Thanks, Scotty

[From Rick Marken (941105.0830)]

Bill Powers (941105.0650 MST) --

What a nice way to wake up; thanks so much Scotty. But I do feel
a little stupid for not noticing the crucial problems with the
code myself. They were a tad subtle; just a change of sign in
two places -- that make ALL the difference -- but I should have

             pTumbleGivenSminus := pTumbleGivenSminus {-}+ LearnRate;

             pTumbleGivenSminus := pTumbleGivenSminus {+}- LearnRate;

You may notice that I have commented out the incorrect comparisons and
signs and entered the correct ones that fit the aliens' theory, in which
the sign of NutSave makes a difference. If you drop this modified
procedure into your program, you will see a random walk. At least I see
one on the ship's computer.

This is nice to know -- since this is exactly what I saw when I ran
similar simulations way back in the mid eighties. When Bruce reported
the aliens' result, I thought that there might have been a change in
the nature of reality over the last 10 years; fortunately, it was just
a change in the sign of a couple of computer commands.

These aliens have slippery ways of getting around holes in their

Tell me about it!

The aliens will discover, some day, that the appearance of reinforcers
as causes of behavior is such an illusion. But they are not ready for
this discovery yet.

Tell me about it!

I think it is only fair to warn Bruce that when he shows the corrected
version of ECOLI4 to the aliens, they are likely to become viscious and
abusive. Be prepared to beam him up, Scotty;-)