Posted by
Hugh Trenchard on
URL: http://friam.383.s1.nabble.com/Meeting-at-St-John-s-tomorrow-tp523290p523339.html
Thanks. The only complex group dynamic I can claim any special knowledge of
is a bicycle peloton, and if I apply the "dropping in" effect and the
"shaking out" effect, I recognize that a bicycle peloton is both a
socialized phenomena and a purely self-organized one. It is also a good
example of a dynamic that is both leader-driven and self-organized.
An example of "dropping in" occurs when a lone rider sees a peloton of
riders ahead, speeds up to catch the group because he knows for a fact that
he will save energy by riding with the group. That's a socialized response,
because he has learned or been taught that there is energy savings in a
group through drafting.
Once he is part of the group, the main physical parameters are energy
savings by drafting and collision avoidance. Both of these result in
continuous positional adjustments within the peloton. A combined
physical/social pattern to result is positional rotation within the
peloton - physical because riders at the front sometimes become so fatigued
that fresh riders behind simply ride past the fatiguing riders, who can then
drop into drafting positions to recover; socialized because riders are also
taught to trade positions.
If we think of the source of the emergent patterns as a ratio of physical to
social behaviour, then as riders at the front of the peloton approach their
phsysiological thresholds, the ratio of physical/social increases. That is,
their fatigue is likely to force a reduction in output so they can recover,
while fresher riders behind maintain speed and pass the fatiguing riders.
In other words, any speed or power output increases that intitially led to
these physiological thresholds may have been leader induced, but once
cyclists approach thresholds, then the pure limits of physiology and physics
take over.
There are many nuances to this analysis of pelotons, but before I get too
profuse here, my main point is that your suggestion of a "dropping in" and
"shaking out analysis" is very helpful, and I agree there is a lot to be
learned from it.
By the way - in addition to this discussion, were there any comments on my
second main observation in Mexico - the "cab sifting" effect in traffic?
Hugh Trenchard
----- Original Message -----
From: "Phil Henshaw" <
[hidden email]>
To: "'The Friday Morning Applied Complexity Coffee Group'"
<friam at redfish.com>
Sent: Wednesday, January 10, 2007 3:50 AM
Subject: Re: [FRIAM] frigatebirds - short video
Oh yes! It's an important reservation that "they could very well not be
aware of the global pattern they are forming, just as in a much larger
flock, birds will [may] only be aware of their immediate neighbours."
In evo. bio. the phrase is that "A is random with respect to B". It is
quite common for things produced by one mechanism are instrumental to
another mechanism which develops quite independently. Most natural
systems develop from 'found objects', as it were.
Now it's possible in a case like this that the social behavior which
makes a bird discover the energy saving groove of 'V' formation flight
is partly evolved and recorded in their DNA. Relying on that, though,
is like throwing darts at a black hole in my way of thinking, your dart
just disappears because it only identifies an assumption. I don't see
how in this case, but sometimes you can identify a larger property, like
if you saw birds 'dropping in' on a forming 'V' rather than 'shaking
out' into the 'V' form. Watching the details of how things happen is
often very helpful.
Phil Henshaw ????.?? ? `?.????
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
680 Ft. Washington Ave
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> -----Original Message-----
> From: friam-bounces at redfish.com
> [mailto:friam-bounces at redfish.com] On Behalf Of Hugh Trenchard
> Sent: Wednesday, January 10, 2007 2:04 AM
> To: The Friday Morning Applied Complexity Coffee Group
> Subject: Re: [FRIAM] frigatebirds - short video
>
>
>
> Phil,
>
> Thanks for the follow up. As Dr. Lissaman says in a
> subsequent post, that
> clip by itself may say nothing, but it's only an indication
> of the type of
> formations I was referring to, namely a complete vee
> formation without
> flapping that I observed (while gliding, and in relatively stationery
> positions - ie. not moving across the sky at high speed), but
> not shown in
> that short video. The "phase change" I referred to would
> have involved
> several frigate birds in the formation like the two shown
> next to each other
> in the video.
>
> By the way, I would say that there may be forms of coupling
> that go on when
> two lions on the savannah walk side-by-side. For example
> their gaits may be
> synchronized or phase-locked. It would be interesting to see
> what emergent
> patterns might arise if you put one hundred globally coupled in that
> fashion, side-by-side and set them all walking.
>
> My thought on the leadership question is that the
> frigatebirds wouldn't
> undergo a "phase change" unless there was some energy
> reduction benefit for
> them to do so. This would be an evolutionary development and
> in my mind
> would apply across species. But as you or someone pointed
> out, there are
> ways to confirm that, as I certainly can't state that as a
> fact. There may
> be elements of leadership involved, but in my mind any
> emergent formations
> are more likely to result from local physical rules, although
> I can imagine
> some emergent patterns could arise from a combination of
> leadership and
> local physical rules, and there probably are plenty of
> examples of that.
>
> In terms of "physically feeling the vee formation effect", I
> would argue
> that they can certainly feel the reduction in energy output
> required in the
> most efficient positions, and perhaps are aware of the
> positions of other
> birds in their field of view and perhaps have seen other Vees
> off in the
> distance, but they end up in their formations because they learned,
> originally by accident at some stage in their evolutionary
> development, that
> there was smaller energy output in certain positions. My
> point is they
> could very well not be aware of the global pattern they are
> forming, just as
> in a much larger flock, birds will only be aware of their immediate
> neighbours.
>
> >From my experience as a bicycle racer, it's obvious that
> cyclists can
> >feel
> the physiological benefits of certain formations, but in a
> large peloton,
> the cyclists may easily not be aware of certain pattern
> formations, which
> become observable only from the air and upon a closer
> analysis of their
> global movements.
>
> I agree that we are largely guessing when determining the underlying
> mechanisms for certain behaviours, but if we can find similar
> behaviours
> among different groups, and can identify mechanisms
> underlying one group,
> then it is some evidence similar mechanisms apply to the
> other groups. Not
> proof obviously, but it is *some* evidence, and it is
> certainly cause for
> closer investigation for the curious minded.
>
>
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