Theoretical implications of the neurotic paradox as a problem in behavior theory: An experimental resolution

Preextinction Stress Prevents Context-Related Renewal of Fear

Extinction learning, which creates new safety associations, is thought to be the mechanism underlying exposure therapy, commonly used for the treatment of anxiety disorders and posttraumatic stress disorder. The relative strength and availability for retrieval of both the fear and safety memories determine the response in a given situation. While the fear memory is often context-independent and may easily generalize, extinction memory is highly context-specific. "Renewal" of the extinguished fear memory might thus occur following a shift in context. The aim of the current work was to create an enhanced and generalized extinction memory to a discrete stimulus using stress exposure before extinction learning, thereby preventing renewal. In our contextual fear conditioning paradigm, 40 healthy men acquired (Day 1), retrieved and extinguished (Day 2) the fear memories, with no differences between the stress and the control group. A significant difference between the groups emerged in the renewal test (Day 3). A renewal effect was seen in the control group (N = 20), confirming the context-dependency of the extinction memory. In contrast, the stress group (N = 20) showed no renewal effect. Fear reduction was generalized to the acquisition context as well, suggesting that stress rendered the extinction memory more context-independent. These results are in line with previous studies that showed contextualization disruption as a result of pre-learning stress, mediated by the rapid effects of glucocorticoids on the hippocampus. Our findings support research investigating the use of glucocorticoids or stress induction in exposure therapy and suggest the right timing of administration in order to optimize their effects.

The Power of Extrapolating Basic Laboratory Principles: The Behavioural-Cognitive Approach of Implosive Therapy

The purpose of this article is to emphasise the importance of basic research in the advancement of theory and clinical technique. To illustrate the power of such a strategy the theory and imagery technique of Implosive (Flooding) Therapy will be briefly described along with a recent modification that has resulted in the development of a new technique which is capable of reactivating all past traumatic memories responsible for the development and maintenance of psychopathology. This new approach has resulted in a number of important discoveries that challenge many currently held beliefs.

A discriminated conditioned punishment model of phobia

Traditionally, the signaled avoidance (SA) paradigm has been used in an attempt to better understand human phobia. Animal models of this type have been criticized for ineffectively representing phobia. The SA model characterizes phobia as an avoidance behavior by presenting environmental cues, which act as warning signals to an aversive stimulus (ie, shock). Discriminated conditioned punishment (DCP) is an alternative paradigm that characterizes phobia as a choice behavior in which fear serves to punish an otherwise adaptive behavior. The present study quantifies the differences between the paradigms and suggests that DCP offers an alternative paradigm for phobia. Rats trained on either SA or DCP were compared on a number of behavioral variables relevant to human phobia. Results indicate that rats in the DCP paradigm responded significantly earlier to warning signals and were more effective at preventing shocks than rats in the SA paradigm. Implications of this alternative paradigm are discussed.

The S-S construct of expectancy versus the S-R construct of fear: which motivates the acquisition of avoidance behavior?

The authors provided a differential test between stimulus-stimulus (S-S) and stimulus-response (S-R) theory predictions in regard to the roles that the constructs of expectancy and of fear play in maintaining classically conditioned fear responding within the context of a human conditioned-avoidance paradigm. After the participants had developed sustained avoidance responding, their shock electrodes and avoidance response apparatus were removed to enhance the cognitive expectancy that the conditioned stimulus (CS) would not be followed by the unconditioned stimulus (UCS). This manipulation of expectancy was successful in 96% of the participants. The study was conducted over a 2-day period and involved 1 experimental group and 3 control groups. During the test trials, the authors used autonomic and self-report indices of fear to assess the presence or absence of fear to the CS. The data disconfirmed the prediction of the S-S theory that fear to the CS would be extinguished. The authors discuss the implications of this finding for S-S theories and for approaches in cognitive behavior therapy.

Two-factor theory has strong empirical evidence of validity

Traditional two-factor theory is supported by parallels in the clinical literature. Theoretical problems with two-factor theory are obviated by the role of safety signals, which serve as positive conditioned reinforcers and retard the extinction of conditioned fear.

Explaining avoidance: two factors are still better than one

Two-factor theory remains a viable account of avoidance behavior. By emphasizing the interplay of respondent and operant contingencies, two-factor theory encourages the analysis of stimuli that mediate molar consequences and incorporates control by local events as well as events that are temporally remote, improbable, or cumulative.

Extinction of responding maintained by timeout from avoidance

The resistance to extinction of lever pressing maintained by timeout from avoidance was examined. Rats were trained under a concurrent schedule in which responses on one lever postponed shock on a free-operant avoidance (Sidman) schedule (response-shock interval = 30 s) and responses on another lever produced 2 min of signaled timeout from avoidance on a variable-ratio 15 schedule. Following extended training (106 to 363 2-hr sessions), two experiments were conducted. In Experiment 1 two different methods of extinction were compared. In one session, all shocks were omitted, and there was some weakening of avoidance but little change in timeout responding. In another session, responding on the timeout lever was ineffective, and under these conditions timeout responding showed rapid extinction. The within-session patterns produced by extinction manipulations were different than the effects of drugs such as morphine, which also reduces timeout responding. In Experiment 2 shock was omitted for many consecutive sessions. Response rates on the avoidance lever declined relatively rapidly, with noticeable reductions within 5 to 10 sessions. Extinction of the timeout lever response was much slower than extinction of avoidance in all 4 rats, and 2 rats continued responding at baseline levels for more than 20 extinction sessions. These results show that lever pressing maintained by negative reinforcement can be highly resistant to extinction. The persistence of responding on the timeout lever after avoidance extinction is not readily explained by current theories.

An information-processing perspective on childhood anxiety

In the past decade, cognitive theories of adult anxiety disorders have become increasingly complex, reflecting enhanced understanding of anxiety-related information-processing. This growth has fostered the development and enhancement of numerous assessment and treatment methods. Unfortunately, similar growth has been slower to occur in theories of childhood anxiety. This paper attempts to foster such growth by adopting an information-processing perspective. Doing so expands the extant cognitive perspective on childhood anxiety in four major ways. First, the division of cognitive processing into a sequence of steps provides a framework for organizing predictions regarding cognitive factors in childhood anxiety. Second, consideration of the cognitive operations active during each stage in the sequence facilitates elaboration of the types of cognitive deficits and distortions characteristic of anxious children. Third, it promotes development and application of performance-based assessment methodologies. Finally, an information-processing perspective highlights several targets for clinical intervention that may promote widespread change in an anxiety-supporting cognitive system.

Examination of a backchaining/counterconditioning process during the extinction of conditioned fear

Two experiments using rat subjects are reported which attempt to delineate the theoretical mechanisms involved in exposure/extinction procedures that are used to eliminate conditioned fear. In Experiment 1, a within-subjects design was employed to study the temporal course of the extinction process by examining the relationship among three separate measures of classically conditioned fear--suppression of an ongoing, operant behavior during the nonreinforced fear-eliciting CS presentation, the time to the first response during this CS presentation, and the time to recover responding following termination of the CS. The results indicated a temporal relationship among these measures, both within and across nonreinforced CS trials, which were considered to reflect a backchaining of a fear-antagonistic response during extinction, and provided an empirical demonstration of an extinction process consistent with Denny's (Behaviour Therapy and Experimental Psychiatry, 7, 315-321, 1976) elicitation/backchaining explanation of extinction. Experiment 2 attempted to manipulate the course of extinction and the temporal relationship among these three fear measures through the paired presentations of the fear CS with a palatable substance (maltose). This procedure produced greater extinction apparently by facilitating the backchaining process. These results are discussed with implications for exposure-based therapies.

Contributions of animal studies of response prevention (flooding) to human exposure therapy

The behavioral technique of response prevention (flooding, exposure therapy, implosive therapy) is reviewed. Contributions of animal studies of avoidance-extinction to therapy of human phobic disorders are discussed. These include the delineation of the importance of treatment duration and the facilitative effects of distraction during treatment. Animal studies showing certain pharmaceutical and hormonal agents increase treatment efficiency are reviewed, suggesting improvements in human therapy.