Effects of temporal placement of response prevention on extinction of avoidance in rats

Two experiments investigated the effects of prior extinction trials upon the effectiveness of response prevention procedures (flooding) in facilitating extinction of avoidance in rats. The results showed that both prior CS only extinction trials and response prevention independently hastened extinction and that response prevention is enhanced if prior extinction has already taken place. The results were interpreted as being consistent with a relaxation interpretation of extinction of avoidance behavior providing a ‘distraction’ or ‘attention shift’ factor is incorporated into theory.     

The effect of a conditioned fear inhibitor (CS-) during response prevention upon extinction of an avoidance response

Pairing a Pavlovian safety signal (CS—) with a response prevention period was contrasted with other response prevention procedures to determine relative effectiveness for the elimination of learned avoidance behavior. After acquiring a one-way avoidance response, five groups of ten rats received various blocking or control treatments and were then compared on extinction performance. The four blocking treatments included blocking paired with a safety signal; blocking only; blocking paired with a novel stimulus; and blocking paired with a preexposed noncontingent tone. The fifth group served as a handling control. Compared to the handling control, all four blocking groups reached extinction criterion in fewer trials. Further, the safety signal group extinguished faster than the blocking only group or the blocking with noncontingent tone group. Results were viewed as an indication of the potential efficacy of pairing-conditioned fear-inhibiting cues with response prevention procedures for the elimination of fear-motivated behavior. Implications for behavioral therapy techniques were discussed.     

Effects of progesterone and nesting materials on response prevention and extinction of avoidance in rats

Female rats received either progesterone or saline injections prior to learning a simple one-way avoidance response. During a 10-min response prevention procedure half of the animals in each group had nesting material present while the remaining rats did not. The availability of nesting material during response prevention hastened extinction while progesterone injections significantly increased the frequency of nesting activities during response prevention but did not affect rate of extinction. The availability of nesting materials increased the frequency of standing but reduced the frequency of crouching. The results were discussed in terms of the role of ethological displacement activities during response prevention as well as the role of ‘relaxational’ activities as discussed by Baum and Denny.     

The effects of single-component extinction of a three-component serial CS on resistance to extinction of the conditioned avoidance response

Central to a fear interpretation of how avoidance responses are maintained in the absence of further CS-UCS pairings is the underlying assumption of an existing gradient of fear across the CS-UCS interval. Extrapolations based on this gradient lead to a number of differential predictions concerning the topography of avoidance responding during extinction. The present research was concerned with the differential effects of extinguishing separate components of the CS complex upon responding to the complete CS complex during extinction. In Phase 1 of the study, rats were classically conditioned to a three-component serial CS (S₁/S₂/S₃) followed by shock. Each subject was then given avoidance training in a one-way apparatus to a criterion of one successful avoidance. In Phase 2, subjects were divided into four groups, with three of the groups receiving nonreinforced exposure for 25 trials to one of the components of the serial CS (S₁, S₂, or S₃). The fourth group (S₀) was exposed for the same period of time to the apparatus cues. In Phase 3, the total stimulus complex was reintroduced in its original order, and animals were tested until extinction of the instrumental response was reached. The results are consistent with the hypothesis that a fear gradient exists in extinction and decreases in magnitude as the distance from the point of UCS onset increases.     

Using extinction to promote response variability in toy play

We report the effects of extinction and positive reinforcement on the number of untrained topographies emitted by children with toys. Baseline showed no appropriate toy play. Participants were then trained individually on one topography for each toy. Previously reinforced topographies of toy play were placed on extinction, resulting in the induction of untrained topographies.     

The effect of response force on avoidance rate

In a Sidman-avoidance schedule of counter losses for two human subjects, the loss-to-loss and response-to-loss intervals were 20 sec. The avoidance response was a vocal response that was louder than a minimum vocal requirement. This requirement was set at 80 db, 95 db, or 110 db. In addition to vocal responses meeting the minimum requirement, all responses exceeding a threshold of 75 db or louder were recorded. The rate of both above-threshold and avoidance responses decreased as the response-force requirement increased. Thus, high response-force requirements produced an effect on avoidance responding similar to its effect on positively reinforced responding.     

ACTH produces long-lasting recovery following partial extinction of an active avoidance response

Recent data suggest that ACTH administration produces recovery of an extinguished passive avoidance response at an unusually long injection-to-test interval. The present experiment sought to explore further the durability of recovery by examining the effect of ACTH following extinction of one-way active avoidance. Adult rats were injected with 16 IU ACTH, an equivalent volume of the ACTH vehicle gel, or saline 48 h after a previously learned active avoidance response was partially extinguished. Different groups from each treatment condition were tested 15 min, 24 h, or 7 days after injection. ACTH improved avoidance performance at all injection-to-test intervals relative to saline and vehicle gel injected controls. These data indicate that unlike reversal of other types of performance decrements, in which the effect of ACTH appears to be transient, administration of the hormone following an extinction treatment can produce enduring improvement of avoidance performance.     

Backchaining of relaxation in the extinction of avoidance

After rats were trained in one-way avoidance, two types of nonshock treatment were given to assess the degree to which fear of the shock area is affected by (a) nonshock responding (regular extinction trials) apart from (b) repeated exposure to the shock area in the absence of shock (response prevention). Different groups of regular extinction rats received 1 or 27 trials; response prevention control rats were equated with regular extinction rats on amount of nonshock exposure to the shock area and other variables. Fear of the shock area was measured on a posttreatment passive avoidance test. Regular extinction trials led to less fear of the shock side than response prevention trials when 27 nonshock trials were given. The results (a) suggest that relaxation back-chains from the safe to the shock area over repeated avoidance extinction trials, and (b) clarify existing problems of maintained fear with the response prevention technique.