Article

Generalization of instrumentally acquired pain-related avoidance to novel but similar movements using a robotic arm-reaching paradigm

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Abstract

Avoidance is considered a key contributor to the development and maintenance of chronic pain disability, likely through its excessive generalization. This study investigated whether acquired avoidance behavior generalizes to novel but similar movements. Using a robotic arm, participants moved their arm from a starting to a target location via one of three possible movement trajectories. For the Experimental Group, the shortest, easiest trajectory was always paired with pain (T1 = 100% reinforcement/no resistance and deviation). Pain could be partly or completely avoided by choosing increasingly effortful movements (T2 = 50% reinforcement, moderate resistance/deviation; T3 = 0% reinforcement, strongest resistance/largest deviation). A Yoked Group received the same number of painful stimuli irrespective of their own behavior. Outcomes were self-reported fear of movement-related pain, pain-expectancy, avoidance behavior, (maximal deviation from the shortest trajectory), and trajectory choice behavior. We tested generalization to three novel trajectories (G1-3) positioned next to the acquisition trajectories. Whereas acquired fear of movement-related pain and pain-expectancy generalized in the Experimental Group, avoidance behavior did not, suggesting that threat beliefs and high-cost avoidance may not be directly related. The lack of avoidance generalization may be due to a perceived context-switch in the configurations of the acquisition and the generalization phases.

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... Two participants' data were excluded prior to data analysis due to technical difficulties experienced during data collection. Thus, 60 participants were included in the analyses (34 female, M ± SD (range) age = 24.25 ± 5 years (18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)). The sample size was determined by a previous a priori power calculation (using G*Power; α = .05, ...
... Closer inspection of participants' 16 choices during generalization, suggested that the difference between groups was driven by the 17 Experimental Group performing all generalization trajectories relatively equally, whereas the 18 Yoked Group preferred the shortest, least effortful movement trajectory (G1) over the others. 19 Since preference in the Experimental Group did not decrease from the "safest" generalization 20 trajectory (G4) to the "most threatening" one (G1), no avoidance generalization gradient or area 21 shift-like effect (i.e. preference for G4 over G3) was observed. ...
... The current findings align with previous studies investigating generalization of costly pain-24 related avoidance in healthy people. In Glogan et al. 21 , and Glogan, Vandael, et al. 23 , pain-related 25 fear and pain-expectancies generalized, but costly pain-related avoidance did not. Oftentimes showing that healthy participants explore novel movement trajectories, even when they report 72 being fearful of these 21,23 . ...
Article
Pain-related fear and –avoidance crucially contribute to pain chronification. People with chronic pain may adopt costly avoidance strategies above and beyond what is necessary, aligning with experimental findings of excessive fear generalization to safe movements in these populations. Furthermore, recent evidence suggests that, when avoidance is costly, it can dissociate from fear. Here, we investigated whether concurrently measured pain-related fear and costly avoidance generalization correspond in one task. We also explored whether healthy participants avoid excessively despite associated costs, and if avoidance would decrease as a function of dissimilarity from a pain-associated movement. In a robotic arm-reaching task, participants could avoid a low-cost, pain-associated movement trajectory (T+), by choosing a high-cost non-painful movement trajectory (T-), at opposite ends of a movement plane. Subsequently, in the absence of pain, we introduced three movement trajectories (G1-3) between T+ and T-, and one movement trajectory on the side of T- opposite to T+ (G4), linearly increasing in costs from T+ to G4. Avoidance was operationalized as maximal deviation from T+, and as trajectory choice. Fear learning was measured using self-reported pain-expectancy, pain-related fear, and startle eye-blink EMG. Self-reports generalized, both decreasing with increasing distance from T+. In contrast, all generalization trajectories were chosen equally, suggesting that avoidance-costs and previous pain balanced each other out. No effects emerged in the EMG. These results add to a growing body of literature showing that (pain-related) avoidance, especially when costly, can dissociate from fear, calling for a better understanding of the factors motivating, and mitigating, disabling avoidance.
... Most studies rely on instructed avoidance behavior and likely fail to capture the core mechanisms underlying avoidance as overt behavior (75,133,134). To target this issue, pain research addressed costly pain-related fear and avoidance more directly by implementing operant learning paradigms (115,135,136), documenting that sustained avoidance behavior is continued despite being no longer adaptive, and can even increase fear and pain sensitivity (137). It further underscores a key role of threat-related uncertainty, which has recently been identified as a putative vulnerability factor for maladaptive avoidance behavior (138), and may constitute a promising target for behavioral treatments in psychosomatic disorders (115). ...
... Finally, approaches in experimental and clinical research alike should aim at bridging the gap between models applied in laboratory settings and patients' clinical reality and to more closely integrate the concepts of the FAM into the broad field of psychosomatic medicine. To achieve this goal, clinically-relevant and phenomenologically valid models are needed, capturing different facets as well as the specificity of fear and avoidance in psychosomatic disease, as first innovative attempts in the fields of muscoskeletal (115,(135)(136)(137)163) and interoceptive visceral pain (20,110,111,164,165) have previously demonstrated. These experimental settings provide an ideal opportunity to overcome some common limitations of avoidance research, and to operationalize and assess the complex phenomenon of avoidance in its multiple facets, incorporating behavioral, cognitive, but also neural levels (39). ...
... These experimental settings provide an ideal opportunity to overcome some common limitations of avoidance research, and to operationalize and assess the complex phenomenon of avoidance in its multiple facets, incorporating behavioral, cognitive, but also neural levels (39). Rather than artificial losses, clinically-relevant avoidance costs appear promising here, such as the previously implemented increased efforts to achieve a goal (135,158) or a loss of predictability, which increases fear and uncertainty and can demonstrably affect pain-related fear and interoceptive pain experiences (111,164,166). ...
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Avoidance behaviors are shaped by associative learning processes in response to fear of impending threats, particularly physical harm. As part of a defensive repertoire, avoidance is highly adaptive in case of acute danger, serving a potent protective function. However, persistent or excessive fear and maladaptive avoidance are considered key factors in the etiology and pathophysiology of anxiety- and stress-related psychosomatic disorders. In these overlapping conditions, avoidance can increase the risk of mental comorbidities and interfere with the efficacy of cognitive behavioral treatment approaches built on fear extinction. Despite resurging interest in avoidance research also in the context of psychosomatic medicine, especially in conditions associated with pain, disturbed interoception, and disorders of the gut-brain axis, current study designs and their translation into the clinical context face significant challenges limiting both, the investigation of mechanisms involved in avoidance and the development of novel targeted treatment options. We herein selectively review the conceptual framework of learning and memory processes, emphasizing how classical and operant conditioning, fear extinction, and return of fear shape avoidance behaviors. We further discuss pathological avoidance and safety behaviors as hallmark features in psychosomatic diseases, with a focus on anxiety- and stress-related disorders. Aiming to emphasize chances of improved translational knowledge across clinical conditions, we further point out limitations in current experimental avoidance research. Based on these considerations, we propose means to improve existing avoidance paradigms to broaden our understanding of underlying mechanisms, moderators and mediators of avoidance, and to inspire tailored treatments for patients suffering from psychosomatic disorders.
... Such instructions precluded the possibility to examine how costly avoidance is acquired by trial-and-error (c.f. Meulders et al., 2016;Glogan et al., 2020). This might also reduce threat ambiguity, minimizing the effects of individual risk factors on costly CS-avoidance. ...
Article
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Avoidance of learnt fear prevents the onset of a feared stimulus and the threat that follows. In anxiety-related disorders, it turns pathological given its cost and persistence in the absence of realistic threat. The current study examined the acquisition of costly avoidance of learnt fear in healthy individuals (n = 45), via a sensory preconditioning paradigm. Two neutral preconditioning stimuli (PSs) were paired with two neutral conditioned stimuli (CSs). One CS then came to predict an aversive outcome whereas the other CS came to predict safety. In test, participants engaged in stronger avoidance to the PS associated with the fear-related CS than the PS associated with the safety-related CS. Of note, executing behavioural avoidance led to missing out a competing reward, thus rendering avoidance costly. The results also provide preliminary evidence that threat anticipation and a negative change in valence play a role in driving costly avoidance of learnt fear. Future studies should examine how avoidance of learnt fear maintains pathological anxiety.
... Generalization of fear and avoidance behavior becomes a maladaptive learning process when extending to safe situations or safe movements following a better safe than sorry strategy 27,28 . Avoidance behavior can generalize to other movements if it is expected that similar movements will have the same protective effect in that context 11 . In addition, the same behavior can generalize to new contexts in order to ensure safety in novel environments 20 . ...
Article
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When pain persists beyond healing time and becomes a “false alarm” of bodily threat, protective strategies, such as avoidance, are no longer adaptive. More specifically, generalization of avoidance based on conceptual knowledge may contribute to chronic pain disability. Using an operant robotic-arm avoidance paradigm, healthy participants (N=50), could perform more effortful movements in the threat context (e.g. pictures of outdoor scenes) to avoid painful stimuli, whereas no pain occured in the safe context (e.g. pictures of indoor scenes). Next, we investigated avoidance generalization to conceptually related contexts (i.e. novel outdoor/indoor scenes). As expected, participants avoided more when presented with novel contexts conceptually related to the threat context than in novel exemplars of the safe context. Yet, exemplars belonging to one category (outdoor/indoor scenes) were not interchangeable; there was a generalization decrement. Posthoc analyses revealed that contingency-aware participants (n=27), but not non-aware participants (n=23), showed the avoidance generalization effect and also generalized their differential pain-expectancy and pain-related fear more to novel background scenes conceptually related to the original threat context. In contrast, the fear-potentiated startle response was not modulated by context. Perspective: This article provides evidence for contextual modulation of avoidance behavior and its generalization to novel exemplars of the learned categories based on conceptual relatedness. Our findings suggest that category-based generalization is a plausible mechanism explaining why patients display avoidance behavior in novel situations that were never directly associated with pain.
... In consequence, a direct matching with the randomly applied heat stimuli in the modification phase was not possible, also because the duration of the modification phase depended on the participants' behavior. Therefore, we suggest that future studies should introduce a yoked design (e.g., Glogan et al., 2020). Fifth, all results concerning SCR should be interpreted with caution and as hypotheses-generating only as we implemented a rather conservative censoring to the SCR by excluding (instead of replacing) all trials with missing values. ...
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Background: Pain-related fear is critically involved in the development and maintenance of chronic pain. Empirical research suggests a key role of operant learning mechanism, and first experimental paradigms were developed for their investigation within a controlled laboratory setting. We introduce a new virtual reality paradigm with improved ecological validity. Methods: The paradigm evaluated the effects of heat-pain stimuli applied contingent versus non-contingent with large arm movements in naturalistic virtual sceneries. Self-reported pain-related fear and pain expectancy, avoidance behavior, and electrodermal activity were assessed in 42 subjects during an acquisition phase (movements-pain association) and a modification phase (no movement-pain association). Results: Pain applications contingent to arm movements induced a gradual increase in pain-related fear and pain expectancy ratings. Both were continuously and ultimately reduced when the contingency was removed. Avoidance behavior demonstrated no such pattern; time-resolved post-hoc analyses revealed that changes in the avoidance behavior took place very fast within the first trial only. Skin conductance levels resemble the patterns observed for ratings, while skin conductance responses equal behavioral results. Conclusion: Our findings suggest the involvement of two different learning mechanisms in the acquisition and modification of pain-related fear: While affective and cognitive fear components evolve rather slow and more gradually, avoidance behavior seems to change much faster, both of which were accompanied by corresponding changes in physiological arousal. These results emphasize the importance of avoidance behavior in chronic pain development, maintenance and its therapy. The introduced virtual reality paradigm allows to examine such avoidance behavior in an ecological valid environment.
... Participants were instructed to verbally rate each of these stimuli on a 0 to 10 numeric rating scale (NRS) with 0 meaning "you felt nothing"; 3 referring to a sensation that "starts to be painful but can easily be tolerated"; and 10 being the "worst tolerable pain". As in previous studies [18,36] intertrial interval varied randomly between 600 and 1000 ms with a mean of 800 ms. Half of the trials were congruent with all arrows pointing into the same direction ("<<<<<" or ">>>>>"), while the other half was incongruent with the middle arrow pointing in the opposite direction compared to the flanking arrows ("<<><<" or ">><>>"). ...
Article
Pain can be considered as a signal of "bodily error": Errors put organisms at danger and activate behavioral defensive systems. If the error is of physical nature, pain is the warning signal that motivates protective action such as avoidance behavior to safeguard our body's integrity. Interestingly, an important component of neural error processing, the error-related negativity (ERN), has been found to be related to avoidance in anxiety disorders. The present study is the first to extend these findings to pain and investigate the relationship between ERN and pain-related avoidance behavior. It was hypothesized that individuals with larger ERN amplitudes would show more pain-related avoidance behavior and would be more persistent in their avoidance despite changes in the environment. Fifty-three healthy individuals performed the Eriksen Flanker task during which their brain activity upon correct and erroneous motor responses was recorded by means of high-density electroencephalography. Avoidance behavior was assessed with an arm-reaching task using the HapticMaster robot arm. Results showed that, in contrast to our hypothesis, avoidance was not related to ERN amplitudes. Surprisingly, persons with elevated ERN amplitudes showed low levels of avoidance specifically during early acquisition trials. In contrast to earlier findings in anxiety disorders, individuals with elevated ERN amplitudes did not engage in more pain-related avoidance behavior. In fact, the opposite pattern was found at the start of acquisition: individuals with higher compared to lower ERN amplitudes were slower in learning to avoid pain. Replications and future studies on the relationship between ERN and avoidance behavior are needed.
... This could have created some ambiguity, because for a number of participants this might have been sufficient evidence that T2 is a dangerous movement, and they refrained from checking further in subsequent trials [2]. Although avoidance may not have been affected, a potential confound in this paradigm is the placement of T2 close to T1 (generalisation of the threat based on perceptual/proprioceptive similarity with T1) and to the left of T3 (rule-based generalisation) [11]. Placing T2 to the right of T3 may have been better to control for the potential generalisation. ...
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The fear-avoidance model of chronic pain predicts that catastrophic (mis)interpretation of pain elicits pain-related fear that in turn may spur avoidance behaviour leading to chronic pain disability. Here we investigated whether performing a movement to avoid a painful stimulus in the context of a novel movement increases threat and pain-related fear towards this novel movement, and whether avoidance behaviour persisted when given the choice between performing the acquired movement to avoid a painful stimulus or an alternative, novel movement. Applying a robotic arm-reaching task, participants could choose between two movements to reach a target location: a short, but painful movement trajectory, or a longer non-painful movement trajectory. After avoidance acquisition, the option to choose the painful trajectory was removed. The Experimental Group (N=50) could choose between the longest trajectory or a novel intermediate trajectory, whereas the Control Group (N=50) was allowed to only perform the novel trajectory. In a final test, participants of both groups were allowed to choose any of the three trajectories. Post-acquisition, Experimental Group participants showed elevated pain-expectancy and pain-related fear towards the novel trajectory, compared to the Control Group. During test, the Experimental Group participants persisted in performing the longest pain-free (avoidance) trajectory, and were less likely to choose the novel trajectory. In addition, these participants maintained higher levels of pain-related fear for the novel trajectory compared to the Control Group. These findings suggest that avoidance in the context of other neutral activities/movements may lead to the development and maintenance of threat appraisals and irrational fears.
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Elevated levels of fear and avoidance are core symptoms across the anxiety disorders. It has long been known that fear serves to motivate avoidance. Consequently, fear extinction has been the primary focus in pre-clinical anxiety research for decades, under the implicit assumption that removing the motivator of avoidance (fear) would automatically mitigate the avoidance behaviors as well. Although this assumption has intuitive appeal, it has received little scientific scrutiny. The scarce evidence from animal studies is mixed, while the assumption remains untested in humans. The current study applied an avoidance conditioning protocol in humans to investigate the effects of fear extinction on the persistence of low-cost avoidance. Online danger-safety ratings and skin conductance responses documented the dynamics of conditioned fear across avoidance and extinction phases. Anxiety- and avoidance-related questionnaires explored individual differences in rates of avoidance. Participants first learned to click a button during a predictive danger signal, in order to cancel an upcoming aversive electrical shock (avoidance conditioning). Next, fear extinction was induced by presenting the signal in the absence of shocks while button-clicks were prevented (by removing the button in Experiment 1, or by instructing not to click the button in Experiment 2). Most importantly, post-extinction availability of the button caused a significant return of avoidant button-clicks. In addition, trait-anxiety levels correlated positively with rates of avoidance during a predictive safety signal, and with the rate of pre- to post-extinction decrease during this signal. Fear measures gradually decreased during avoidance conditioning, as participants learned that button-clicks effectively canceled the shock. Preventing button-clicks elicited a sharp increase in fear, which subsequently extinguished. Fear remained low during avoidance testing, but danger-safety ratings increased again when button-clicks were subsequently prevented. Together, these results show that low-cost avoidance behaviors can persist following fear extinction and induce increased threat appraisal. On the other hand, fear extinction did reduce augmented rates of unnecessary avoidance during safety in trait-anxious individuals, and instruction-based response prevention was more effective than removal of response cues. More research is needed to characterize the conditions under which fear extinction might mitigate avoidance.
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This chapter reviews the recent research on motivation, beliefs, values, and goals, focusing on developmental and educational psychology. The authors divide the chapter into four major sections: theories focused on expectancies for success (self-efficacy theory and control theory), theories focused on task value (theories focused on intrinsic motivation, self-determination, flow, interest, and goals), theories that integrate expectancies and values (attribution theory, the expectancy-value models of Eccles et al., Feather, and Heckhausen, and self-worth theory), and theories integrating motivation and cognition (social cognitive theories of self-regulation and motivation, the work by Winne & Marx, Borkowski et al., Pintrich et al., and theories of motivation and volition). The authors end the chapter with a discussion of how to integrate theories of self-regulation and expectancy-value models of motivation and suggest new directions for future research.
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Avoidance is a key characteristic of adaptive and maladaptive fear. Here, we review past and contemporary theories of avoidance learning. Based on the theories, experimental findings and clinical observations reviewed, we distil key principles of how adaptive and maladaptive avoidance behavior is acquired and maintained. We highlight clinical implications of avoidance learning theories and describe intervention strategies that could reduce maladaptive avoidance and prevent its return. We end with a brief overview of recent developments and avenues for further research.
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Increasing evidence supports the notion that pain-related fear plays a key role in the transition from acute to chronic pain. Recent experimental data show that associative learning processes are involved in the acquisition of pain-related fear. An intriguing yet underinvestigated question entails how spreading of pain-related fear in chronic pain occurs. In a voluntary movement paradigm in which one arm movement (CS+) was followed by a painful stimulus and another was not (CS-) in the predictable group and painful stimuli were delivered during the intertrial interval (context alone) in the unpredictable group, we tested generalization of fear to six novel generalization movements (GSs) with varying levels of similarity between the original CS+ movement and CS- movement. Healthy participants (N = 58) were randomly assigned to the predictable or unpredictable group. Fear was measured via verbal ratings and eyeblink startle responses. Results indicated that cued pain-related fear spreads selectively to novel movements that are proprioceptively more similar to the CS+ than to those similar to the CS- in the predictable group, but not in the unpredictable group. This is the first study to demonstrate a generalization gradient of cued pain-related fear. However, this effect was only present in the startle eyeblink responses, but not in the verbal ratings. Taken together, this paradigm represents a novel tool to scrutinize the largely understudied phenomenon of the spreading of fear and avoidance in patients with chronic musculoskeletal pain and mapping possible pathological differences in generalization gradients and the spreading of pain in patients as compared with healthy controls.
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Recent research on classical fear-conditioning in the anxiety disorders has identified overgeneralization of conditioned fear as an important conditioning correlate of anxiety pathology. Unfortunately, only one human neuroimaging study of classically conditioned-fear generalization has been conducted, and the neural substrates of this clinically germane process remain largely unknown. The current generalization study employs a clinically validated generalization gradient paradigm, modified for the fMRI environment, to identify neural substrates of classically conditioned generalization that may function aberrantly in clinical anxiety. Stimuli include five rings of gradually increasing size with extreme sizes serving as cues of conditioned danger (CS+) and safety (CS-). The three intermediately sized rings serve as generalization stimuli (GSs) and create a continuum-of-size from CS+ to CS-. Results demonstrate positive generalization gradients, reflected by declines in responding as the presented stimulus differentiates from CS+, in bilateral anterior insula, dorsomedial prefrontal cortex, and bilateral inferior parietal lobule. Conversely, negative gradients, reflected by inclines in responding as the presented stimulus differentiates from CS+ were instantiated in bilateral ventral hippocampus, ventromedial prefrontal cortex, and precuneus cortex. These results, as well as those from connectivity analyses, are discussed in relation to a working neurobiology of conditioned generalization centered on the hippocampus.
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Predictions about sensory input exert a dominant effect on what we perceive, and this is particularly true for the experience of pain. However, it remains unclear what component of prediction, from an information-theoretic perspective, controls this effect. We used a vicarious pain observation paradigm to study how the underlying statistics of predictive information modulate experience. Subjects observed judgments that a group of people made to a painful thermal stimulus, before receiving the same stimulus themselves. We show that the mean observed rating exerted a strong assimilative effect on subjective pain. In addition, we show that observed uncertainty had a specific and potent hyperalgesic effect. Using computational functional magnetic resonance imaging, we found that this effect correlated with activity in the periaqueductal gray. Our results provide evidence for a novel form of cognitive hyperalgesia relating to perceptual uncertainty, induced here by vicarious observation, with control mediated by the brainstem pain modulatory system.
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In Study 1, the Pain Catastrophizing Scale (PCS) was administered to 425 undergraduates. Analyses yielded a three component solution comprising (a) rumination, (b) magnification, and (c) helplessness. In Study 2, 30 undergraduate participants were classified as catastrophizers (n = 15) or noncatastrophizers (n = 15) on the basis of their PCS scores and participated in an cold pressor procedure. Catastrophizers reported significantly more negative pain-related thoughts, greater emotional distress, and greater pain intensity than noncatastrophizers. Study 3 examined the relation between PCS scores, negative pain-related thoughts, and distress in 28 individuals undergoing an aversive electrodiagnostic medical procedure. Catastrophizers reported more negative pain-related thoughts, more emotional distress, and more pain than noncatastrophizers. Study 4 examined the relation between the PCS and measures of depression, trait anxiety, negative affectivity, and fear of pain. Analyses revealed moderate correlations among these measures, but only the PCS contributed significant unique variance to the prediction of pain intensity.
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Controllable stress, modeled by escapable shock (ES), can produce significant alterations in post-stress sleep, including increased rapid eye movement (REM) sleep. Recent work has demonstrated that post-stress sleep may be influenced by stressor predictability, modeled by predictive auditory cues. In this study, we trained mice with ES, either signaled (SES) or unsignaled (UES) by auditory cues, and investigated the effects of predictability on escape learning and sleep associated with ES. Adult male BALB/cJ mice were implanted for recording electroencephalography and activity via telemetry. After the mice recovered from surgery, baseline sleep recordings were obtained. The mice were then randomly assigned to SES and UES conditions. Both groups had control over the duration of footshocks (0.5 mA; 5.0 sec maximum duration) by moving to the non-occupied chamber in a shuttlebox. SES mice were presented tones (90 dB, 2 kHz, 10 sec maximum duration) that started 5.0 sec prior to and co-terminated with footshocks. UES mice were presented identical tones that were not synchronized to shock presentation. ES training continued for 2 consecutive days (EST1 and EST2) with 20 footshock presentations (1 min inter-stimulus intervals). Seven days after EST2, the animals were re-exposed to the training chamber (context) alone for 30 min. Escape latency was used to determine successful or unsuccessful escape learning. Sleep was scored for 20 h for baseline and on each treatment day. Freezing in the training context was scored as a behavioral index of fear. Nine of 14 SES mice successfully learned escape (SESl), and 5 failed to learn escape (SESf). Compared with baseline, SESl mice, but not SESf mice, showed significantly increased post-shock REM. All UES mice learned escape and showed enhanced post-shock REM. Freezing and sleep did not differ among groups on the context re-exposure day. The results indicate that information available in a stressful situation can affect an animal's ability to learn an appropriate response and post-stress sleep. CITATION: Machida M; Yang L; Wellman LL; Sanford LD. Effects of stressor predictability on escape learning and sleep in mice. 2013;36(3):421-430.
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In Study I, the Pain Catastrophizing Scale (PCS) was administered to 425 undergraduates. Analyses yielded a three component solution comprising (a) rumination, (b) magnification, and (c) helplessness. In Study 2, 30 undergraduate participants were classified as catastrophizers ( n = 15) or noncatastrophizers ( n = 15) on the basis of their PCS scores and participated in a cold pressor procedure. Catastrophizers reported significantly more negative pain-related thoughts, greater emotional distress, and greater pain intensity than noncatastrophizers. Study 3 examined the relation between PCS scores, negative pain-related thoughts, and distress in 28 individuals undergoing an aversive electrodiagnostic medical procedure. Catastrophizers reported more negative pain-related thoughts, more emotional distress, and more pain than noncatastrophizers. Study 4 examined the relation between the PCS and measures of depression, trait anxiety, negative affectivity, and fear of pain. Analyses revealed moderate correlations among these measures, but only the PCS contributed significant unique variance to the prediction of pain intensity. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
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Avoidance of threatening or unpleasant events is usually an adaptive behavioural strategy. Sometimes, however, avoidance can become chronic and lead to impaired daily functioning. Excessive threat-avoidance is a central diagnostic feature of anxiety disorders, yet little is known about whether avoidance acquired in the absence of a direct history of conditioning with a fearful event differs from directly learned avoidance. In the present study, we tested whether avoidance acquired indirectly via verbal instructions and symbolic generalization result in similar levels of avoidance behaviour and threat-beliefs to avoidance acquired after direct learning. Following fear conditioning in which one conditioned stimulus was paired with shock (CS+) and another was not (CS-), participants either learned or were instructed to make a response that cancelled impending shock. Three groups were then tested with a learned CS+ and CS- (learned group), instructed CS+ (instructed group), and generalized CS+ (derived group) presentations. Results showed similar levels of avoidance behaviour and threat-belief ratings about the likelihood of shock across each of the three pathways despite the different mechanisms by which they were acquired. Findings have implications for understanding the aetiology of clinical avoidance in anxiety.
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The first aim of this study was to evaluate the reliability and validity of one version of the PANAS that is widely used in Flanders. In a large nonclinical sample (N=3499), the PANAS showed solid psychometric properties. Sex differences appeared: men scored significantly higher on Positive Affect (PA), but significantly lower on Negative Affect (NA), in comparison with women. Six models were tested with Confirmatory Factor Analysis (CFA). The best-fitting model consisted of two correlated factors corresponding to the PA and NA scales and permitted correlated error. Consequently the hypothesis of complete independence between PA and NA must be rejected. In a second part, we compared our version with a Dutch version (Peeters, Ponds & Vermeeren, 1996). Both translations differed regarding nine items. Our analysis confirmed the psychometric properties of the latter version, and CFA indicated the same model as best-fitting model. Inspection on the item level revealed no considerable differences between the two versions.
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This review addresses recent developments in fear of movement-related pain and avoidance research, adopting a contemporary learning approach focusing on cognitive, emotional, and behavioral factors, and emphasizing the role of the motivational context including pain-avoidance goals but also other valued life goals. We particularly demonstrated the role of classical conditioning in the acquisition, generalization, and extinction of fear of movement-related pain, and how safety-seeking behavior during exposure-based treatment may hamper genuine extinction causing relapse. We further highlighted the importance of newly developed methods to study operant conditioning of behavioral avoidance itself, and its relationship with individual vulnerability factors (e.g. catastrophizing) and resiliencies (e.g. positive affect) to further our understanding of mechanisms underlying the development and persistence of chronic pain disability.
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Unlabelled: Successful adjustment to dynamic environments requires the simultaneous pursuit of multiple goals. However, the pursuit of multiple goals may bring about goal conflict. Despite evidence indicating that goal conflict can have a detrimental effect on subjective well-being, little is known about the effects of goal competition in the context of pain. This experiment investigated whether different types of goal competition increase pain-related fear and slow pain-related decision-making. Forty-six participants completed a cross-directional movement task in which they learned to associate movements in 1 direction (eg, left) with pain, and movements in the opposite direction (eg, right) with safety; and that movements in other directions (eg, up and down) were associated with reward and loss of reward, respectively. In the test phase, both phases were combined, creating different types of goal competition. The results showed that participants were most afraid of movements associated with 2 concurrent avoidance goals, and the least afraid of movements associated with approach-approach competition. Additionally, participants were slower in making a choice when presented with an avoidance-avoidance competition compared with approach-approach and avoidance-approach competition. These findings suggest that avoidance-avoidance competition increased fear and slowed decision-making compared with other types of competition. Perspective: This study provides experimental evidence for the differential effects of various goal conflicts on pain-related fear and decision-making. This knowledge may improve our understanding of patients' behavior when experiencing goal conflict and may contribute to improving treatments by addressing multiple goals patients are pursuing, and not just pain avoidance/reduction.
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Ample empirical evidence endorses the role of associative learning in pain-related fear acquisition. Nevertheless, research typically focused on self-reported and psychophysiological measures of fear. Avoidance, which is overt behavior preventing the occurrence of an aversive (painful) stimulus, has been largely neglected so far. Therefore, we aimed to fill this gap and developed an operant conditioning procedure for pain-related avoidance behavior.Participants moved their arm to a target location using the HapticMaster, a 3 degrees-of-freedom, force-controlled robotic arm. Three movement trajectories led to the target location. If participants in the Experimental Group took the shortest/easiest trajectory, they always received a painful stimulus (T1=100% reinforcement; no resistance). If they deviated from this trajectory, the painful stimulus could be partly or totally prevented (T2=50% reinforcement; T3=0% reinforcement), but more effort was needed (T2=moderate resistance and deviation; T3=strongest resistance and largest deviation). The Yoked Group received the same reinforcement schedule irrespective of their own behavior. During the subsequent extinction phase no painful stimuli were delivered. Self-reported pain-expectancy and pain-related fear were assessed, and avoidance behavior was operationalized as the maximal distance from the shortest trajectory.During acquisition, the Experimental Group reported more pain-related fear and pain-expectancy to T1 vs. T2 vs. T3, and deviated more from the shortest trajectory than the Yoked Group. During subsequent extinction, avoidance behavior, self-reported fear and pain-expectancy decreased significantly, but conditioned differences persisted despite the absence of painful stimuli.To conclude, this operant learning task might provide a valid paradigm to study pain-related avoidance behavior in future studies.
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In chronic musculoskeletal pain, avoidance behavior is a prominent behavioral characteristic that can manifest itself in various ways. It is also considered a crucial component in the development and maintenance of chronic pain-related disability, supposedly fueled by pain-related fear and catastrophic beliefs. Despite the frequent occurrence of avoidance behavior and its potential impact on quality of life, relatively little research has been dedicated to the nature of avoidance in chronic pain and its assessment, leaving its underlying mechanisms poorly understood. In the current paper, we stipulate some of the existing parallels between chronic pain research and more basic fear and anxiety research inspired by modern learning theories. After a brief introduction, we discuss avoidance theories that are likely apt to be applied to chronic pain, including avoidance as a response that can affect fear responding, and the role of avoidant decision making and motivational context. Finally, we will outline how these theories may impact clinical treatment.
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Anomalies in fear learning, such as the failure to inhibit fear to safe stimuli, lead to sustained anxiety, which in turn may augment pain. In the same vein, stimulus generalization is adaptive as it enables individuals to extrapolate the predictive value of one stimulus to similar stimuli. However, when fear spreads in an unbridled way to novel technically safe stimuli, stimulus generalization becomes maladaptive and may lead to dysfunctional avoidance behaviors and culminate in severe pain disability. In a voluntary movement conditioning paradigm, we compared the acquisition and generalization of pain-related fear in fibromyalgia patients (FM) and healthy controls (HC). During acquisition, participants received predictable pain in one context (i.e., one movement predicts pain, another does not), and unpredictable pain in another (i.e., pain never contingent upon movement). Fear generalization to novel movements (resembling the original painful or non-painful movement) was tested in both contexts. Results indicated that the FM group showed slower differential acquisition of pain-related fear in the predictable context, and more contextual pain-related fear in the unpredictable context. Fear of movement-related pain spreads selectively to novel movements similar to the original painful movement, and not to those resembling the non-painful movement in the HC, but non-differential fear generalization was observed in FM. As expected, in the unpredictable context, we also observed non-differential fear generalization; this effect was more pronounced in FM. Given the status of overgeneralization as a plausible transdiagnostic pathogenic marker, we believe this research might increase our knowledge about the pathogenesis of musculoskeletal widespread pain.
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Fear generalization, in which conditioned fear responses generalize or spread to related stimuli, is a defining feature of anxiety disorders. The behavioral consequences of maladaptive fear generalization are that aversive experiences with one stimulus or event may lead one to regard other cues or situations as potential threats that should be avoided, despite variations in physical form. Theoretical and empirical interest in the generalization of conditioned learning dates to the earliest research on classical conditioning in nonhumans. Recently, there has been renewed focus on fear generalization in humans due in part to its explanatory power in characterizing disorders of fear and anxiety. Here, we review existing behavioral and neuroimaging empirical research on the perceptual and non-perceptual (conceptual and symbolic) generalization of fear and avoidance in healthy humans and patients with anxiety disorders. The clinical implications of this research for understanding the etiology and treatment of anxiety is considered and directions for future research described.
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Unlabelled: Contingency learning, in particular the formation of danger beliefs, underpins conditioned fear and avoidance behavior, yet equally important is the formation of safety beliefs. That is, when threat beliefs and accompanying fear/avoidance spread to technically safe cues, it might cause disability. Indeed, such over generalization has been advanced as a trans-diagnostic pathologic marker, but it has not been investigated in chronic pain. Using a novel hand pain scenario contingency learning task, we tested the hypotheses that chronic hand pain patients demonstrate less differential pain expectancy judgments because of poor safety learning and demonstrate broader generalization gradients than healthy controls. Participants viewed digitized 3-dimensional hands in different postures presented in random order (conditioned stimulus [CS]) and rated the likelihood that a fictive patient would feel pain when moving the hand into that posture. Subsequently, the outcome (pain/no pain) was presented on the screen. One hand posture was followed by pain (CS+), another was not (CS-). Generalization was tested using novel hand postures (generalization stimuli) that varied in how similar they were to the original conditioned stimuli. Patients, but not healthy controls, demonstrated a contingency learning deficit determined by impaired safety learning, but not by exaggerated pain expectancy toward the CS+. Patients showed flatter, asymmetric generalization gradients than the healthy controls did, with higher pain expectancy for novel postures that were more similar to the original CS-. The results clearly uphold our hypotheses and suggest that contingency learning deficits might be important in the development and maintenance of the chronic pain-related disability. Perspective: Chronic hand pain patients demonstrate 1) reduced differential contingency learning determined by a lack of safety belief formation, but not by exaggerated threat belief formation, and 2) flatter, asymmetric generalization gradients than the healthy controls.
Article
Fear-conditioning experiments in the anxiety disorders focus almost exclusively on passive-emotional, Pavlovian conditioning, rather than active-behavioral, instrumental conditioning. Paradigms eliciting both types of conditioning are needed to study maladaptive, instrumental behaviors resulting from Pavlovian abnormalities found in clinical anxiety. One such Pavlovian abnormality is generalization of fear from a conditioned danger-cue (CS+) to resembling stimuli. Though lab-based findings repeatedly link overgeneralized Pavlovian-fear to clinical anxiety, no study assesses the degree to which Pavlovian overgeneralization corresponds with maladaptive, overgeneralized instrumental-avoidance. The current effort fills this gap by validating a novel fear-potentiated startle paradigm including Pavlovian and instrumental components. The paradigm is embedded in a computer game during which shapes appear on the screen. One shape paired with electric-shock serves as CS+, and other resembling shapes, presented in the absence of shock, serve as generalization stimuli (GSs). During the game, participants choose whether to behaviorally avoid shock at the cost of poorer performance. Avoidance during CS+ is considered adaptive because shock is a real possibility. By contrast, avoidance during GSs is considered maladaptive because shock is not a realistic prospect and thus unnecessarily compromises performance. Results indicate significant Pavlovian-instrumental relations, with greater generalization of Pavlovian fear associated with overgeneralization of maladaptive instrumental-avoidance.
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Previous research has suggested that changing the context after instrumental (operant) conditioning can weaken the strength of the operant response. That result contrasts with the results of studies of Pavlovian conditioning, in which a context switch often does not affect the response elicited by a conditioned stimulus. To begin to make the methods more similar, Experiments 1-3 tested the effects of a context switch in rats on a discriminated operant response (R; lever pressing or chain pulling) that had been reinforced only in the presence of a 30-s discriminative stimulus (S; tone or light). As in Pavlovian conditioning, responses and reinforcers became confined to presentations of the S during training. However, in Experiment 1, after training in Context A, a switch to Context B caused a decrement in responding during S. In Experiment 2, a switch to Context B likewise decreased responding in S when Context B was equally familiar, equally associated with reinforcement, or equally associated with the training of a discriminated operant (a different R reinforced in a different S). However, there was no decrement if Context B had been associated with the same response that was trained in Context A (Experiments 2 and 3). The effectiveness of S transferred across contexts, whereas the strength of the response did not. Experiment 4 found that a continuously reinforced response was also disrupted by context change when the same response manipulandum was used in both training and testing. Overall, the results suggest that the context can have a robust general role in the control of operant behavior. Mechanisms of contextual control are discussed. (PsycINFO Database Record (c) 2013 APA, all rights reserved).
Article
According to many conditioning accounts of clinical anxiety, the central pathogen can be found in aberrant acquisition or extinction of learned fear to neutral stimuli (i.e., conditioned stimuli [CS]) paired with an aversive unconditioned stimulus (US).While overresponding to the CS is an important candidate source of anxiety pathology, both clinical observation and mounting experimental data implicate generalization of fear to stimuli resembling the CS as an equally promising candidate (e.g., Grillon & Morgan, 1999; Lissek et al., 2005; Lissek et al., 2010; Mineka & Zinbarg, 1996). Important to the current issue on ‘‘Trauma and Memory,’’ generalization of fear to stimuli resembling those present during a traumatic event is a core feature of the posttraumatic stress response (American Psychiatric Association, 2000) and is likely influenced by conditioning-dependent modifications to the neural representation of the CS stored in memory. The current paper (1) summarizes the connection between conditioned-fear generalization and pathologic anxiety including a recent empirical example demonstrating the link and (2) explores memorial substrates of conditioned generalization and the ways they are related to overgeneralization of the kind seen in anxiety pathology. (PsycINFO Database Record (c) 2014 APA, all rights reserved)
Article
This chapter describes Pavlovian conditioning as the transfer of control of reflexes (unconditioned responses or URs) from stimuli that elicit them unconditionally (USs) to other stimuli that normally are incapable of eliciting them. Although auditory cues seldom elicit substantial salivation spontaneously, a tone provokes that response if it consistently predicts food delivery. This new-found control of salivation by the tone is typically attributed to the acquisition of some association or potentiated connection between the CS and US pathways: by virtue of that association, the CS becomes a substitute elicitor of activity along some portion of the US-UR pathway. This is often described as the CS's “activating a representation of the US”. Another behavioral control function occasionally ascribed to Pavlovian CSsis modulation. Rather than acquiring its own ability to elicit behavior usually controlled by another reflex system, a Pavlovian CS influences the efficacy of the normal elicitor of a response. The chapter is concerned with a particular modulatory function of CSs in rats solutions of elementary conditional discriminations, in which one CS modifies the efficacy of Pavlovian associations between other cues and the US. This function is called as occasion setting, which is readily distinguished from elicitation both conceptually and empirically, and perhaps anatomically as well. Furthermore, this occasion-setting function involves a hierarchical, multilayered organization of representations of events and relations and thus may aid the expansion of the domain of Pavlovian accounts of behavior.
Article
In recent studies of the structure of affect, positive and negative affect have consistently emerged as two dominant and relatively independent dimensions. A number of mood scales have been created to measure these factors; however, many existing measures are inadequate, showing low reliability or poor convergent or discriminant validity. To fill the need for reliable and valid Positive Affect and Negative Affect scales that are also brief and easy to administer, we developed two 10-item mood scales that comprise the Positive and Negative Affect Schedule (PANAS). The scales are shown to be highly internally consistent, largely uncorrelated, and stable at appropriate levels over a 2-month time period. Normative data and factorial and external evidence of convergent and discriminant validity for the scales are also presented. (PsycINFO Database Record (c) 2010 APA, all rights reserved)
Article
Recent evidence indicates that pain-related fear can be acquired through associative learning. In the clinic, however, spreading of fear and avoidance is observed beyond movements/activities that were associated with pain during the original pain episode. One mechanism accounting for this spreading of fear is stimulus generalization. In a voluntary movement-conditioning paradigm, healthy participants received predictable pain (ie, one movement predicts pain, another does not) in one context, and unpredictable pain in another context. The former procedure is known to induce cued pain-related fear to the painful movement, whereas the latter procedure generates contextual pain-related fear. In both experimental pain contexts, we subsequently tested fear generalization to novel movements (having either proprioceptive features in common with the original painful movement or nonpainful movement). Results indicated that in the predictable pain context, pain-related fear spreads selectively to novel movements proprioceptively related to the original painful movement, and not to those resembling the original nonpainful movement. In the unpredictable context, nondifferential fear generalization was observed, suggesting persistent contextual pain-related fear and poor safety learning. These data illustrate that spreading of pain-related fear is fostered by previously acquired movement-pain contingencies. Based on recent advances in anxiety research, we proposed an innovative approach conceptualizing predictable pain as a laboratory model for fear of movement in regional musculoskeletal pain, and unpredictable pain generating contextual pain-related fear as a prototype of widespread musculoskeletal pain. Consequently, fear generalization might play an important role in spreading of pain-related fear and avoidance behavior in regional and widespread musculoskeletal pain.
Article
Background and objectives: Human fear conditioning is widely regarded as one of the prime paradigms for the study of fear and anxiety disorders. We provide an evaluation of a commonly used subjective measure in the human fear conditioning paradigm, namely the US-expectancy measurement. Methods: We assess the validity of US-expectancy with respect to conditions of pathological fear and anxiety using four established criteria for scrutiny of a laboratory test or model (i.e., face validity, diagnostic validity, predictive validity, construct validity). Results: Arguably, there is sufficient evidence for the face validity, diagnostic validity, predictive validity and construct validity of the US-expectancy measure. Limitations: Presumed limitations of the US-expectancy measure, including its susceptibility to experimental demand and memory bias, are discussed. Conclusions: The US-expectancy measure is a valuable measurement method that can be effectively used in research that aims to enhance our understanding of fear and anxiety disorders.
Article
Latency of response and running time were measured in learning experiments involving a simple running response. Four matched groups of 13 rats each were used: I, reinforcement with every one of 16 trials; II, reinforcement in one half of the 16 trials; III, reinforcement with every one of 8 trials; IV, temporally spaced reinforcement with every one of the 8 trials. The extinction trials were separated from the acquisition series in all cases by a 24 hr. period. The average response time in the acquisition series was significantly shorter for Group I than for the other three groups. Retention, measured by comparing the last acquisition trial with the first extinction trial 24 hours later, was nearly complete for all groups except I, which evinced significant increase in average response time. The number of extinction trials required before the 3-minute non-response criterion was reached was not significantly different for the 4 groups. The theoretical meaning of these results is discussed. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
Summarizes the major lines of evidence that demonstrate a dissociation or desynchrony between measures of fear and avoidance responding. The evidence bearing on the role of fear in theories of avoidance learning and extinction is reviewed and critically evaluated. In addition, research is discussed regarding the determinants of fear over the course of avoidance acquisition, flooding, and extinction. Particular emphasis is placed on discussing the extent to which fear extinction is necessary and/or sufficient for avoidance response extinction with conventional extinction procedures and with response prevention techniques. (3½ p ref) (PsycINFO Database Record (c) 2012 APA, all rights reserved)
Article
This paper presents the development and validation of a self-report measure of emotional distress tolerance. The initial scale was developed in Study 1 (N = 642). The scale evinced expected relations with other measures of affective functioning, supporting its convergent and discriminant validity. Criterion validity was supported by significant negative associations with substance use coping but not enhancement motives. Study 2 (N = 823), extended the results of the initial factor analysis, indicating that the Distress Tolerance Scale (DTS) contains four first-order factors, which are indicators of a single second-order general distress tolerance factor. Study 2 indicated that the DTS was stable over a 6-month interval and the DTS was prospectively associated with alcohol problems among men. In both studies, males reported significantly higher levels of distress tolerance than women.
Article
The fear-avoidance (FA) model of chronic pain describes how individuals experiencing acute pain may become trapped into a vicious circle of chronic disability and suffering. We propose to extend the FA model by adopting a motivational perspective on chronic pain and disability. A narrative review. There is ample evidence to support the validity of the FA model as originally formulated. There are, however, some key challenges that call for a next generation of the FA model. First, the FA model has its roots in psychopathology, and investigators will have to find a way to account for findings that do not easily fit within such framework. Second, the FA model needs to address the dynamics and complexities of disability and functional recovery. Third, the FA model should incorporate the idea that pain-related fear and avoidance occurs in a context of multiple and often competing personal goals. To address these 3 key challenges, we argue that the next generation of the FA model needs to more explicitly adopt a motivational perspective, one that is built around the organizing powers of goals and self-regulatory processes. Using this framework, the FA model is recast as capturing the persistent but futile attempts to solve pain-related problems to protect and restore life goals.
Article
Unlabelled: In 2008, according to the Medical Expenditure Panel Survey (MEPS), about 100 million adults in the United States were affected by chronic pain, including joint pain or arthritis. Pain is costly to the nation because it requires medical treatment and complicates treatment for other ailments. Also, pain lowers worker productivity. Using the 2008 MEPS, we estimated 1) the portion of total U.S. health care costs attributable to pain; and 2) the annual costs of pain associated with lower worker productivity. We found that the total costs ranged from $560 to $635 billion in 2010 dollars. The additional health care costs due to pain ranged from $261 to $300 billion. This represents an increase in annual per person health care costs ranging from $261 to $300 compared to a base of about $4,250 for persons without pain. The value of lost productivity due to pain ranged from $299 to $335 billion. We found that the annual cost of pain was greater than the annual costs of heart disease ($309 billion), cancer ($243 billion), and diabetes ($188 billion). Our estimates are conservative because they do not include costs associated with pain for nursing home residents, children, military personnel, and persons who are incarcerated. Perspective: This study estimates that the national cost of pain ranges from $560 to $635 billion, larger than the cost of the nation's priority health conditions. Because of its economic toll on society, the nation should invest in research, education, and training to advocate the successful treatment, management, and prevention of pain.
Article
Neuroticism predisposes to anxiety disorders, but the precise pathogenic mechanism is unknown. The aim of this study was to examine whether people with high neuroticism scores use a lower criterion for detecting danger in the face of ambiguous stimuli, and avoid a greater number of ambiguous stimuli than people with low neuroticism scores. Participants high and low in neuroticism were administered a differential conditioning task, in which one conditioned stimulus (CS+; colored circle) was followed by an electric shock (unconditioned stimulus; UCS), whereas another stimulus (CS−; different colored circle) was not. After this acquisition phase, degraded colored circles on a continuum between CS+ and CS− were presented and could be avoided by the participants within a latency of 1 or 5 s. Results indicated that the high neuroticism group avoided more degraded stimuli than the low neuroticism group, but only at the 5 s latency trials. The absence of differences at the 1 s latency trials suggests the involvement of a strategic process. Apparently, when confronted with ambiguous threat signals, people high in neuroticism use a better safe than sorry strategy. By preventing disconfirmation of irrational fears, this strategy may be involved in the development and maintenance of anxiety disorders.
Article
Using a conditioned suppression task, we investigated simultaneous (XA−/A+) vs. sequential (X → A−/A+) Feature Negative (FN) discrimination learning in humans. We expected the simultaneous discrimination to result in X (or alternatively the XA configuration) becoming an inhibitor acting directly on the US, and the sequential discrimination in X becoming a negative occasion setter acting indirectly on the A–US link. After simultaneous FN training, X+ training completely abolished discriminative XA/A responding (Experiment 1), and X transferred inhibition to new targets B regardless of their training history (B+ or YB−/B+) (Experiment 2), suggesting X became a simple inhibitor. After sequential FN training, X showed the predicted selective transfer to a target B that also had been modulated (Y → B−/B+), not to a simple excitor (B+) (Experiment 4), but turning X into an excitor (X+) likewise disrupted discriminative X → A/A responding (Experiment 3). This suggests that X acquired a combination of modulatory and direct inhibitory properties, and that the joint contribution of both components is necessary for the suppression of the target-induced US activation.