[from Gary Cziko 931102.2212 GMT]
Bill Powers (931101.1010 MST) responding to Gavan Lintern (931101.0836)
2. There is some benefit to the individuals in acting in a way
that creates these patterns, a benefit due indirectly to the
pattern itself.
The second choice might be illustrated by the V-patterns in which
geese fly. While no goose has a control system for producing a V,
it is a fact of aerodynamics that the effort of flying is least
for a goose flying just behind and to the side of another goose.
Assuming that geese will fly so as to avoid excessive effort,
each goose could learn that flying in a certain position relative
to another goose will reduce the effort to an acceptable level.
The lead goose gets fatigued first, and so drops back after a
while to the less effortful position. This creates the impression
that the geese are deliberately taking turns at being the leader,
but a sufficient explanation is simply that the lead goose gets
tired.
That the V-pattern itself is not controlled would be indicated by
variations in the V-pattern as a function of wind direction.
This summer I started doing some serious bicyling, going on training rides
with local racers. We form what are called pacelines, with all riders in
one or two columns, each rider's front wheel as close as 6 inches from the
back wheel of the rider in front. This "drafting" allows much higher
speeds than is possible when riding alone. The front rider "pulls" for as
long as he or she can maintain the pace and then swings off and gets on the
back of the paceline where he or she "sits on."
When the wind is coming from straight ahead or from behind, straight
pacelines are formed. But when there is a strong crosswind from the right
(for example), the pacelines are slanted with each rider riding behind and
to the left of the rider in front. These slanted pacelines are called
echelons from the French word meaning "slanted pacelines used by bicyclists
cycling in crosswinds in order to control for least amount of effort while
riding fast" (French is SO elegant).
So the configuration of the paceline VARIES according to the wind direction
and is not controlled. Rather, what is controlled is the perception of
least work while pedalling.
I have often noticed that the geese around here do not fly in perfect V's.
Often one leg of the V is straighter back than the other. If they are
controlling for least effort while flying, then the straighter back leg
should be on the side facing the wind. I will have to check if this is the
case the next time they pass overhead to see if they are as smart as we
bicyclists.--Gary
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Gary A. Cziko Telephone: 217-333-8527
Educational Psychology FAX: 217-244-7620
University of Illinois E-mail: g-cziko@uiuc.edu
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Champaign, Illinois 61820-6990
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