Pavlovian-to-instrumental transfer in individuals with chronic pain.

Avoidance of pain has been argued to be key factor leading pain events to chronic disability. In this respect, research has focused on investigating the working mechanisms of avoidance's acquisition. Avoidance of painful stimuli has been traditionally studied using a combination of Pavlovian and Instrumental procedures. However, such approach seems to go against real-life scenarios where avoidance is commonly acquired more readily. Using a novel pain avoidance paradigm, we tested whether pain avoidance can be installed in absence of associations between a cue and pain omission, and whether such avoidance differs between pain patients and healthy controls. Participants first learned to avoid painful stimuli by pressing a grip bar. Then, they passively encountered pairings of one geometrical shape with pain and of another geometrical shape without pain. Lastly, participants encountered the geometrical shapes while being able to use the grip bar. Results showed that participants pressed the bar more vigorously when encountering the previously pain-related shape compared to the pain-unrelated shape. This effect did not seem to differ between pain patients and healthy control. Our study could inspire a new way in measuring avoidance in pain, possibly paving the way to better understanding how avoidance is installed in chronic pain.

Context reexposure to bolster contextual dependency of emotional episodic memory.

Contextual overgeneralization of emotional memory is a core aspect of anxiety disorders. Identifying methods to enhance contextual dependency of emotional memory is therefore of significant clinical interest. Animal research points to a promising approach: reexposure to the context in which fear is acquired reduces generalization to other contexts. However, the exact conditions for this effect are unknown, complicating translation to effective interventions. Most notably, exposure to a context that resembles-but is not identical to-the learning context may diminish contextual dependency of memory by integration of additional contextual cues. Here, we therefore assessed in a large-scale study (N = 180) whether context reexposure enhances contextual dependency of emotional episodic memory whereas exposure to a similar context impairs it. We also tested whether relatively strong memory retrieval during context (re)exposure amplifies these effects. We replicated prior research showing that correct recognition depends on context and contextual dependency is lower for emotional than neutral memories. However, exposure to the encoding context or a similar context did not affect contextual dependency of memory, and retrieval strength did not interact with such effects. Thorough insight into factors underlying the effects of context (re)exposure on contextual dependency seems key to eventually attain a memory recontextualization intervention.

Experimental Pain Picture System (EPPS): Development and Validation.

Pain-related pictures are useful for studying how individuals respond to pain-related stimulation. Such pictures can occasionally be found in databases for affective pictures. However, a validated database specifically for pain-related pictures is not available yet. In 2 experiments (N = 185 and 103, respectively), we developed and validated the Experimental Pain Pictures System (EPPS). In both experiments, negative valence, arousal, and painfulness ratings were compared between neutral-, sad-, and pain-related pictures. The pain-related pictures represented both deep and superficial somatic pain. Across the 2 experiments, pain-related pictures were judged as more negative, arousing, and painful than neutral pictures and more painful than sad pictures. The final EPPS contains 50 pictures of different painful events considered moderately to highly painful by participants. The EPPS is a valuable tool for studying pain-related responses, as it gives researchers a choice among many validated pictures depicting different types of pain, increasing the comparability between studies. PERSPECTIVE: This article presents the validation of the experimental pain pictures system, which consists of a set of pain-related pictures. The experimental pain pictures system is composed of pictures depicting different types of pain. Participants rated all the pictures as being negative, arousing, and painful.

The role of intolerance of uncertainty when solving the exploration-exploitation dilemma.

When making behavioral decisions, individuals need to balance between exploiting known options or exploring new ones. How individuals solve this exploration-exploitation dilemma (EED) is a key research question across psychology, leading to attempting to disentangle the cognitive mechanisms behind it. A potential predictive factor of performance in an EED is intolerance of uncertainty (IU), an individual difference factor referring to the extent to which uncertain situations are reported to be aversive. Here, we present the results of a series of exploratory analyses in which we tested the relationship between IU and performance in an EED task. For this, we compiled data from 3 experiments, in which participants received the opportunity to exploit different movements in order to avoid a painful stimulus and approach rewards. For decomposing performance in this task, we used different computational models previously employed in studies on the EED. Then, the parameters of the winning model were correlated with the scores of participants in the IU scale. Correlational and cluster analyses, within both frequentists and Bayesian frameworks, did not provide strong evidence for a relation between EED and IU, apart from the decay rate and the subscale "tendency to become paralyzed in the face of uncertainty". Given the theoretical relation between EED and IU, we propose research with different experimental paradigms.

Safety behaviors toward innocuous stimuli can maintain or increase threat beliefs.

Safety behaviors can prevent or minimize a feared outcome. However, in relatively safe situations, they may be less adaptive, presumably because people will misattribute safety to these behaviors. This research aimed to investigate whether safety behaviors in safe situations can lead to increased threat beliefs. In Study 1, we aimed to replicate a fear conditioning study (N = 68 students) in which the experimental, but not the control group, received the opportunity to perform safety behavior to an innocuous stimulus. From before to after the availability of the safety behavior, threat beliefs persisted in the experimental group, while they decreased in the control group. In Study 2, we examined whether threat beliefs had actually increased for some individuals in the experimental group, using a multi-dataset latent class analysis on data from Study 1 and two earlier studies (N = 213). Results showed that about a quarter of individuals who performed safety behavior toward the innocuous stimulus showed increased threat expectancy to this cue, while virtually nobody in the control group exhibited an increase. Taken together, safety behavior in relatively safe situations may have maladaptive effects as it generally maintains and sometimes even increases threat beliefs.

Multiverse analyses in fear conditioning research.

There is heterogeneity in and a lack of consensus on the preferred statistical analyses in light of a multitude of potentially equally justifiable approaches. Here, we introduce multiverse analysis for the field of experimental psychopathology research. We present a model multiverse approach tailored to fear conditioning research and, as a secondary aim, introduce the R package 'multifear' that allows to run all the models though a single line of code. Model specifications and data reduction approaches were identified through a systematic literature search. The heterogeneity of statistical models identified included Bayesian ANOVA and t-tests as well as frequentist ANOVA, t-test as well as mixed models with a variety of data reduction approaches. We illustrate the power of a multiverse analysis for fear conditioning data based on two pre-existing data sets with partial (data set 1) and 100% reinforcement rate (data set 2) by using CS discrimination in skin conductance responses (SCRs) during fear acquisition and extinction training as case examples. Both the effect size and the direction of effect was impacted by choice of the model and data reduction techniques. We anticipate that an increase in multiverse-type of studies will aid the development of formal theories through the accumulation of empirical evidence and ultimately aid clinical translation.

A meta-analysis of conditioned fear generalization in anxiety-related disorders.

Generalization of conditioned fear is adaptive in some situations but maladaptive when fear excessively generalizes to innocuous stimuli with incidental resemblance to a genuine threat cue. Recently, empirical interest in fear generalization as a transdiagnostic explanatory mechanism underlying anxiety-related disorders has accelerated. As there are now several studies of fear generalization across multiple types of anxiety-related disorders, the authors conducted a meta-analysis of studies reporting behavioral measures (subjective ratings and psychophysiological indices) of fear generalization in anxiety-related disorder vs. comparison groups. We conducted systematic searches of electronic databases (conducted from January-October 2020) for fear generalization studies involving anxiety-related disorder groups or subclinical analog groups. A total of 300 records were full-text screened and two unpublished datasets were obtained, yielding 16 studies reporting behavioral fear generalization measures. Random-effects meta-analytic models and meta-regressions were applied to the identified data. Fear generalization was significantly heightened in anxiety-related disorder participants (N = 439) relative to comparison participants (N = 428). We did not identify any significant clinical, sample, or methodological moderators. Heightened fear generalization is quantitatively supported as distinguishing anxiety-related disorder groups from comparison groups. Evidence suggests this effect is transdiagnostic, relatively robust to experimental or sample parameters, and that generalization paradigms are a well-supported framework for neurobehavioral investigations of learning and emotion in anxiety-related disorders. We discuss these findings in the context of prior fear conditioning meta-analyses, past neuroimaging investigations of fear generalization in anxiety-related disorders, and future directions and challenges for the field.

The exploration-exploitation dilemma in pain: an experimental investigation.

ABSTRACT: Daily life consists of a chain of decisions. Typically, individuals may choose to pursue what they already know (exploitation) or to search for other options (exploration). This exploration-exploitation dilemma is a topic of interest across multiple scientific fields. Here we propose that investigating how individuals solve this dilemma may improve our understanding of how individuals make behavioral decisions (eg, avoidance) when facing pain. To this end, we present the data of 3 experiments in which healthy individuals were given the opportunity to choose between 4 different movements, with each movement being associated with different probabilities of receiving a painful outcome only (experiment 1) or pain and/or a reward (experiment 2). We also investigated whether participants stuck to their decisions when the contingencies between each movement and the painful/rewarding outcome changed during the task (experiment 3). The key findings across all experiments are the following: First, after initial exploration, participants most often exploited the safest option. Second, participants weighted rewards more heavily than receiving pain. Finally, after receiving a painful outcome, participants were more inclined to explore than to exploit a rewarding movement. We argue that by focusing more on how individuals in pain solve the exploration-exploitation dilemma is helpful in understanding behavioral decision making in pain.

Postural freezing relates to startle potentiation in a human fear-conditioning paradigm.

Freezing to impending threat is a core defensive response. It has been studied primarily using fear conditioning in non-human animals, thwarting advances in translational human anxiety research that has used other indices, such as skin conductance responses. Here we examine postural freezing as a human conditioning index for translational anxiety research. We employed a mixed cued/contextual fear-conditioning paradigm where one context signals the occurrence of the US upon the presentation of the CS, and another context signals that the CS is not followed by the US. Critically, during the following generalization phase, the CS is presented in a third and novel context. We show that human freezing is highly sensitive to fear conditioning, generalizes to ambiguous contexts, and amplifies with threat imminence. Intriguingly, stronger parasympathetically driven freezing under threat, but not sympathetically mediated skin conductance, predicts subsequent startle magnitude. These results demonstrate that humans show fear-conditioned animal-like freezing responses, known to aid in active preparation for unexpected attack, and that freezing captures real-life anxiety expression. Conditioned freezing offers a promising new, non-invasive, and continuous, readout for human fear conditioning, paving the way for future translational studies into human fear and anxiety.

Does an unconditioned stimulus memory devaluation procedure decrease disgust memories and conditioned disgust? Results of two laboratory studies.

Research has demonstrated that disgust can be installed through classical conditioning by pairing neutral conditioned stimuli (CSs) with disgusting unconditioned stimuli (USs). Disgust has been argued to play an important role in maintaining fear-related disorders. This maintaining role may be explained by conditioned disgust being less sensitive to extinction (i.e., experiencing the CS in the absence of the US). Promising alternatives to extinction training are procedures that focus on the devaluation of US memory representations. In the current study, we investigated whether such devaluation procedures can be successful to counter conditioned disgust. We conducted two laboratory studies (N = 120 and N = 51) in which disgust was conditioned using audio-visual USs. Memory representations of the USs were devalued by having participants recall these USs while they performed a taxing eye-movement task or executed one of several control tasks. The results showed successful conditioned disgust acquisition. However, no strong evidence was obtained that an US memory devaluation procedure modulates disgust memory and diminishes conditioned disgust as indicated by subjective, behavioral, or psychophysiological measures. We discuss the relevance of our results for methodological improvements regarding US memory devaluation procedures and disgust conditioning.

Enhancing extinction with response prevention via imagery-based counterconditioning: Results on conditioned avoidance and distress.

BACKGROUND AND OBJECTIVES: Maladaptive avoidance is a core characteristic of anxiety-related disorders. Its reduction is often promoted using extinction with response prevention (ExRP) procedures, but these effects are often short-lived. Research has shown that pairing a feared stimulus with a stimulus of an incompatible valence (i.e., counterconditioning) may be effective in reducing fear. This laboratory study tested whether positive imagery during ExRP (i.e., imagery counterconditioning protocol) can also reduce avoidance. METHODS: In the counterconditioning procedure, participants imagined a positive sound. There were four phases. First, participants were presented with squares on a computer screen of which one (CS+) was paired with an aversive sound and another (CS-) was not. Second, they learned to avoid the negative sound in the presence of the CS+, via a key press. Third, they were assigned to either the Counterconditioning (that was asked to imagine a positive sound during ExRP) or No Counterconditioning group (standard ExRP). Finally, they performed a test phase that consisted of two parts: in the first part, avoidance responses were available for each CS and in the second part, these responses were prevented. RESULTS: The Counterconditioning intervention resulted in a short-lived reduction of distress associated with the CS+. However, groups did not differ in avoidance or distress during the test phases. LIMITATIONS: US-expectancy ratings were collected only at the end of the experiment. CONCLUSIONS: The results indicate that positive imagery during ExRP may be effective in reducing distress during the intervention. Explanations for the persistence of avoidance and fear are discussed.

Human fear conditioning is moderated by stimulus contingency instructions.

Recent research findings indicate that human fear conditioning is affected by instructions, particularly those concerning the contingency between the conditioned stimulus (CS) and the unconditioned stimulus (US). However, whether or not such instructions were provided to participants often remains unsaid in fear conditioning studies. In the current study (N = 102), we investigated whether conditioned fear acquisition depends on CS-US contingency instructions. Participants were randomly assigned to one of three groups. The first group was instructed about the precise CS-US contingency before conditioning. The second group was instructed to discover the CS-US contingency. The third group did not receive any contingency instructions. We found facilitated fear acquisition (using skin conductance and startle) and increased contingency awareness in the first and second group compared to the third group. Furthermore, contingency reversal instructions immediately reversed conditioned responses. Based on these results, we advise to systematically report the contingency instructions used in fear conditioning research.

From adaptive to maladaptive fear: Heterogeneity in threat and safety learning across response systems in a representative sample.

Individual differences in fear learning are a crucial prerequisite for the translational value of the fear-conditioning model. In a representative sample (N = 936), we used latent class growth models to detect individual differences in associative fear learning. For a series of subsequent test phases varying in ambiguity (i.e., acquisition, extinction, generalization, reinstatement, and re-extinction), conditioned responding was assessed on three response domains (i.e., subjective distress, startle responding, and skin conductance). We also associated fear learning across the different test phases and response domains with selected personality traits related to risk and resilience for anxiety, namely Harm Avoidance, Stress Reaction, and Wellbeing (MPQ; Tellegen and Waller, 2008). Heterogeneity in fear learning was evident, with fit indices suggesting subgroups for each outcome measure. Identified subgroups showed adaptive, maladaptive, or limited-responding patterns. For subjective distress, fear and safety learning was more maladaptive in the subgroups high on Harm Avoidance, while more adaptive learning was observed in subgroups with medium Harm Avoidance and the limited- or non-responders were lowest in Harm Avoidance. Distress subgroups did not differ in Stress Reaction or Wellbeing. Startle and SCR subgroups did not differ on selected personality traits. The heterogeneity in fear-learning patterns resembled risk and resilient anxiety development observed in real life, which supports the associative fear-learning paradigm as a useful translational model for pathological fear development.

Decomposing conditioned avoidance performance with computational models.

Avoidance towards innocuous stimuli is a key characteristic across anxiety-related disorders and chronic pain. Insights into the relevant learning processes of avoidance are often gained via laboratory procedures, where individuals learn to avoid stimuli or movements that have been previously associated with an aversive stimulus. Typically, statistical analyses of data gathered with conditioned avoidance procedures include frequency data, for example, the number of times a participant has avoided an aversive stimulus. Here, we argue that further insights into the underlying processes of avoidance behavior could be unraveled using computational models of behavior. We then demonstrate how computational models could be used by reanalysing a previously published avoidance data set and interpreting the key findings. We conclude our article by listing some challenges in the direct application of computational modeling to avoidance data sets.

Reduction of conditioned avoidance via contingency reversal.

There is an increased interest in how excessive avoidance can diminish. Avoidance reduction is typically tested by using Extinction with Response Prevention (ExRP) protocols, where feared stimuli are presented without any aversive outcome while avoidance is prevented. These effects, however, often do not persist. Here, we tested whether pairing an avoidance response with the presence of an aversive event would reduce avoidance more than ExRP. Participants (N = 58) first saw a picture of a square (A) being paired with a shock whereas another picture of a square (B) not being paired with a shock. Then, they learned to press a button during the presentation of A to avoid the shock. Afterwards, the ExRP group saw unreinforced presentations of A and B without being able to press the avoidance button, whereas the Contingency Reversal group (ConR) received a shock whenever they pressed the button in presence of A. In the test phase, participants saw unreinforced presentations of A and B. Results showed that after successful acquisition of fear and avoidance, in the test phase the ConR group avoided A less often than did the ExRP group. Research on contingency reversal could prove helpful for developing avoidance reduction protocols.

A review on mental imagery in fear conditioning research 100 years since the 'Little Albert' study.

Since the seminal 'Little Albert' study by Watson and Rayner (1920), fear conditioning has become one of the most commonly used paradigms for studying the etiology of anxiety-related disorders. In a fear conditioning procedure, a (neutral) conditioned stimulus (CS) is paired with an aversive unconditioned stimulus (US), resulting in fear-related conditioned responses (CRs) to the CS. Whereas fear conditioning research initially focused on observable elements in the environment (i.e., CSs, USs, and their contingency) and their effects (i.e., CRs), subsequent research indicated that attention should also be given to unobservable mental events (e.g., intrusive memories of aversive outcomes) to more fully account for the symptomatology of anxiety disorders. In this paper, we review the research relating to four major research questions on the relationship between mental imagery and fear conditioning: (1) Can mental imagery substitute for actual stimulus administration? (2) Can mental imagery inflate CRs? (3) Can fear conditioning result in the installment of mental images as CRs (i.e., intrusions)? (4) Can mental imagery-based interventions reduce CRs? For all these research questions, tentative confirmatory evidence has been found and these findings corroborate contemporary conditioning theories. Nonetheless, we point to several open questions and methodological issues that require further research.

Preregistration of Analyses of Preexisting Data.

The preregistration of a study's hypotheses, methods, and data-analyses steps is becoming a popular psychological research practice. To date, most of the discussion on study preregistration has focused on the preregistration of studies that include the collection of original data. However, much of the research in psychology relies on the (re-)analysis of preexisting data. Importantly, this type of studies is different from original studies as researchers cannot change major aspects of the study (e.g., experimental manipulations, sample size). Here, we provide arguments as to why it is useful to preregister analyses of preexisting data, discuss practical considerations, consider potential concerns, and introduce a preregistration template tailored for studies focused on the analyses of preexisting data. We argue that the preregistration of hypotheses and data-analyses for analyses of preexisting data is an important step towards more transparent psychological research.