Beaver Control

[From Rick Marken (930817.0930)

Boy, what a quiet net. Guess everything's solved, eh?

I can't believe that no one picked up on this wonderful post from
Avery Andrews (930815.2100) --

A beaver will cast about quite frantically for something--anything--to
stop the sound of running water, and in one experiment a beaver found

>its relief by plastering mud all over the loudspeaker from which the

recorded gurglings emerged!

cited from Wilsson, 1974, Observations and Experiments on the Ethology
of the European Beaver, Viltrevy, Swedish Wildlife 8, pp. 115-266.

This is a great example of perceptual control. I think anyone could
understand the implications. The sound is not a "stimulus" for "dam
building behavior" because the beaver will clearly do "anything" to
stop the sound; any behavior that produces the intended result will
apparently do. The beaver is clearly controlling a perception (of
sound) but we see this behavior as "dam building" when the beaver
is controlling this perception in it's natural environment. In an different
sort of environment, with a different feedback function relating the
beaver's outputs to its perception of sound, the same process of
perceptual control looks like "plastering mud on a loudspeaker". Beaver's
that live in the "loudspeaker and mud" environment would be described
as "speaker plasterers" rather than dam builders. This is the ecological
version of the "behavioral illusion" -- the "ecological illusion"?

What a GREAT example, Avery. The Wilsson article should definitely go
into the stack of conventional life science studies of perceptual control.

(The context shows no evidence of Dennett understanding hierarchical
control systems, but the reference seems worth tracking down...)

You bet it's worth tracking down. And all Dennett would have to understand
is that behavior is the control of perception (the hierarchical stuff can wait
for the advanced course) to see the true interest of this demonstration. I
wonder why Dennett brought up this beaver study? To show that Beaver's
build dam's consciously? unconsciously? Another great case of a life
not noticing what is going on before his very eyes -- perceptual control.