[From Rick Marken (950620.1030) --
I think it is significant that reinforcement theorists must develop a new
version of their theory each time a new behavioral situation is described.
For example, in a simple operant conditioning experiment, the occurance of
food following a bar press is considered a reinforcement. I have never heard
reinforcement described as the change from "no food" to "food". So, when I
developed the E. coli demo it seemed reasonable to assume that the direction
of movement following a press was the reinforcement; like the food in the
basic operant conditioning experiment, direction of movement is a direct
result of a response. But, in order to make the reinforcement model of E.
coli behavior work, it was necessary to redefine reinforcement as _change_ in
the direction of movement after a press; change toward the target was the
reinforcement.
It is also sometimes necessary to change what was considered a non-reinforcer
or punisher in certain experiments. This is what happened in the first
version of my R. coli demo. In that demo, a press leading to a change from
non-target to target is considered a reinforcer but a change from one non-
target to another could not be considered a punishment because, if it were,
the reinforcement model wouldn't work.
The events that are considered reinforcement, punishments, etc must be
changed to account for behaviors in different situations because the behavior
of the reinforcement model is determined by the situation. The model will
only work (account for the actual behavior observed) if the modeller can pick
out aspects of the environment that will produce the right behavior. This, of
course, means that the reinforcement model cannot fail as long as one can
find appropriate environmental inputs (appropriate consequences of
responding) for the model.
Martin Taylor (950620 11:10) has noticed this characteristic of reinforcement
theory. He asks:
wouldn't maintenance of the direction of the cursor away from the target be
negative reinforcement, and maintenance of its direction toward the target
be positive reinforcement?
(I presume Martin is referring to the _occurance_ (not maintanance) of a
particular direction of cursor movement). I understand Martin's puzzlement.
But I have gotten used to the idea that reinforcement theorists identify
events as reinforcers, punishers, etc. as necessary to produce the intended
results. The direction of movement of the cursor after a press is considered
a positive or negative reinforcer, a punishment or a non-reinforcer depending
Your original E. coli demo may not have done what you wanted it to do, but
I think your approach was a good one--finding the simplest example of
goal-oriented behavior that could not be accounted for by reinforcement
theory.
I can now see that there is probably no way to show that goal-oriented
behavior cannot be accounted for by reinforcement theory. As long as you can
come up with some aspect of the environment that covaries along with the
behavior being produced you can let that aspect of the environment increase
of decrease the probability of response, as necessary, to get the result you
want.
This is the "power of reinforcement theory" to which Bill Powers
(950617.IHateToSay) described. But I think reinforcement theory only has this
power (to account for any behavior) as long as behavior is delt with in terms
of probabilities of response. Obviously, reinforcement theory could not
account for the quantitative details of the typical compensatory tracking
experiment.
Of course, the power of reinforcement theory exposes its basic flaw. The
power of reinforcement theory is achieved by looking for aspects of the
environment that can account for the behavior we see. But this means that the
same aspect of the environment must be treated as a reinforcer in some
circumstances and a non-reinforcer or punisher in others. Since the theory
provide no independent means of measuring the reinforcingness or
punishingness of the environment, we are free to ascribe these changing
characteritics to the environemnt as necessary to explain behavior. This
is not science; it is tautology.
Best
Rick
···
on whether considering it so contributes to the appropriate behavior of the model. So, in answer to Gary Cziko (950614.1920 GMT) who said:
