Shock Expectancy Ratings Research Articles

Sleep deprivation increases the generalization of perceptual and concept-based fear: An fNIRS study

Insufficient sleep can initiate or exacerbate anxiety by triggering excessive fear generalization. In this study, a de novo paradigm was developed and used to examine the neural mechanisms governing the effects of sleep deprivation on processing perceptual and concept-based fear generalizations. A between-subject design was adopted, wherein a control group (who had a typical night's sleep) and a one-night sleep deprivation group completed a fear acquisition task at 9:00 PM on the first day and underwent a generalization test the following morning at 7:00 AM. In the fear acquisition task, navy blue and olive green were used as perceptual cues (P+ and P−, respectively), while animals and furniture items were used as conceptual cues (C+ and C−, respectively). Generalization was tested for four novel generalized categories (C+P+, C+P−, C−P+, and C−P−). Shock expectancy ratings, skin conductance responses, and functional near-infrared spectroscopy were recorded during the fear acquisition and generalization processes. Compared with the group who had a typical night's sleep, the sleep deprived group showed higher shock expectancy ratings (especially for P+ and C−), increased oxygenated hemoglobin in the dorsolateral prefrontal cortex, and increased activation in the triangular inferior frontal gyrus during the generalization test. These findings suggest that sleep deprivation increases the generalization of threat memories, thus providing insights into the overgeneralization characteristics of anxiety and fear-related disorders.

Individual patterns of visual exploration predict the extent of fear generalization in humans.

Generalization of fear is considered an important mechanism contributing to the etiology and maintenance of anxiety disorders. Although previous studies have identified the importance of stimulus discrimination for fear generalization, it is still unclear to what degree overt attention to relevant stimulus features might mediate its magnitude. To test the prediction that visual preferences for distinguishing stimulus aspects are associated with reduced fear generalization, we developed a set of facial stimuli that was meticulously manipulated such that pairs of faces could either be distinguished by looking into the eyes or into the region around mouth and nose, respectively. These pairs were then employed as CS + and CS- in a differential fear conditioning paradigm followed by a generalization test with morphs in steps of 20%. Shock expectancy ratings indicated a moderately curved fear generalization gradient that is typical for healthy samples, but its shape was altered depending on individual attentional deployment: Particpants who dwelled on the distinguishing facial features faster and for longer periods of time exhibited less fear generalization. Although both pupil and heart rate responses also showed a generalization gradient, with pupil diameter and heart rate deceleration increasing as a function of threat, these responses were not significantly related to visual exploration. In total, the current results indicate that the extent of explicit fear generalization depends on individual patterns of attentional deployment. Future studies evaluating the efficacy of perceptual trainings that aim to augment stimulus discriminability in order to reduce (over)generalization seem desirable. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Impact of observational and direct learning on fear conditioning and generalization in humans

Humans gain knowledge about threats not only from their own experiences but also from observing others' behavior. A neutral stimulus is associated with a threat stimulus for several times and the neutral stimulus will evoke fear responses, which is known as fear conditioning. When encountering a new event that is similar to one previously associated with a threat, one may feel afraid and produce fear responses. This is called fear generalization. Previous studies have mostly focused on fear conditioning and generalization based on direct learning, but few have explored how observational fear learning affects fear conditioning and generalization. To the best of our knowledge, no previous study has focused on the neural correlations of fear conditioning and generalization based on observational learning. In the present study, 58 participants performed a differential conditioning paradigm in which they learned the associations between neutral cues (i.e., geometric figures) and threat stimuli (i.e., electric shock). The learning occurred on their own (i.e., direct learning) and by observing other participant's responses (i.e., observational learning); the study used a within-subjects design. After each learning condition, a fear generalization paradigm was conducted by each participant independently while their behavioral responses (i.e., expectation of a shock) and electroencephalography (EEG) recordings or responses were recorded. The shock expectancy ratings showed that observational learning, compared to direct learning, reduced the differentiation between the conditioned threatening stimuli and safety stimuli and the increased shock expectancy to the generalization stimuli. The EEG indicated that in fear learning, threatening conditioned stimuli in observational and direct learning increased early discrimination (P1) and late motivated attention (late positive potential [LPP]), compared with safety conditioned stimuli. In fear generalization, early discrimination, late motivated attention, and orienting attention (alpha-event-related desynchronization [alpha-ERD]) to generalization stimuli were reduced in the observational learning condition. These findings suggest that compared to direct learning, observational learning reduces differential fear learning and increases the generalization of fear, and this might be associated with reduced discrimination and attentional function related to generalization stimuli.

Stimulus diversity increases category-based fear generalization and the effect of intolerance of uncertainty

Fear generalization refers to conditioned fear responses extending to related stimuli and fear overgeneralization is a key feature of pathological anxiety. Along with perception similarity, conceptual relations affect fear generalization. We investigated whether stimulus diversity–an important principle of category-based induction–influences fear generalization. Induction studies have shown that generalization from a premise involving diverse instances is stronger than that from non-diverse instances. We adopted this framework for fear learning and established two groups. The diverse group developed fear in response to diverse instances from one category, while the non-diverse group acquired fear of non-diverse instances from the same category. An effect of stimulus diversity was observed in shock-expectancy ratings, with the diverse group displaying higher fear generalization than the non-diverse group. We also tested whether intolerance of uncertainty (IU) might affect the difference in fear generalization between the two conditions. Individuals with higher IU showed reduced difference in fear generalization between two conditions, mainly driven by heightened fear generalization to novel stimulus with ambiguous threat levels in the non-diverse condition. This study helps illustrate the mechanisms behind differential category-based fear generalization and provides a potential explanation for why higher IU individuals may develop anxiety disorders following trauma.

Breakfast or bakery? The role of categorical ambiguity in overgeneralization of learned fear in trait anxiety.

Pavlovian conditioning studies have shown that humans can generalize conditioned fear to novel stimuli that are categorically related to the threat cue, despite perceptual dissimilarities. The current work examined the role of trait anxiety in the generalization of fear to categorically related objects. Items from 1 category, breakfast or bakery, were paired with shock whereas items from the other category were not. Participants were then tested on ambiguous cross-classified items-those that fitted in both the threat and safe categories. No trait anxiety effect was found in generalization to novel stimuli that clearly belonged to either the threat or the safe category in either shock expectancy ratings or skin conductance. In contrast, trait anxious individuals showed a bias toward higher threat appraisal to the ambiguous cross-classified stimuli. However, this pattern was not due to trait anxious individuals being more likely to perceive ambiguous items as belonging to the threat category. Instead they appear to display a bias toward overestimation of threat when the threat level is ambiguous. The current findings indicate that threat ambiguity modulates the effect of trait anxiety on categorical fear generalization. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Attentive immobility in the face of inevitable distal threat-Startle potentiation and fear bradycardia as an index of emotion and attention.

During fear conditioning, a cue (CS) signals an inevitable distal threat (US) and evokes a conditioned response that can be described as attentive immobility (freezing). The organism remains motionless and monitors the source of danger while startle responses are potentiated, indicating a state of defensive hypervigilance. Although in animals vagally mediated fear bradycardia is also reliably observed under such circumstances, results are mixed in human fear conditioning. Using a single-cue fear conditioning and extinction protocol, we tested cardiac reactivity and startle potentiation indexing low-level defensive strategies in a fear-conditioned (n=40; paired presentations of CS and US) compared with a non-conditioned control group (n=40; unpaired presentations of CS and US). Additionally, we assessed shock expectancy ratings on a trial-by-trial basis indexing declarative knowledge of the previous contingencies. Half of each group underwent extinction under sham or active transcutaneous vagus nerve stimulation (tVNS), serving as additional proof of concept. We found stronger cardiac deceleration during CS presentation in the fear learning relative to the control group. This learned fear bradycardia was positively correlated with conditioned startle potentiation but not with declarative knowledge of CS-US contingencies. TVNS abolished differences in heart rate changes between both groups and removed the significant correlation between late cardiac deceleration and startle potentiation in the fear learning group. Results suggest, fear-conditioned cues evoke attentive immobility in humans, characterized by cardiac deceleration and startle potentiation. Such defensive response pattern is elicited by cues predicting inevitable distal threat and resembles conditioned fear responses observed in rodents.

Latent class growth analyses reveal overrepresentation of dysfunctional fear conditioning trajectories in patients with anxiety-related disorders compared to controls

Recent meta-analyses indicated differences in fear acquisition and extinction between patients with anxiety-related disorders and comparison subjects. However, these effects are small and may hold for only a subsample of patients. To investigate individual trajectories in fear acquisition and extinction across patients with anxiety-related disorders (N = 104; before treatment) and comparison subjects (N = 93), data from a previous study (Duits et al., 2017) were re-analyzed using data-driven latent class growth analyses. In this explorative study, subjective fear ratings, shock expectancy ratings and startle responses were used as outcome measures. Fear and expectancy ratings, but not startle data, yielded distinct fear conditioning trajectories across participants. Patients were, compared to controls, overrepresented in two distinct dysfunctional fear conditioning trajectories: impaired safety learning and poor fear extinction to danger cues. The profiling of individual patterns allowed to determine that whereas a subset of patients showed trajectories of dysfunctional fear conditioning, a significant proportion of patients (≥50 %) did not. The strength of trajectory analyses as opposed to group analyses is that it allows the identification of individuals with dysfunctional fear conditioning. Results suggested that dysfunctional fear learning may also be associated with poor treatment outcome, but further research in larger samples is needed to address this question.

Beyond arousal: Prediction error related to aversive events promotes episodic memory formation.

Stimuli encoded shortly before an aversive event are typically well remembered. Traditionally, this emotional memory enhancement has been attributed to beneficial effects of physiological arousal on memory formation. Here, we proposed an additional mechanism and tested whether memory formation is driven by the unpredictable nature of aversive events (i.e., aversive prediction errors). In a combined Pavlovian fear conditioning and incidental memory paradigm, participants saw initially neutral pictures from 2 distinct categories, 1 of which was associated with a risk to receive an electric shock. During encoding, we measured both physiological arousal and explicit prediction errors to explain memory differences in a surprise recognition test that followed approximately 24 hr later. In a first experiment, we show that physiological arousal, expressed as outcome-related skin conductance responses, was associated with improved recognition memory, corroborating arousal-based models. Critically, unsigned binary prediction errors derived from explicit shock expectancy ratings in each trial were also linked to enhanced recognition and model fits showed that the impact of prediction errors on memory was dissociable from the impact of arousal. In a second experiment, we replicated and extended the findings of the first experiment by demonstrating that the memory-promoting effect of prediction errors remained even after controlling for arousal. The present data point to prediction error-related learning as a cognitive mechanism that contributes to the emotional enhancement of memory, above and beyond the well-established effects of arousal in emotional memory formation. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Effect of d-cycloserine on fear extinction training in adults with social anxiety disorder.

Preclinical and clinical data have shown that D-cycloserine (DCS), a partial agonist at the N-methyl-d-aspartate receptor complex, augments the retention of fear extinction in animals and the therapeutic learning from exposure therapy in humans. However, studies with non-clinical human samples in de novo fear conditioning paradigms have demonstrated minimal to no benefit of DCS. The aim of this study was to evaluate the effects of DCS on the retention of extinction learning following de novo fear conditioning in a clinical sample. Eighty-one patients with social anxiety disorder were recruited and underwent a previously validated de novo fear conditioning and extinction paradigm over the course of three days. Of those, only 43 (53%) provided analyzable data. During conditioning on Day 1, participants viewed images of differently colored lamps, two of which were followed by with electric shock (CS+) and a third which was not (CS-). On Day 2, participants were randomly assigned to receive either 50 mg DCS or placebo, administered in a double-blind manner 1 hour prior to extinction training with a single CS+ in a distinct context. Day 3 consisted of tests of extinction recall and renewal. The primary outcome was skin conductance response to conditioned stimuli, and shock expectancy ratings were examined as a secondary outcome. Results showed greater skin conductance and expectancy ratings in response to the CS+ compared to CS- at the end of conditioning. As expected, this difference was no longer present at the end of extinction training, but returned at early recall and renewal phases on Day 3, showing evidence of return of fear. In contrast to hypotheses, DCS had no moderating influence on skin conductance response or expectancy of shock during recall or renewal phases. We did not find evidence of an effect of DCS on the retention of extinction learning in humans in this fear conditioning and extinction paradigm.

Interpretation bias in the face of pain: a discriminatory fear conditioning approach.

Background and aims Interpreting pain- and illness-related stimuli as health-threatening is common among chronic pain patients but also occurs in the general population. As interpretation bias (IB) may affect pain perception and might even play part in the development and maintenance of chronic pain, it is important to improve our understanding of this concept. Several studies suggest an association between IB and pain-related anxiety. However, those studies often rely on verbal and pictorial IB tasks that do not entail a threat of actual pain, therefore lacking personal relevance for healthy participants. The current study investigated whether healthy individuals show an IB towards ambiguous health-related stimuli in a context of actual pain threat, and explored whether this bias is associated to pain anxiety constructs. Methods Thirty-six healthy participants were conditioned to expect painful electrocutaneous shocks (unconditioned stimulus - US) after health-threat words (CS+) but not after neutral (non-health-threat) words (CS-) in order to establish fear of pain. Subsequently, they completed a verbal interpretation task that contained new CS+ and CS- stimuli as well as ambiguous non-reinforced health-threat and non-health-threat words. IB was assessed through shock expectancy ratings and startle responses to ambiguous and evident health threatening or neutral word stimuli. Pain-related anxiety was measured with validated questionnaires. Results The results show a general IB towards ambiguous health-related words on pain expectancies but not on startle response. An exploratory analysis suggests that this effect exists irrespective of pain-related anxiety levels which however may be due to a lack of power. Conclusion We present a novel experimental paradigm employing actual health threat that captures IB towards health-related stimuli in healthy individuals. Taken together, results provide evidence for the further consideration of IB as a latent vulnerability factor in the onset and maintenance of pain chronicity. In contrast to previous studies employing a safe, pain-free context, we found that healthy participants show an IB towards ambiguous health-related stimuli, when confronted with pain threat. Implications Like chronic pain patients, healthy individuals display an IB towards health-threat stimuli when these stimuli become personally relevant by carrying information about pending health threat. Therefore, the presented paradigm could be valuable for pain-related cognitive bias research in healthy participants as it may have a higher ecological validity than previous study designs. Future studies will have to elucidate the influence of anxiety constructs on IB in larger samples.

Rule-based processes in generalisation and peak shift in human fear conditioning.

Two experiments explored the role of verbalisable rules in generalisation of human differential fear conditioning with electric shock as the aversive stimulus. Two circles of different sizes served as conditioned stimuli (CS+ and CS-), before testing with a range of circle sizes. In Experiment 1, shock expectancy ratings followed a peak-shifted unimodal gradient, with maximum ratings at a test value further along the dimension from CS+ in the opposite direction to CS-. However, differentiable gradients were observed when participants were divided on the basis of the rules they reported using during the task (linear and similarity). Experiment 2 was designed to counter the contradictory feedback arising from extinction testing by removing the shock electrodes during the test phase. A more linear overall gradient was observed, and sub-groups defined by self-reported rules showed distinct gradients that were congruent with their rules. These results indicate that rule-based processes are influential in generalisation of conditioned fear along simple stimulus dimensions, and may help explain generalisation phenomena that have traditionally been attributed to automatic, similarity-based processes.

Linked networks for learning and expressing location-specific threat

Learning locations of danger within our environment is a vital adaptive ability whose neural bases are only partially understood. We examined fMRI brain activity while participants navigated a virtual environment in which flowers appeared and were "picked." Picking flowers in the danger zone (one-half of the environment) predicted an electric shock to the wrist (or "bee sting"); flowers in the safe zone never predicted shock; and household objects served as controls for neutral spatial memory. Participants demonstrated learning with shock expectancy ratings and skin conductance increases for flowers in the danger zone. Patterns of brain activity shifted between overlapping networks during different task stages. Learning about environmental threats, during flower approach in either zone, engaged the anterior hippocampus, amygdala, and ventromedial prefrontal cortex (vmPFC), with vmPFC-hippocampal functional connectivity increasing with experience. Threat appraisal, during approach in the danger zone, engaged the insula and dorsal anterior cingulate (dACC), with insula-hippocampal functional connectivity. During imminent threat, after picking a flower, this pattern was supplemented by activity in periaqueductal gray (PAG), insula-dACC coupling, and posterior hippocampal activity that increased with experience. We interpret these patterns in terms of multiple representations of spatial context (anterior hippocampus); specific locations (posterior hippocampus); stimuli (amygdala); value (vmPFC); threat, both visceral (insula) and cognitive (dACC); and defensive behaviors (PAG), interacting in different combinations to perform the functions required at each task stage. Our findings illuminate how we learn about location-specific threats and suggest how they might break down into overgeneralization or hypervigilance in anxiety disorders.

Rule-based generalisation in single-cue and differential fear conditioning in humans

Fear generalisation refers to the spread of conditioned fear to stimuli similar but distinct from the original conditioned stimulus. In this study, participants were presented with repeated pairings of a conditioned stimulus with a shock, in either a single-cue or differential conditioning paradigm. Generalisation of fear was then tested by presenting stimuli that were novel, but similar to the conditioned stimulus along a spatial stimulus dimension. Dependent measures were online shock expectancy ratings and skin conductance level. A diverse range of generalisation gradients was observed, and the shape of the gradients for both expectancy ratings and skin conductance responses corresponded with participants’ verbally reported rules. The findings point to an important role for cognitively controlled processes in human fear generalisation, and provide support for a single-system learning model. They also highlight the potential importance of cognitive reappraisal in clinical treatments for over-generalised fear.

Partial reinforcement of avoidance and resistance to extinction in humans

In anxiety, maladaptive avoidance behavior provides for near-perfect controllability of potential threat. There has been little laboratory-based treatment research conducted on controllability as a contributing factor in the transition from adaptive to maladaptive avoidance. Here, we investigated for the first time whether partial reinforcement rate, or the reliability of avoidance at controlling or preventing contact with an aversive event, influences subsequent extinction of avoidance in humans. Five groups of participants were exposed to different partial reinforcement rates where avoidance cancelled upcoming shock on 100%, 75%, 50%, 25% or 0% of trials. During extinction, all shocks were withheld. Avoidance behavior, online shock expectancy ratings and skin conductance responses (SCRs) were measured throughout. We found that avoidance was a function of relative controllability: higher reinforcement rate groups engaged in significantly more extinction-resistant avoidance than lower reinforcement groups, and shock expectancy was inversely related with reinforcement rate during avoidance acquisition. Partial reinforcement effects were not evident in SCRs. Overall, the current study highlights the clinical relevance of laboratory-based treatment research on partial reinforcement or controllability effects on extinction of avoidance.

Higher threat avoidance costs reduce avoidance behaviour which in turn promotes fear extinction in humans

Theoretical models specifying the underlying mechanisms of the development and maintenance of anxiety and related disorders state that fear responses acquired through classical Pavlovian conditioning are maintained by repeated avoidance behaviour; thus, it is assumed that avoidance prevents fear extinction. The present study investigated behavioural avoidance decisions as a function of avoidance costs in a naturalistic fear conditioning paradigm. Ecologically valid avoidance costs - manipulated between participant groups - were represented via time-delays during a detour in a gamified computer task. After differential acquisitions of shock-expectancy to a predictive conditioned stimulus (CS+), participants underwent extinction where they could either take a risky shortcut, while anticipating shock signaled by the CS+, or choose a costly avoidance option (lengthy detour); thus, they were faced with an approach-avoidance conflict. Groups with higher avoidance costs (longer detours) showed lower proportions of avoiders. Avoiders gave heightened shock-expectancy ratings post-extinction, demonstrating ‘protecting from extinction’, i.e. failure to extinguish. Moreover, there was an indirect effect of avoidance costs on protection from extinction through avoidance behaviour. No moderating role of trait-anxiety was found. Theoretical implications of avoidance behaviour are discussed, considering the involvement of instrumental learning in the maintenance of fear responses.

One-trial overshadowing: Evidence for fast specific fear learning in humans

Adaptive defensive actions necessitate a fear learning system that is both fast and specific. Fast learning serves to minimize the number of threat confrontations, while specific learning ensures that the acquired fears are tied to threat-relevant cues only. In Pavlovian fear conditioning, fear acquisition is typically studied via repetitive pairings of a single cue with an aversive experience, which is not optimal for the examination of fast specific fear learning. In this study, we adopted the one-trial overshadowing procedure from basic learning research, in which a combination of two visual cues is presented once and paired with an aversive electrical stimulation. Using on-line shock expectancy ratings, skin conductance reactivity and startle reflex modulation as indices of fear learning, we found evidence of strong fear after a single conditioning trial (fast learning) as well as attenuated fear responding when only half of the trained stimulus combination was presented (specific learning). Moreover, specificity of fear responding tended to correlate with levels of state and trait anxiety. These results suggest that one-trial overshadowing can be used as a model to study fast specific fear learning in humans and individual differences therein.

Estradiol is associated with altered cognitive and physiological responses during fear conditioning and extinction in healthy and spider phobic women.

The first-line psychological treatment for anxiety disorders is exposure therapy, which can be modeled in the laboratory using fear extinction. In healthy women, estradiol levels predict return of fear following extinction, whereas low levels are associated with greater return of fear. Investigating whether estradiol is similarly associated with extinction in clinically anxious women may provide insight to mechanisms underlying symptom relapse following exposure therapy. In the present study, women with spider phobia and healthy women participated in a 2-day fear conditioning and extinction procedure during a period of high or low estradiol levels. Skin conductance responses, shock expectancy, and valence ratings were measured throughout. Women exhibited comparable decreases in physiological arousal from conditioning to the end of extinction training on Day 1. However, compared to women with high estradiol, and irrespective of clinical status, women with low estradiol exhibited significant return of physiological arousal at extinction recall on Day 2, despite accurate ratings regarding the likelihood of shock. Low estradiol women also reported heightened threat expectancy and physiological responding during presentation of safety cues. These results may point to novel means of enhancing exposure therapy in women by timing treatment delivery during periods of higher estradiol levels. (PsycINFO Database Record

Fear generalization in humans: Impact of feature learning on conditioning and extinction

Little is known about the role of discrete stimulus features in the regulation of fear. This study examined the effects of feature learning on the acquisition and extinction of fear conditioning. Human participants were fear conditioned to a yellow triangle (CS+) using an electrical shock. We manipulated feature learning through differential conditioning. The nonconditioned control stimulus (CS−) was a red triangle in one group (Color-Relevant), but a yellow circle in the other group (Shape-Relevant). Next, two generalization stimuli were tested that shared the shape- or color-feature with the CS+ (a blue triangle and a yellow square). Online shock-expectancy ratings and skin conductance responding showed that the CS− determined the pattern of fear generalization: the same-color stimulus elicited more fear in Group Color-Relevant, versus the same-shape stimulus in group Shape-Relevant. Furthermore, extinguishing these two generalization stimuli had no detectable effect on fear of the CS+. These results show that fear generalization is influenced by feature learning through differential conditioning, and that exposures to different features of a stimulus are not sufficient to extinguish fear of that stimulus as a whole.

Impaired fear inhibition learning predicts the persistence of symptoms of posttraumatic stress disorder (PTSD)

Recent cross-sectional studies have shown that the inability to suppress fear under safe conditions is a key problem in people with posttraumatic stress disorder (PTSD). The current longitudinal study examined whether individual differences in fear inhibition predict the persistence of PTSD symptoms. Approximately 2 months after deployment to Afghanistan, 144 trauma-exposed Dutch soldiers were administered a conditional discrimination task (AX+/BX−). In this paradigm, A, B, and X are neutral stimuli. X combined with A is paired with a shock (AX+ trials); X combined with B is not (BX− trials). Fear inhibition was measured (AB trials). Startle electromyogram responses and shock expectancy ratings were recorded. PTSD symptoms were measured at 2 months and at 9 months after deployment.Results showed that greater startle responses during AB trials in individuals who discriminated between danger (AX+) and safety (BX−) during conditioning, predicted higher PTSD symptoms at 2 months and 9 months post-deployment. The predictive effect at 9 months remained significant after controlling for critical incidents during previous deployments and PTSD symptoms at 2 months. Responses to AX+ or BX− trials, or discrimination learning (AX+ minus BX−) did not predict PTSD symptoms. It is concluded that impaired fear inhibition learning seems to be involved in the persistence of PTSD symptoms.

Increasing the Selectivity of Threat through Post-Training Instructions: Identifying One Stimulus as Source of Danger Reduces the Threat Value of Surrounding Stimuli

The present study aimed to investigate whether instructional threat information can be used to remediate overgeneral threat appraisal. We investigated whether identifying one specific stimulus as cause of danger might reduce threat value of other stimuli that were present during an aversive conditioning event. Participants were shown two neutral stimuli, followed by an aversive shock. After the training phase, instructions informed the participants that one of the two stimuli was causative for the occurrence of the shock. Threat appraisal of the stimuli was measured through shock-expectancy ratings and skin conductance. Results demonstrate that identifying one stimulus as cause of shock successfully reduced shock-expectancy to the other stimulus that preceded the aversive shock event. The study suggests that singling out one stimulus as cause of danger decreases the threat value of other stimuli that were present during an aversive conditioning event, which makes it a potentially interesting strategy for the treatment of clinical anxiety.