The relationship between underpredicted pain and escape

Escape and avoidance that are disproportional to the danger of the pertinent stimulus are important clinical problems that are often related to inaccurate (catastrophic) expectations. One possible source of such expectations is a prior, underestimated aversive experience. In the present experiment the hypotheses that underestimated pain leads to escape and that it leads to avoidance were tested. In order to control for the effect of the intensity of the pain stimulus, a control group that received 20 pain stimuli of high intensity was formed. Subjects in the experimental condition received 17 pain stimuli of low intensity and 3 of (unexpectedly) high intensity (experimentally induced underprediction). Underprediction of the high intensity stimulus was significantly related to escape, but not to avoidance. The results suggest that the way in which avoidance was operationalized accounts for this. The strong support of the hypothesized relationship between underpredicted pain and escape is an important finding, however.     

Psychophysiological responses during analogue systematic desensitization and non-relaxation control procedures

This investigation tested the hypotheses than an analogue systematic desensitization procedure (SD) would be both more effective and more efficient than a comparable non-relaxation control procedure (NRC) with respect to subjective report, behavioral and psychophysiological variables. Phobic subjects responded to slides depicting a feared aversive stimulus. The SD procedure resulted in significantly less reported fear, fewer trials to a criterion level of decrease in subjective fear, and significantly greater decreases in ANS baseline measures. However, measures of behavioral avoidance and measures of decrease in psychophysiological responsivity to the aversive stimuli revealed significant changes within both SD and NRC groups, and no significant differences between the groups, whether or not the groups were equated for number of stimulus presentations. The results, indicating equivalent efficacy and efficiency for the SD and NRC procedures, suggested a limited role for relaxation in systematic desensitization. An extinction or habituation hypothesis was supported at the expense of a counterconditioning hypothesis.     

Can a shuttlebox computer analog be used to condition human avoidance behavior?

Freedman (1990) introduced a computer analog of the shuttlebox paradigm and presented results to show that this analog could be used for studying human avoidance conditioning. In the present study, a first experimental phase was conducted to test how the fact that the tone was considered aversive in the instructions and the intensity of this tone affect avoidance behavior. In a transfer-of-control test phase, it was tested as to whether the warning stimulus presented as a cue to the aversive stimulus had acquired either aversive or informative quality. An effect of instructions was observed for both levels of the auditive stimulus, and a stimulus effect was found for those groups that were given the instructions that described the tone as aversive. In the case of subjects who in the first phase achieved a certain learning criterion, it was recorded how often they in the second phase selected a condition in which the warning signal of the first phase was not presented. No transfer of control was observed. Thus, no positive evidence was found indicating that Freedman’s computer analog could be used for studying human avoidance conditioning.     

The effect of control and predictability in learned helplessness

The present 2 x 2 study deals with the influence of controllability and predictability of an aversive noise stimulus on a subsequent learning task. Eighty-four subjects participated in two experiments. In correspondence with the concept of learned helplessness, controllability was shown to be the dominant factor in the first experiment. In the second experiment, a modified test task was used in which both factors were shown to act in specific ways: The main influence of controllability is upon response measures (latency, omission), whereas unpredictability retardates learning of new predictive connections. The results are discussed in terms of contingency learning.     

Transfer of avoidance responding to a sensory preconditioned cue: Evidence for the role of S-S and R-S knowledge in avoidance learning

In avoidance learning studies, a warning signal (Sd) is directly paired with an aversive unconditioned stimulus (US) unless a particular response is performed. Research by Augustson and Dougher (1997) demonstrated that not only warning signals but also stimuli that are indirectly paired with the aversive event are capable of affecting the avoidance response. In the present study, we extended these results by incorporating a sensory preconditioning paradigm in an avoidance learning procedure. Sensory preconditioning training influenced the selection of avoidance responses in the presence of warning signals that were never paired directly with the aversive events. Moreover, results suggest that the selection of the avoidance responses was based on an integration of knowledge about the relation between the Sd and the US (S-S knowledge) and knowledge about the relation between the avoidance response and the US (R-S knowledge). As the expectancy-based theory of Lovibond (2006) is the only theory of avoidance that incorporates both knowledge structures, the results provide unique support for this theory.     

Second-order avoidance behavior in monkeys

Two monkeys were trained on a three-component multiple schedule using discrete trials. In one component (food), a response terminated a red stimulus and produced food and S(Delta). In the second component (avoidance), a response terminated a green stimulus and avoided shock. In the third component (optional), a response terminated a blue stimulus and produced S(Delta). The consequence of not responding in the blue stimulus, however, was the production of either a food or an avoidance trial. Manipulation of these consequences showed that when food trials were available only a small percent of the time after optional trials, the subjects tended not to respond in the blue, even though this led to an increase in the total number of avoidance trials per day. If only avoidance trials followed as a consequence of not responding in the optional component, the animals terminated the blue stimulus and avoided the avoidance trials. Throughout the experiment both subjects maintained consistently low shock rates (about 10 per day) and these were not affected by the various manipulations. The data suggest that a stimulus associated with avoidance can be a conditioned aversive stimulus and will maintain a more remote avoidance response under certain conditions.     

The effects of vicarious experience and stimulus intensity on pain termination and work avoidance

The purpose of the present investigation was to evaluate the role of vicarious experience in the acquisition of pain termination and work avoidance. Fifty-six experimental subjects were randomly assigned to view a film of a model who either terminated exposure to a pain stimulus and work task after 10 sec (high-avoidant) or 70 sec (low-avoidant). Following the film presentation, subjects were exposed to the pain stimulus and work task. Half of the subjects were randomly chosen to perform the task with a low-intensity pain stimulus (LP) and the other half performed the task while exposed to a high-intensity pain stimulus (HP). The results indicated that subjects in the high-avoidant model conditions (HA) did significantly less work and tolerated the pain stimulus for significantly fewer seconds compared to the low-avoidant model groups (LA). Subjects in the LP groups tolerated the pain stimulus significantly longer and did significantly more work compared to subjects in the HP groups. No significant interaction was observed. The results provide support for the hypothesis that behavioral reactions to pain can be acquired by vicarious experience. Implications for future research are discussed.     

The effects of cued UCS rehearsal on the retention of differential 'fear' conditioning: an experimental analogue of the 'worry' process

This study describes a human electrodermal conditioning experiment in which subjects were asked to mentally rehearse the UCS in a period following initial fear conditioning and prior to a test period involving nonreinforced presentations of the CS. Subjects who were asked to rehearse the UCS retained a differential fear CR during subsequent unreinforced presentations of the CS, but control subjects who were asked to rehearse either a nonaversive event or an aversive event unrelated to the UCS failed to retain the differential CR they had acquired during conditioning. These results suggest that rehearsal of the UCS during periods when CS and UCS are absent can aid the persistence of a fear CR in the absence of further pairings of the CS and UCS. It is argued that these effects can be explained in terms of the effect of UCS rehearsal on the strength and evaluation of the UCS representation. It is also suggested that cued UCS rehearsal might provide a useful procedure for understanding clinical incubation effects and for understanding how the 'worry' process contributes to the maintenance and incubation of fear.     

Evidence for an expectancy-based theory of avoidance behaviour

In most studies on avoidance learning, participants receive an aversive unconditioned stimulus after a warning signal is presented, unless the participant performs a particular response. Lovibond (2006) recently proposed a cognitive theory of avoidance learning, according to which avoidance behaviour is a function of both Pavlovian and instrumental conditioning. In line with this theory, we found that avoidance behaviour was based on an integration of acquired knowledge about, on the one hand, the relation between stimuli and, on the other hand, the relation between behaviour and stimuli.     

Evidence for an expectancy-based theory of avoidance behaviour

In most studies on avoidance learning, participants receive an aversive unconditioned stimulus after a warning signal is presented, unless the participant performs a particular response. Lovibond (2006) recently proposed a cognitive theory of avoidance learning, according to which avoidance behaviour is a function of both Pavlovian and instrumental conditioning. In line with this theory, we found that avoidance behaviour was based on an integration of acquired knowledge about, on the one hand, the relation between stimuli and, on the other hand, the relation between behaviour and stimuli.     

Transformation of avoidance response functions in accordance with same and opposite relational frames

Research on the emergence of human avoidance behavior in the absence of direct contact with an aversive event is somewhat limited. Consistent with work on derived relational responding, the present study sought to investigate the transformation of avoidance response functions in accordance with the relational frames of Same and Opposite. Participants were first exposed to nonarbitrary and arbitrary relational training and testing in order to establish Same and Opposite relations among arbitrary stimuli. The training tasks were; Same-A1-B1, Same-A1-C1, Opposite-A1-B2, Opposite-A1-C2. Next, all possible combinatorially entailed (i.e., B-C and C-B) relations were tested. During the avoidance-conditioning phase, one stimulus (B1) from the relational network signaled a simple avoidance response that cancelled a scheduled presentation of an aversive image and sound. All but one of the participants who met the criteria for conditioned avoidance also demonstrated derived avoidance by emitting the avoidance response in the presence of C1 and the nonavoidance response in the presence of C2. Control participants who were not exposed to relational training and testing did not show derived avoidance. Implications of the findings for understanding clinically significant avoidance behavior are discussed.     

Facilitation and suppression of human loss-avoidance by signaled, unavoidable loss

A 15-sec stimulus followed by unavoidable monetary loss was presented to human subjects who were avoiding loss on a free-operant schedule. As has been observed in studies where shock is the aversive event, initial reactions to the pre-loss stimulus were transient increases in overall and stimulus rates. Unlike shock studies, continued training produced decreased rates, in the presence of the 15-sec stimulus, which were maintained in two of three subjects. Subsequent observations indicated that lowered rates were a function of the subject's rate of avoidance responding, the duration of the stimulus, and the scheduling of avoidable losses. Increasing the duration of the stimulus eliminated lowered rates in the presence of the stimulus and subsequent exposures to conditions which previously produced lowered rates did not result in recovery of the phenomenon. Introduction of the pre-loss stimulus on an extinction baseline (avoidable losses were omitted), however, reinstituted lowered rates. It is proposed that the pre-loss stimulus assumed discriminative control over low rates because responding in the presence of the stimulus was ineffective in avoiding the unavoidable loss. Recovery from lowered rates is attributed to the occurrence of avoidable losses during the stimulus period, and maintenance of lowered rates on the extinction schedule to the omission of such avoidable losses.     

MAINTENANCE FACTORS IN COERCIVE MOTHER-CHILD INTERACTIONS: THE COMPLIANCE AND PREDICTABILITY HYPOTHESES

Two stimulus control processes by which some parent-child dyads occasionally escalate their aversive exchanges into progressively more coercive interactions are described. The compliance hypothesis suggests that aversive actions have instructional properties for the dyad and that parent compliance with such child instructions maintains behavior chains of increasing aversiveness. The predictability hypothesis suggests that social interactions are most likely to function as aversive stimuli in the dyad when delivered in unpredictable fashion by either party and that responses instrumental in reducing dyadic unpredictability maintain aversive behavior chains. Expectations derived from both hypotheses are evaluated in a series of correlational analyses of mother-child interactions obtained in extended baseline observations of three dyads seeking psychological help for severe interactional problems. Results provide tentative support for the predictability hypothesis and suggest important avenues of further research.     

Human, free-operant avoidance of “time out” from monetary reinforcement

To assess the aversive effects of withdrawing monetary reinforcement, human subjects were exposed to a free-operant avoidance procedure in which periods of no reinforcement occurred if the subject failed to respond, and each response postponed withdrawal of reinforcement. Avoidance behavior was developed either through specific instructions about the consequence of responding or through preliminary escape-avoidance training. In all cases, rates of response were found to be a positively accelerated function of decreases in the duration by which responding postponed reinforcement withdrawal. The findings with respect to the function relating avoidance behavior to the interval of postponement were viewed as similar to those obtained when shock is used as the aversive event in free-operant avoidance conditioning.     

Differential involvement of the central amygdala in appetitive versus aversive learning

Understanding the function of the distinct amygdaloid nuclei in learning comprises a major challenge. In the two studies described herein, we used c-Fos immunolabeling to compare the engagement of various nuclei of the amygdala in appetitive and aversive instrumental training procedures. In the first experiment, rats that had already acquired a bar-pressing response to a partial food reinforcement were further trained to learn that an acoustic stimulus signaled either continuous food reinforcement (appetitive training) or a footshock (aversive training). The first training session of the presentation of the acoustic stimulus resulted in significant increases of c-Fos immunolabeling throughout the amygdala; however, the pattern of activation of the nuclei of the amygdala differed according to the valence of motivation. The medial part of the central amygdala (CE) responded, surprisingly, to the appetitive conditioning selectively. The second experiment was designed to extend the aversive versus appetitive conditioning to mice, trained either for place preference or place avoidance in an automated learning system (INTELLICAGE). Again, much more intense c-Fos expression was observed in the medial part of the CE after the appetitive training as compared to the aversive training. These data, obtained in two species and by means of novel experimental approaches balancing appetitive versus aversive conditioning, support the hypothesis that the central nucleus of the amygdala is particularly involved in appetitively motivated learning processes.     

Stigma,staring, and discomfort: A novel-stimulus hypothesis

Three experiments were conducted in order to assess the validity of the novel-stimulus hypothesis as an explanation for why people who are physically different (i.e., novel) are avoided. The hypothesis states that avoidance is mediated by conflict over a desire to stare at novel stimuli and a desire to adhere to a norm against staring when the novel stimulus is another person. In the first two field experiments, subjects viewed photographs of novel (handicapped or pregnant) and familiar (physically normal) people under conditions where staring was sanctioned or not. It was found that staring increased with novelty when staring was unobserved (sanctioned); however, the reverse obtained when an observer was present. In the third experiment, subjects interacted with a crippled, pregnant, or physically normal partner. Half of the subjects were first given the opportunity to observe their partner through a one-way mirror. The reduction in stimulus novelty for this group resulted in reduced avoidance. The question of whether such avoidance of the disabled results from feelings of dislike or disgust as previously suggested, or from discomfort created by novelty, is discussed.     

Blocking and unblocking of conditioned analgesia

Two experiments with rat subjects assessed the blocking phenomenon using inhibition of responding to painful thermal stimulation as an index of conditioned analgesia established through conditioned stimulus (CS)-shock pairings. In Experiment 1, a group of rats receiving the standard blocking procedure ($\text{A+}\text{AB+}$) showed shorter response latencies during a hot plate test of pain sensitivity in the presence of the added CS than groups of rats receiving various blocking control procedures. Experiment 2 replicated the blocking outcome of Experiment 1 and also demonstrated that the addition of a second shock unconditioned stimulus (US) during the compound conditioning phase attenuated the blocking effect; i.e., unblocking was observed. However, the deletion of a second shock US during compound conditioning in a group that had received two shocks on each trial in the first phase of the experiment failed to result in unblocking. These data extend the associative account of conditioned analgesia to situations involving stimulus selection and the implications for the analysis of aversive learning are discussed.     

Interactive learning in the paradise fish (Macropodus opercularis): an ethological interpretation of the second-order conditioning paradigm

This study was aimed at the examination of ‘mental construction’ in paradise fish by interactive learning, which is suggested as an alternative hypothesis for backward or second-order conditioning. Avoidance of goldfish was established in paradise fish by presenting a harmless goldfish (a novel stimulus) after an aversive event (mild electric shocks) in the dark compartment of a shuttle tank. It was found that this avoidance depended on context pre-exposure. Experiment 1 was designed to study the effect of mild shocks on shuttling activity in a familiar context. Experiment 2 aimed at establishing fear-conditioning to the goldfish in a higher-order conditioning paradigm. In the course of training, unpaired stimuli were presented in the dark compartment of the shuttle tank in such a manner that the presentation of mild shocks (20 mA) preceded the encounter with a harmless fish (goldfish). Experiment 3 demonstrated the role of context pre-exposure in interactive learning. Results indicate that (1) while 60 mA shocks resulted in avoidance of the dark compartment, the 20 mA mild shocks affected exploratory behaviour; (2) after pre-exposure to the training environment, paradise fish avoided the dark compartment containing goldfish provided that subjects had previously encountered mild, explorative shocks there; (3) this conditioned fear, a ‘mental construction’ of a potential danger, was proved to be transferable to another context and was consequently aimed specifically at the goldfish, a living being, rather than the training context; (4) the pre-exposure to the shuttle tank was an important part of this training procedure, that is, only subjects habituated to the shuttle tank avoided the goldfish. Results are discussed in the framework of the Interactive Learning Hypothesis, which has been developed as an ethological approach to a higher-order conditioning paradigm. Received: 15 January 1999 / Accepted after revision: 18 August 1999     

Effects of perceived similarity on vicarious emotional conditioning

The present experiment tested the hypothesis that perceived similarity between observers and models enhances vicarious emotional conditioning. Subjects were led to believe that they were either similar to the model in beliefs and attitudes, different from him or were given no information about him. They then underwent a vicarious classical conditioning procedure by witnessing the model express pain reactions in conjunction with a neutral stimulus. Observers developed emotional reactions to the neutral stimulus alone after seeing it paired with modeled pain expressions. Preceived similarity, however, had no significant effect on either the level of vicarious conditioning or the rate of extinction. Subjects who had no information concerning the model displayed stronger autonomic responses to the model's pain expressions, and more frequent and intense autonomic responses to the conditioned stimulus during tests for acquisition and extinction. In correlational analyses, subjects in the latter condition also yielded a significant positive relationship between self-reported arousal and vicarious emotional conditioning. The obtained findings were interpreted in terms of the emotion arousing properties of unfamiliarity.     

Timing in free-operant and discrete-trial avoidance

A procedure (“discrete-trial” avoidance) was devised to differentiate between the two main theories of responding in Sidman's “free-operant” avoidance procedure. One theory, a version of two-factor theory, holds that responding is reinforced by the removal of a conditioned aversive stimulus. The conditioned aversive stimulus is held to be temporal, which accounts for the spaced responding, or timing, that Sidman's procedure produces. The other theory holds that the reinforcement for both responding and timing is shock-frequency reduction. The new procedure eliminated this reinforcement for timing, but retained the conditions for the formation of conditioned aversive temporal stimuli. According to one theory, the new procedure should have sustained timing as well as Sidman's, while according to the other, it should have sustained no timing. The results confirmed neither theory. Timing was found with both procedures, but unequally in degree and kind. Large variations in the precision of timing did not appear to be correlated with successful avoidance for either procedure.