On Sat, 03 Nov 2001 11:26:34 -0600 Mike Scoles
<[EMAIL PROTECTED]> wrote:
> Stephen's distinction between a variable ratio and random ratio is one that I
> was not aware of, but then I don't teach operant methods. I wonder if the
> selection of one of these schedules is based on the technology that is used.
> In a lab setting, the "true" variable ratio would be easy to program using a
> film programmer (does anyone still use those?) or one using audio tape. This
> schedule would also be easy to program with a computer, but the random ratio
> would be much easier. Of course, the film/tape programming does not provide
> a random "true" ratio, but one could be programmed with a computer, where the
> sampling of ratios could be done with or without replacement.
This is the procedural distinction between a variable ratio and
a random ratio (and a variable interval vs. random interval).
This procedural difference captures a potentially important
difference between the two schedules.
In the case of the VR, the experimenter explicitly controls the
distribution of ratios when the holes are punched into the tape.
In the case of the RR, the distribution/sequence is left up to
the pseudorandom-number generator when the experimenter does a
call to some RND() subroutine. Experimenters need to understand
how their RND() routine works in order to have a reasonable guess
as to the actual sequence that occurs in the box.
Knowledge of the sequence is important because of the basic mode
of operation of the ratio schedule. Ratio schedules depend on
work rate alone. The subject must respond to obtain a
reinforcer. If you respond faster, the more quickly are
reinforcers obtained. If you respond slower, then the more
slowly are reinforcers obtained. If you stop responding then
nothing will change the response requirement to the next
reinforcer. Variations in the sequence can cause
disruptions of response rate which can cascade into causing
the subject to stop responding ("ratio strain"). This can turn
in extinction, functionally.
Now I found this a fascinating issue, but not many other people
did.
Ken
(Who used "the golden tape" sequence of Catania & Reynolds,
1968)
>
> A number of (fascinating?) research questions come to mind. Would subjects
> (or participants) respond differently to:
> a) a fixed sequence of ratios of different lengths
> b) a random sequence of ratios of different lengths
> i. selected with replacement
> ii. selected without replacement
> c) a random ratio schedule, where the probability of reinforcement is
> constant
> d) how would the results under (a) and (b) be affected by the number and
> range of ratios
>
> I bet the answers to all of these questions are available in forgotten issues
> of JEAB.
>
> Stephen Black wrote:
>
> > . . . if it was programmed on VR, then if one produces many
> > responses without payout, the probability of a payout must rise
> > (i.e. you must be getting to the end of a long ratio). So if one
> > player gives up, it means that the next player would have a
> > better chance. Because of this, on reflection, I doubt that this
> > is how it's done.
> >
> > There's another schedule, called a random ratio, which seems more
> > likely. This reinforces each response with a preset probability
> > of winning.
>
> --
> *****************************************************************
> * Mike Scoles * [EMAIL PROTECTED] *
> * Department of Psychology * voice: (501) 450-5418 *
> * University of Central Arkansas * fax: (501) 450-5424 *
> * Conway, AR 72035-0001 * *
> ********* http://www.coe.uca.edu/psych/scoles/index.html ********
----------------------
Kenneth M. Steele, Ph.D. [EMAIL PROTECTED]
Dept. of Psychology
Appalachian State University
Boone, NC 28608
USA
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