You can get a similar effect by delivering occasional random shocks to a
rat who has a history of leverpressing to avoid shock in an operant
conditioning chamber.
Leverpressing will be maintained steadily almost indefinitely (I've seen it
continue for several hours).
The usual explanation in the behavioral community is that the shock has
also become a discriminative stimulus (cue) for behaviors which in the past
have been effective in excaping from or avoiding shock.
Hence, when shocked, the rat does what in the past has been effective.
Since the random shocks are delivered only occasionally, the contingency is
very difficult to discriminate from one where the response actually is
effective in postponing shock.
This is sometimes called 'superstitious avoidance behavior'.
The analogs in human behavior should be obvious.
At 11:32 AM -0600 10/31/00, Mike Scoles wrote:
>To answer Stephen's question, I think you would need at least one more group:
>
> Group 3: PRF --> EXT --> EXT
>
>And, according to Stephen, the measure of trials or time to an extinction
>criterion would begin at the end of the first phase in each case.
>
>BTW, something about Stephen's original post made me think that the partial
>reinforcement extinction effect, or at least explanations for it, mirrors an
>effect seen in aversive learning. "Vicious circle" behavior can be seen
>during
>extinction of an escape response. The standard procedure involves a long
>runway
>with an electrified floor. (The shock does not have to be intense.) It works
>best if the rats "dropped" into the start box using a trap-door
>arrangement. The
>rats must run to the other end of the runway to escape the shock. The escape
>response will extinguish fairly rapidly if shock is turned off in the entire
>runway, but will persist indefinitely if just the middle portion of the runway
>remains electrified. That is, the rats will actually run some distance
>without
>being shocked, cross the electrified portion, and then continue running to the
>safe box.
>
>The usual explanation is similar to Amsel's explanation of PREE.
>Supposedly, the
>frustration encountered during extinction is similar to the frustration
>encountered during partial reinforcement, so the response persists under these
>similar cues. In vicious circle, the explanation that is frequently given
>is that
>the discomfort/anxiety experienced during "punished" extinction is similar
>to the
>discomfort/anxiety experienced during acquisition of the escape response,
>so the
>response persists under these similar cues.
* PAUL K. BRANDON [EMAIL PROTECTED] *
* Psychology Dept Minnesota State University, Mankato *
* 23 Armstrong Hall, Mankato, MN 56001 ph 507-389-6217 *
* http://www.mankato.msus.edu/dept/psych/welcome.html *
