To continue the discussion of moths & S-R systems, what would be
the story about a dog that was hardwired to salivate when it
smelled food? Abstractly, these two systems look alike w.r.t.
what is inside the organism:
_______ _______
--->| det- | Y/N | eff- | --->
--->| ect- |-------> | ect- | --->
--->| or | | or | --->
------ ------
e.g. a vector of sensory inputs gets transduced to an approximately
ON/OFF signal, the ON value of which sets off an effector. The difference
is that in the moth case, the presumed result of the effector is to
make the sonar signal go away, while in the salivation case, the effector
does NOT make the smell of food go away. But as far as what's inside
the critter itself, the setups look pretty much the same.
And furthermore, is it so obvious that the moth's system is actually
making the signal go away? What it might be doing is making the moth
undetectable by getting it on the ground as fast as possible (I don't
know whether the dropping actually normally gets the moth out of sonar
range or not).
So it seems to me that exactly the same hunk of circuitry might be
appropriately regarded as an ECS or an S-R system, depending on
whether there is an R-S connection that is an important aspect of
the functioning of the system. E.g. if the dropping systems serves
get the moth out of sonar range fast, it's an CS, if it gets it
to be undetectable against the ground, though still in range, it's
S-R.
Avery.Andrews@anu.edu.au