The influence of shock during response prevention upon resistance to extinction of an avoidance response

Abstract

A recent study found that avoidance extinction is equally facilitated by response prevention (blocking) whether the latter involves CS-alone or CS-shock presentations. An experiment was performed to determine whether this result was due to the use of a lengthy shock (5 sec) during response prevention. Five groups of rats were extinguished: (1) without prior blocking, (2) after blocking with CS only, (3) after blocking with a lengthy (5 sec) CS-contingent shock, (4) after blocking with a brief (.5 sec) CS-contingent shock, or (5) after blocking with a brief (.5 sec) shock only. The group blocked with the brief CS-contingent shock was substantially more resistant to extinction than the other four groups. The unblocked group and the group blocked with brief shock only required more trials to extinguish than the groups blocked with CS only or with lengthy CS-contingent shock, but did not differ from each other. The groups blocked with CS only or with lengthy CS-contingent shock also failed to differ from one another. The data support a significant role for Pavlovian conditioning processes in the effect of response prevention upon avoidance extinction.

The role of fear in theories of avoidance learning, flooding, and extinction.

“…These low activity levels could indicate that freezing has become the "competing response." The Marrazo et al (1974) and Bersh and Miller (1975) experiments discussed previously certainly indicate that competing responses learned during flooding can mediate the extinction of avoidance responding. No experiment has conclusively demonstrated, however, that competing responses either do mediate extinction or are necessary for such extinction.…”

“…There are, however, two problems with this interpretation. First, Bersh and Miller (1975) showed that Marrazo et al's results were due to their use of long (S-sec) shocks during flooding. These long shocks seemed to result in jumping and rearing behavior being conditioned to the situation, which in turn facilitated extinction by serving as incompatible responses.…”

The effect of number and minimum duration of post-response-prevention escapes on the resistance to extinction of an avoidance response

“…(2) Shock escape provides negative reinforcement for the response. When escape was unrestricted, the combination of these two factors increased extinction responding for CS-only animals to the level (i.e., 25-35 responses) consistently obtained for control rats (i.e., not exposed to response prevention) in our laboratory (e.g., Bersh & Miller, 1975;Bersh et aI., 1982), but not to the level of the CS-US animals. On the other hand, even 10 unrestricted escapes had no further reliable incremental effect on extinction responding for CS-US animals.…”