw - 3 hours ago

Of course, because we have two ears.

alkyon - 6 hours ago

The same is true for music, otherwise canons and polyphony wouldn't work.

dboreham - 2 hours ago

I read the paper's abstract. They're not actually claiming what commenters here think they are. They're saying that there's some sort of pipeline processing for the task of "listening to speech" and when the subject switches focus from listening to one speaker to another, that pipeline has to drain. And the new stream pipeline has to get loaded up. Not actually surprising when you think about how it would have to work. The same thing likely happens with vision.

awestroke - 9 hours ago

This is maybe only tangentially relevant to the linked study, but I've noticed I can read aloud from a book on autopilot while thinking about other things or even thinking back on past conversations. I could not do this a few years ago, but now it happens on its own. I wonder how that relates to attention and speech streams

vanderZwan - 6 hours ago

Come on guys, the contribution of the research is that it made measurements of how the processing of multiple inputs is represented in EEGs, not whether or not we can handle multiple inputs. Stop acting snarky, it just shows you didn't read beyond the headline.

fortran77 - 3 hours ago

I do a form of this all the time and I've always wondered "how." I can copy Morse Code--hearing the code and writing it down--while carrying on a conversation with someone else. I'm only "encoding" it, in that I have to read it to know what I just copied. The process of hearing a letter or word in Morse and moving my hand to write it has become so automatic that I can do it while having a live conversation with someone in the room.

It would be interesting to know what's going on in my head with an EEG or FMRI...

bitwize - 5 hours ago

My wife's brain could probably do that. I'm not so sure about mine.

j45 - 8 hours ago

The DJ is explained.

throwawaysjskdk - 7 hours ago

yep, my wife does this routinely

skor - 9 hours ago

parents tend to yell at the same time and it needs simultaneous processing

nttylock - 6 hours ago

[flagged]

jimbob45 - 7 hours ago

If you can listen to someone play the piano with two hands, it’s a short hop to get to speech.