bit.listse "Abbott,

CSGnet Archive CSG1994
1

[From Sam(uel) Saunders (941026:2100 EDT)]

Bruce Abbot (941026:1250 EST) makes several points I woth commenting upon.
I too had taken mild offense at Bill Powers' (941025:1235 MDT) comments on
lack of attention to detail in EAB research. In addition to Bruce's
comments, I would also point out that most EAB researchers attempt to keep
essentially "standard conditions" for variables not under explicit study.

I also had been about to respond on the question of 80 % FFW deprevation.
As I recall, Bill Stebbins presented data for a number rats which suggested
that 80 % FFW was probably closer to normal body weight than FFW. I also
recall a note (but not the reference, unfortunately) by Malott and some of
his WMU students in which they compared weights of free feeding pigeons
(locally captured and held in the normal colony) to those of pigeons in on
a local street and to those of pigeons at and around a local grain elevator.
Again, 80 % FFW was closer to "normal" weight (in fact, the normal weight
tended to be even lower among town animals in winter). In addition to
abtaining food easily, normal colony animals have little to do other than
eat.

On the experiments, I agree that some deprivation may be necessary to start.
With chinchillas and with chickens, I have had some success with just
dropping suplimentary feeding at the start of the experiment, and making
the apparatus the only source of food. Weight tends to drop for a time, but
as you know it takes several days to drop to dangerous levels, and by that
time animals are frequently responding. As another alternative, in
Psychoacoustic experiments with cats we used a thick fish soup which was
apparantly appealing to the cats, and we were able to train and test
them at 90-95% FFW. What about autoshaping? As I recall, it can be done with
rats, but it is tricky. Does it require retractable bars ? I have used
autoshaping with pigeons, but not with undeprived pigeons. As to water- why
not make that response-contingent as well ? It could make record keeping
easier. You could make it easy (FR1 for a long drink) while looking at food
schedules, but be set up to manipulate the water schedule as well. In
addition to eating in bouts, I suspect you will see circadian variations,
and you should get more activity in the dark than the light part of the day.

Sam
Samuel Spence Saunders, Ph.D.
sssaunders@delphi.com

2

[From Sam(uel) Saunders (941101.1715 EST)]

Bruce Abbot (941031.1500 EST) asks about his view of "TRT". I agree that
his description of reinforcement theory matches my understanding. An
example of a state-change as reinforcer would be from some of the work of
Lattal and others, using a change in the rate of non-contingent food ("VT
schedule") to support key pecking.

One thing that seems to me to be missing in the considerations of both Bill
and Rick, on the one hand, and Bruce, on the other, is the stimulus side of
the "three term contingency". In the E-coli, and in many other situations,
there are both stimulus and "reinforcing" aspects to the same event. An
alternative model might be the following:
   Two 'stimulus contexts':
       A. Increasing gradient
       B. Decreasing gradient
   In A, a 'flip' will be followed by either an equal (increasing gradient)
or worse (decreasing gradient) consequence, and so would be expected to
decrease in probability.
   In B, a 'flip' will be followed by either equal (decreasing gradient) or
better (increasing gradient) consequence, and so should increase in
probability.

I suppose it is incumbent on me to render the above in a working simulation.
It will be a little while before I can get to that. I decided to try a 32
bit OS2 Pascal rather than the patched Turbo 7.0, which only supports 16 bit
OS2 code. The compiler supports Turbo fairly well, but does not include the
graphics library. I am constructing presentation manager graphics to mimic
the graphics you are using, and when I have that working, I should be able
to run Turbo code without hacking, so it will be easier to exchange.

I posted 2 notes on Saturday, but I haven't seen any trace of them, so I
suppose they were lost along the way. I have a backup of one, which I will
repost. The other I will have to re-construct.

Sam
Samuel Spence Saunders, Ph.D.
sssaunders@delphi.com