
Why are conversations limited to about four people? - benbreen
https://www.sciencedirect.com/science/article/pii/S1090513818301491
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sp332
Because otherwise you have to wait too long for your turn to speak, and you
start whispering to the person next to you.

~~~
rebuilder
To emphasize the point, you end up needing to listen to other people instead
of having other people listen to you. This is a big problem with discussions,
the need to show your own worth easily overrides the value in having an actual
discussion.

~~~
mixmastamyk
This is true, though not everyone is worth listening to, and not on $RANDOM
subject.

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stephengillie
I've always preferred groups of 2-6 people. Many board games are made for
groups of this size.

On one side, humans can mentally cope with 4-6 objects at most - as though we
have 4-6 memory slots, which is reasonable given that we have 4 limbs.

On another side, network effects of nodes on a grid become unmanageable above
about 6 nodes - a group of 6 people will have 36 one-on-one interpersonal
relationships to manage.

~~~
api_or_ipa
> On another side, network effects of nodes on a grid become unmanageable
> above about 6 nodes - a group of 6 people will have 36 one-on-one
> interpersonal relationships to manage.

Network effects grow surprisingly fast. Between 2 people there's only 1
bidirectional edge. Between 3 it's 3 and between 4 it's 6.

    
    
      | people | edges |
      |--------|-------|
      | 2      | 1     |
      | 3      | 3     |
      | 4      | 6     |
      | 5      | 10    |
    

Intuitively, this is important because in a conversation, each member must
project and rationalise each other communicator's response to a message. In
other words, each member must be cognisant of every other members response to
every message. Between a few people that's manageable, but the combinatorics
really grows for n >= 4.

~~~
bmm6o
> _this is important because in a conversation, each member must project and
> rationalise each other communicator 's response to a message_

Do they, though? Maybe I participate in conversations differently, but trying
to unravel how A interpreted B's comment is not something I would do.

~~~
hortonew
It's all I do. It's the only way I can understand if my next comment will
offend or work as a joke or if I'm posing an interesting topic. It's what
makes conversations so draining to an introvert I feel. The more people, the
more I have to figure out what I can say to be ok with the group at hand.

~~~
bmm6o
As I posted below, there is a difference between observing how different
people react to a particular comment (O(n)) and observing how different people
react to a particular comment based on who it's from (O(n^2)). I'm mostly
trying to question the idea that there's anything quadratic in the number of
participants going on here. Are you sure you're saying that the work you do is
quadratic?

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oldmancoyote
An abstract is to summarize the results of research not to tease the reader.
That's why I flagged it.

~~~
jey
Yeah, feels like the editors dropped the ball on that. Hopefully they'll fix
it before the final version.

Anyway, here's a link: [https://sci-
hub.tw/10.1016/j.evolhumbehav.2018.09.004](https://sci-
hub.tw/10.1016/j.evolhumbehav.2018.09.004)

~~~
winningcontinue
thanks. was wondering how could something upvoted this high be behind a
paywall without anyone asking for the paper itself. It's like people read the
abstract and choose to discuss what they will.

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tylerjwilk00
The problem I see with larger group discussion is that the idea permutates far
enough from the original idea after 4 turns that a participant's response to
the topic may no longer be valid in the new discussion context. It can be very
frustrating to have to unwind the progress to an early point for the input to
be valid.

~~~
jschwartzi
This is usually my experience, where if I'm with more than 3 people I stop
talking because the idea I have is no longer relevant by the time there's an
opening for me to say something.

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logfromblammo
I always thought about this in terms of individual conversational
coefficients. Each separate conversation consumes a total conversational
coefficient of 1.0 from all sources. Go above 1.0, and some people don't get
to have their say. Go below 1.0, and there may be uncomfortable lulls.

Each person has a range of conversational contributions that they may feel
comfortable with. A good university lecturer, radio show host, or stand-up
comedian, for instance, might be able to sustain a maximum of 1.0 all alone
for hours at a time. Someone with an inflated ego might not feel comfortable
dipping below 0.5 for any length of time, whereas an introvert might range
between 0.0 (pure listener) and a peak value they cannot sustain for long
outside of a narrow range of topics.

So establishing the most efficient number of conversations, and their
participants, becomes a form of the backpack problem. A conversation group can
only achieve its highest efficiency of some people aim to fulfill different
roles. Some participants are bulky and heavy, some are spongy and flexible,
and others are small and light.

There's the baseline talker. This is likely the person with the highest
sustainable coefficient. They drive the conversation. Then there are
responders, who need to have a wide, tunable range of coefficient. They top
off the conversation to 1.0 by adjusting their output to an appropriate value.
There may be interjectors, who pipe up with a witty quip or relevant factoid
every now and then, aiming for high return on low coefficient. There may also
be swappers, who participate at a low level in multiple conversations,
flipping to whichever one seems to have a lower coefficient, but less able to
sustain higher coefficients than a responder. Sometimes there is even a
gestural participant, who mainly contributes to the conversation with non-
competing visuals rather than interruptable speech.

So having a single conversation with more than six people is easy. You kick
out the baseline talker, get two responders to drive the conversation instead,
and fill up the rest of the group with interjectors. This happens all the time
in tabletop gaming groups, where the game itself adds a baseline coefficient,
and the typical participant has a low maximum sustainable coefficient. Some
people just don't want to talk much, and the game can create a structured
conversation that pulls lower-coefficient players up enough to make the group
reach 1.0 .

------
elif
for me it is an NP-hard-like reasoning. I'm not only concerned with my effect
on the 3 other participants, i'm concerned with each participant's effect on
each participant.

~~~
gnulinux
I agree with this. I also believe this is why socially normal (i.e. not
socially awkward, not shy) people can have problem talking in crowds. Needs
more cognitive overhead to analyze what words may cause what on certain
people.

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dragontamer
There's a reason why Roberts Rules, and other parliamentary procedures exist.

Once you get to ~10 people who all want to input something into the
discussion, its completely and utterly impossible to move a discussion forward
without a set of rules. Normally, one person who yells the loudest and ignores
the most people eats up the entirety of conversation space.

As such, basic rules are invented. In Roberts Rules, its one-at-a-time, and at
most contribute 2-times per any particular subject, at roughly 10-minutes
maximum per person. The "Chairperson" controls the discussion to ensure the
rules are applied equally to everyone, so that everyone gets a turn. If
possible, the Chairperson is supposed to choose an order of people's speaking
turns so that both sides of a discussion alternate back and forth (pros, then
cons, then pros again. Etc. etc.).

Its slower, but it scales better. The unfortunate effect is that most people
don't understand the point of Roberts Rules or Parliamentary procedure (there
are many sets of rules, Roberts Rules are just the most common in the USA), so
most people just see it as unnecessary set of rules that slow down a
conversation.

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woodandsteel
When I have a conversation, I like it to be back-and-forth: I say something,
they react, I react to that, and so on, with reactions being things like
asking a question, making an evaluation, saying I have had something similar
happen to me, making a funny comment, and so on, so we go further and maybe
deeper, a process I find rewarding.

The more people, the less often I get to react, and so it gets less enjoyable.
On the other hand, with some groups we are on the same wavelength enough that
a third person's reactions to the second person are enjoyable to me, too, so I
am happy to just listen to their back-and-forth, at least for a while. Ditto
if it is a subject being discussed that is really interesting.

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eithed
While yes, you have to get your turn to speak, there are sometimes situations
where you don't need to speak to communicate. For example in my TS raid group
while there are always speakers, I prefer to write on chat and can communicate
even when somebody is speaking - while I can follow the conversation that is
happening between 4 speakers I can partake in the discussion and can
communicate with other verbal/nonverbal participants. While my points might
get omitted in the discussion, or can have a delay to get picked up it allows
people that didn't get their turn to speak to get into the "conversation". In
that sense the problem is not communicating with 4 people - the problem is
getting your turn.

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munificent
I got halfway through, which I think gets you to the answer to the money
question of what's special about four. Here's my attempt to summarize:

There are bunch of possible reasons conversation size might be limited or
optimal at certain numbers. They choose to focus on mentalizing -- your
ability to maintain a mental model of another person. (I don't know if they
have a strong claim for _why_ they chose this.) One interesting observation
that HN will love is that mentalizing is recursive. When I have a mental model
of your mind, that model includes why I think your mental model of _me_ is,
and so on. If I say something to Fred while George and Harry listen in, I can
reason about what Fred will think of what I say, what George will think of
what Fred will think of what I say, and what Harry will think of what George
will think of what I will think of what Harry will think of... ad infinitum.

By focusing on mentalizing, what matters more is the _pairs_ of people in a
conversation more than the number of people. It's about the relation between
one person and their reaction to another. Pairs grow faster than linear as the
number of participants increases. There are "n(n-1)/2" pairs in a conversation
with "n" people.

Then they make a distinction between "inclusive" and "exclusive" pairs. An
inclusive pair is one that includes you. So in a three-person conversation,
there are three pairs: you-A, you-B, A-B. So two of those pairs are inclusive.

The number of pairs increases quadratically. The number of inclusive pairs
increases linearly. At larger group sizes, most pairs of people don't include
you.

They claim four is the magic number because that's the largest conversation
size before the exclusive pairs outnumber the inclusive ones. With four
people, there are three inclusive and four exclusive pairs. With five people,
there are four inclusive and six exclusive.

It's a neat observation, but they note themselves that they are basically
doing a post-hoc analysis. They started with four and then tried to find some
math that makes it special, and eventually found two lines that cross at that
point.

I do think there might be something to it. If you assume that the most
valuable interactions are ones that involve you (versus deriving value from
seeing what two people say to each other), then it stands to reason that you
want to avoid conversations where most utterances aren't from you or to you.

But that also presumes (1) people don't derive much value from watching others
talk to each other and (2) all participants are communicating to each other
equally. Neither of those is true in practice.

I think a smarter way to look at it is that people strive to maximize the
total value they get from all pair-wise communications. One way to do that is
in a small even-handed conversation. But you can also get that by:

1\. Giving a speech where you get to do almost all of the utterances. So even
though there are many many pairs, most of those channels are silent, and most
of the communication does involve you.

2\. Watching a debate where even though your aren't participating, you get a
lot of value from what the other two are saying to each other.

3\. Less formal approximations of the above. All of us have probably
experienced a conversation that grew to larger than four people because a
minority of them had more dominant personalities so you end up with a couple
of "performers" and some "audience" though people occasionally change sides.

Anyway, fun paper.

~~~
kragormonkey
Paper seems paywalled. How are you reading this? Any mirror?

~~~
ItsMe000001
Did you try Sci-Hub? Always try Sci-Hub.

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linkmotif
The Discord engineering blog post this week has a fascinating sentence on this
topic, perhaps much more interesting to me than the engineering itself:

> Every audio/video communication in Discord is multiparty. Supporting large
> group channels (we have seen 1000 people taking turns speaking)

[https://blog.discordapp.com/how-discord-handles-two-and-
half...](https://blog.discordapp.com/how-discord-handles-two-and-half-million-
concurrent-voice-users-using-webrtc-ce01c3187429)

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anotheryou
More than 4-5 people simply gets impractical, but that's not such a big deal.
With some restrictions you can have meetings with more people and e.g. at a
long table it's simply a balance of distance (for voice and non verbal clues)
and frustration of not being able to talk (at some point you just tell it your
neighbor, splitting the group when it gets too big).

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DoreenMichele
We have the terms monologue and dialogue, but I'm not aware of words for 3
speakers or more specified by number. (They may exist, but presumably aren't
in common usage.)

So I'm a little surprised to learn that four-way conversations are a thing,
actually. Or an important thing, I guess. Not that they exist per se, but that
they are an important demarcation.

~~~
jplayer01
Four way conversations are only relevant as a concept in this case because of
the effects on what would be considered a discussion at that number (or more)
of participants.

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amelius
Not on the internet ...

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platz
> we present one novel possible explanation for the four-person conversation
> size constraint.

But we're not going to tell you in the abstract.

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alexpetralia
This is really not rocket science - is a mathematical model required, and even
reflective, of reality here?

~~~
ozzmotik
id suggest that there is no inherent need for mathematical models at all,
unless there was a specific desire in the first place to produce said models
for some reason. while certainly one would hope that formal models and
analysis is performed in the pursuit of some noble/practical end, sometimes
it's just fun to research things for the sake of it, because there's always
the possibility that in researching one concept, you get exposed to an
expanding universe of other concepts that depend on that original one which
you never would have considered without the context of the research being
performed.

that being said, i think having a formalized way of speaking about the limits
of social discourse could be highly beneficial in several different contexts,
such as providing effective group therapy, the representation of social
interaction in film/literature/etc, and beyond that it can also be used to
reason better about the nature of that squishy device that evolved to the
point of being able to even comprehend the idea of "conversations" in general,
no less the concept of having multiple of them simultaneously

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buboard
that means webRTC can be quite useful

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carapace
The dynamics of a good conversation are almost identical to those of a good
game of hacky-sack.

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abraham_lincoln
6 ways from the Mythical Man Month, right?

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sjg007
Have you ever played the game telephone?

~~~
anonytrary
[https://cdn.shopify.com/s/files/1/0535/3509/products/buy_sel...](https://cdn.shopify.com/s/files/1/0535/3509/products/buy_sell_1024x1024.jpg?v=1426516607)

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vignesh_m
Behind a paywall :/

