US Expectancy Research Articles

Sometimes I feel the fear of uncertainty: How intolerance of uncertainty and trait anxiety impact fear acquisition, extinction and the return of fear

It is hypothesized that the ability to discriminate between threat and safety is impaired in individuals with high dispositional negativity, resulting in maladaptive behavior. A large body of research investigated differential learning during fear conditioning and extinction protocols depending on individual differences in intolerance of uncertainty (IU) and trait anxiety (TA), two closely-related dimensions of dispositional negativity, with heterogenous results. These might be due to varying degrees of induced threat/safety uncertainty. Here, we compared two groups with high vs. low IU/TA during periods of low (instructed fear acquisition) and high levels of uncertainty (delayed non-instructed extinction training and reinstatement). Dependent variables comprised subjective (US expectancy, valence, arousal), psychophysiological (skin conductance response, SCR, and startle blink), and neural (fMRI BOLD) measures of threat responding. During fear acquisition, we found strong threat/safety discrimination for both groups. During early extinction (high uncertainty), the low IU/TA group showed an increased physiological response to the safety signal, resulting in a lack of CS discrimination. In contrast, the high IU/TA group showed strong initial threat/safety discrimination in physiology, lacking discriminative learning on startle, and reduced neural activation in regions linked to threat/safety processing throughout extinction training indicating sustained but non-adaptive and rigid responding. Similar neural patterns were found after the reinstatement test. Taken together, we provide evidence that high dispositional negativity, as indicated here by IU and TA, is associated with greater responding to threat cues during the beginning of delayed extinction, and, thus, demonstrates altered learning patterns under changing environments.

Smokers show increased fear responses towards safety signals during fear generalization, independent from acute smoking

Smoking is highly prevalent among patients with anxiety disorders. Previous studies suggest that smokers show altered fear learning as compared to non-smokers. To test the effect of acute smoking on fear learning and generalization, we conducted a fear learning experiment online. 202 healthy subjects learned to differentiate a danger and a safe cue on day 1 and were tested for generalization of threat responses 24 h later. To see if the timing of smoking impacts fear learning, we formed three smoker groups with manipulations of acute smoking and withdrawal at different time-points (each group: n = 46) and one non-smoker control group (n = 64). Smoking manipulations contained a 6 h withdrawal after fear learning, smoking directly before or after fear learning. We found no group differences between smoker manipulation groups for fear learning or generalization. However, we found differences in fear generalization between smokers and non-smokers. Smokers showed increased fear ratings towards the stimulus that has been learned as safe and higher US expectancy to stimuli similar to the safe stimulus, when compared to non-smokers. Smoking might constitute a risk factor for impaired discrimination between danger and safety and smoking restrictions could be an effective way to reduce the risks of development or maintenance of anxiety disorders.

Fear reacquisition and symptoms of combat-related PTSD: Specificity and preliminary examination of the influence of the 5-HT3A receptor gene

Several studies have examined the acquisition and extinction of fear in PTSD in the context of Pavlovian conditioning. However, research examining reconditioning of fear following extinction, a form of post-extinction re-emergence of conditioned behavior is limited. Although the 5-HT3A receptor gene polymorphism has been linked to trauma responses, its influence on the re-emergence of conditioned fear among those exposed to trauma remain unclear. In the present study, combat-exposed veterans (N = 114) completed a differential fear conditioning task in which one colored rectangle (CS+) predicted a loud scream (US), whereas a different colored rectangle (CS-) predicted no US. Acquisition, extinction, and post-extinction reconditioning effects indexed by conditioned anxiety, US expectancy, and skin conductance response were examined. Associations with allelic variation in the serotonin 5-HT3 gene, HTR3A (rs1062613) were also examined. Participants rated the CS+ as significantly more anxiety inducing and associated with greater US expectancy than the CS- during acquisition. The CS+ also elicited a stronger skin conductance response than the CS- during acquisition. A significant decrease in anxiety and US expectancy in response to the CS+ was observed after extinction and a re-emergence of conditioned responses to the CS+ was observed during reacquisition. Although a diagnosis of PTSD was characterized by greater anxiety to the CS + but not the CS- during acquisition and extinction, those with and without a PTSD diagnosis did not differ in the reacquisition of fear following extinction. Subsequent preliminary analysis did show that increased posttraumatic symptoms and cognitions were associated with increased US expectancy at reacquisition for the CS+ and CS- among CC carriers but not among T carriers of HTR3A (rs1062613). These findings suggest that posttraumatic symptoms among trauma exposed veterans with the CC polymorphism of the HTR3A gene may be associated with stronger reconditioning of fear following extinction.

Verbalisation of attention regulation strategies and background music enhance extinction learning and retention

Relapse and return of fear are common following exposure-based treatments which aim to decrease anxiety by reducing danger expectancies and negative stimulus evaluations. Using Pavlovian conditioning and extinction procedures, recent studies found that verbalising catchphrases to prompt attention to, and memory of, stimulus contingencies during extinction prevented US expectancy generalisation to safe stimuli and reduced anxiety ratings. Verbalizations did not improve negative evaluations of conditional stimuli. Given that negative evaluations predict return of fear, the current study examined whether verbalisation strategies combined with listening to liked, non-lyrical background music enhanced expectancy learning and positively changed stimulus evaluations. A differential Pavlovian conditioning procedure was used involving fear acquisition, extinction, and extinction retest phases. Participants were assigned to a verbalisation condition (N = 21), a verbalisation plus liked, non-lyrical music condition (N = 21) or a control condition (N = 21) during extinction. The verbalisation strategies, with and without music, prevented the generalisation of US expectancies to safe stimuli at retest. Verbalisation strategies plus music increased positive evaluations of conditional stimuli during extinction and retest. Further research on the role of verbalising attention regulation strategies and liked, non-lyrical background music during extinction is warranted with clinical samples.

Imagery Rescripting Versus Extinction: Distinct and Combined Effects on Expectancy and Revaluation Learning

Anxiety disorders are effectively treated with exposure therapy, but relapse remains high. Fear may reinstate after reoccurrence of the negative event because the expectancy of the aversive outcome (unconditioned stimulus [US]) is adjusted but not its evaluation. Imagery rescripting (ImRs) is an intervention that is proposed to work through revaluation of the US. The aim of our preregistered study was to test the effects of ImRs and extinction on US expectancy and US revaluation. Day 1 ( n = 106) consisted of acquisition with an aversive film clip as US. The manipulation (ImRs + extinction, extinction-only, or ImRs-only) took place on Day 2. Reinstatement of fear was tested on Day 3. Results showed expectancy learning in both extinction conditions but not in the ImRs-only condition and no enhanced revaluation learning in ImRs. The combination of ImRs and extinction slowed down extinction but did not protect against reinstatement, which pleads in favor of stand-alone interventions in clinical practice.

Generalization gradients for fear and disgust in human associative learning

Previous research indicates that excessive fear is a critical feature in anxiety disorders; however, recent studies suggest that disgust may also contribute to the etiology and maintenance of some anxiety disorders. It remains unclear if differences exist between these two threat-related emotions in conditioning and generalization. Evaluating different patterns of fear and disgust learning would facilitate a deeper understanding of how anxiety disorders develop. In this study, 32 college students completed threat conditioning tasks, including conditioned stimuli paired with frightening or disgusting images. Fear and disgust were divided into two randomly ordered blocks to examine differences by recording subjective US expectancy ratings and eye movements in the conditioning and generalization process. During conditioning, differing US expectancy ratings (fear vs. disgust) were found only on CS-, which may demonstrated that fear is associated with inferior discrimination learning. During the generalization test, participants exhibited greater US expectancy ratings to fear-related GS1 (generalized stimulus) and GS2 relative to disgust GS1 and GS2. Fear led to longer reaction times than disgust in both phases, and the pupil size and fixation duration for fear stimuli were larger than for disgust stimuli, suggesting that disgust generalization has a steeper gradient than fear generalization. These findings provide preliminary evidence for differences between fear- and disgust-related stimuli in conditioning and generalization, and suggest insights into treatment for anxiety and other fear- or disgust-related disorders.

Reducing Generalization of Conditioned Fear: Beneficial Impact of Fear Relevance and Feedback in Discrimination Training.

Anxiety patients over-generalize fear, possibly because of an incapacity to discriminate threat and safety signals. Discrimination trainings are promising approaches for reducing such fear over-generalization. Here we investigated the efficacy of a fear-relevant vs. a fear-irrelevant discrimination training on fear generalization and whether the effects are increased with feedback during training. Eighty participants underwent two fear acquisition blocks, during which one face (conditioned stimulus, CS+), but not another face (CS−), was associated with a female scream (unconditioned stimulus, US). During two generalization blocks, both CSs plus four morphs (generalization stimuli, GS1–GS4) were presented. Between these generalization blocks, half of the participants underwent a fear-relevant discrimination training (discrimination between CS+ and the other faces) with or without feedback and the other half a fear-irrelevant discrimination training (discrimination between the width of lines) with or without feedback. US expectancy, arousal, valence ratings, and skin conductance responses (SCR) indicated successful fear acquisition. Importantly, fear-relevant vs. fear-irrelevant discrimination trainings and feedback vs. no feedback reduced generalization as reflected in US expectancy ratings independently from one another. No effects of training condition were found for arousal and valence ratings or SCR. In summary, this is a first indication that fear-relevant discrimination training and feedback can improve the discrimination between threat and safety signals in healthy individuals, at least for learning-related evaluations, but not evaluations of valence or (physiological) arousal.

A common genetic variant in fatty acid amide hydrolase is linked to alterations in fear extinction neural circuitry in a racially diverse, nonclinical sample of adults.

Poor fear extinction learning and recall are linked to the development of fear-based disorders, like posttraumatic stress disorder, and are associated with aberrant activation of fear-related neural circuitry. This includes greater amygdala activation during extinction learning and lesser hippocampal and ventromedial prefrontal cortex (vmPFC) activation during recall. Emerging data indicate that genetic variation in fatty acid amide hydrolase (FAAH C385A; rs324420) is associated with increased peripheral endocannabinoid (eCB) levels and lesser threat-related amygdala reactivity. Preclinical studies link increased eCB signaling to better extinction learning and recall, thus FAAH C385A may protect against the development of trauma-related psychopathology by facilitating extinction learning. However, how this FAAH variant affects fear extinction neural circuitry remains unknown. In the present study, we used a novel, immersive-reality fear extinction paradigm paired with functional neuroimaging to assess FAAH C385A effects on fear-related neural circuitry and conditioned fear responding (US expectancy ratings, subjective units of distress, and skin conductance responding) in healthy adults from an urban area (Detroit, MI; N=59; C/C=35, A-carrier=24). We found lesser amygdala activation in A-allele carriers, compared to C/C homozygotes, during early extinction recall. Likewise, we found lesser dorsal anterior cingulate cortex and greater hippocampus activation in early extinction learning in A-carriers compared to C/C homozygotes. We found no effects of FAAH C385A on vmPFC activation or behavioral fear indices. These data support and extend previous findings that FAAH genetic variation, associated with increased eCB signaling and subsequent enhanced fear extinction, may predict individual differences in successful fear learning.

Fear conditioning and stimulus generalization in association with age in children and adolescents

The aim of the study was to investigate age-related differences in fear learning and generalization in healthy children and adolescents (n = 133), aged 8–17 years, using an aversive discriminative fear conditioning and generalization paradigm adapted from Lau et al. (2008). In the current task, participants underwent 24 trials of discriminative conditioning of two female faces with neutral facial expressions, with (CS+) or without (CS−) a 95-dB loud female scream, presented simultaneously with a fearful facial expression (US). The discriminative conditioning was followed by 72 generalization trials (12 CS+, 12 GS1, 12 GS2, 12 GS3, 12 GS4, and 12 CS−): four generalization stimuli depicting gradual morphs from CS+ to CS− in 20%-steps were created for the generalization phases. We hypothesized that generalization in children and adolescents is negatively correlated with age. The subjective ratings of valence, arousal, and US expectancy (the probability of an aversive noise following each stimulus), as well as skin conductance responses (SCRs) were measured. Repeated-measures ANOVAs on ratings and SCR amplitudes were calculated with the within-subject factors stimulus type (CS+, CS−, GS1-4) and phase (Pre-Acquisition, Acquisition 1, Acquisition 2, Generalization 1, Generalization 2). To analyze the modulatory role of age, we additionally calculated ANCOVAs considering age as covariate. Results indicated that (1) subjective and physiological responses were generally lower with increasing age irrespective to the stimulus quality, and (2) stimulus discrimination improved with increasing age paralleled by reduced overgeneralization in older individuals. Longitudinal follow-up studies are required to analyze fear generalization with regard to brain maturational aspects and clarify whether overgeneralization of conditioned fear promotes the development of anxiety disorders or vice versa.

Does the assessment of different combinations of within-phase subjective measures influence electrodermal responding and between-phase subjective ratings during fear conditioning and extinction experiments?

The type and number of dependent measures assessed have varied between fear conditioning and extinction experiments and it remains unclear whether methodological differences influence results. Measuring skin conductance responses (SCRs) and between-phase subjective ratings between four conditions; Con condition had no within-phase ratings; US Exp condition included within-phase US expectancy ratings only; CS Eval condition included within-phase CS evaluations only and All Meas condition included both. All Meas condition exhibited larger SCRs compared to other conditions during acquisition, extinction, and return of differential responding at test. Differential SCRs did not extinguish in CS Eval and Con conditions, and CS Eval condition exhibited smaller CS- SCRs than other conditions throughout phases. US Exp condition revealed differential conditioning, successful extinction, and no return of differential SCRs. Between-phase ratings were not affected by within-phase ratings. Researchers should consider assessing different combinations of within-phase subjective ratings depending on the aims of their research.

Trajectories of fear learning in healthy participants are able to distinguish groups that differ in individual characteristics, chronicity of fear and intrusions

Background and objectivesStudies on the development and treatment of anxiety disorders mostly focus on the comparison of predefined groups. An alternative approach is to use data-driven latent class growth analyses (LCGA) to determine differentiation between groups based on particular mechanistic factors. This study validated the use of LCGA on responses in a compact fear conditioning task and whether specific characteristics are associated with maladaptive fear learning trajectories. MethodsHealthy subjects (N = 300) completed a fear conditioning task that included uninstructed and instructed acquisition and extinction phases. Subjective fearfulness and US expectancy were used as outcome measures. Latent classes in the responses to the CS+ (coupled with a scream) and the CS- (control stimulus) were determined based on trajectories across the experimental phases. State and trait anxiety were measured during testing, and return of fear and intrusions were measured one and six weeks later. ResultsFear learning trajectories of poor extinction in responding to the CS+ and generalization of fear to the CS- were associated with higher state and trait anxiety. Individuals belonging to these trajectories reported more intrusions, fear and had higher US expectancy ratings after 1 week. LimitationsOnly 56% of participants completed the six weeks follow-up measures. ConclusionFear learning trajectories are associated with individual characteristics, return of fear and intrusions. Next, this task will be implemented in clinical practice to assess its predictive power for the extent to which patients benefit from exposure treatments.

Can you escape the virtual room? A novel paradigm to assess avoidance behaviour

Anxiety patients often experience conflicts between approaching (pass barking dog) and avoiding (take detour) feared situations. In most experimental avoidance paradigms, response options are limited or forced, making it difficult to generalize the results to daily life situations. The aim of the present study was twofold: 1) to develop a more ecologically valid avoidance paradigm; 2) to examine the influence of individual characteristics (trait anxiety; distress tolerance) on approach-avoidance behaviour. To encourage free exploration behaviour, a virtual reality (VR) escape room was developed. In this room, participants searched for cues to decipher a code-locked door. Opening a marked vase (conditioned stimulus, CS) was followed by a jump scare, a rat jumping out of the vase (unconditioned stimulus, US). Avoidance was measured via questionnaires and relative manipulation time of CS-marked (EXPgen) or nonmarked (CONT) objects in the room; questionnaires measured trait anxiety and distress tolerance. EXPgen participants reported higher US expectancies and more avoidance of the (marked) vase compared to the CONT participants, yet behavioural data did not support these ratings. Additionally, higher trait anxiety scores coincided with higher US expectancies before the jump scare. The current flexible free-exploratory paradigm provides multiple opportunities to examine avoidance behaviour in different populations and settings.

Differences in perceptual memory determine generalization patterns

Although memory of past experiences is crucial for the ability to transfer knowledge to new situations, surprisingly little research has directly investigated the relationship between memory and generalization. The present study sought to investigate how the perceptual memory of a trained stimulus influences generalization to similar stimuli. Forty participants underwent a fear conditioning procedure on Day 1, and separate memory recall and generalization tests on Day 2. We focused on two aspects of perceptual memory: namely memory bias (i.e., over- or underestimation of stimulus magnitude) and uncertainty. We found that memory bias predicted the pattern of generalized self-reported (expectancy ratings) and psychophysiological responses (fear-potentiated startle responses). Memory uncertainty was measured in two ways: self-reported uncertainty ratings and variability in stimulus recall. We found that higher levels of self-reported memory uncertainty corresponded with a broader generalization gradient on US expectancy, while greater variability in memory recall was associated with a broader generalization gradient on fear-potentiated startle responses. Taken together, our findings suggest that memory is an important determinant of generalized behavior and illustrate the need to account for these interindividual differences in perceptual memory when examining the generalization of learned responses.

Estimating nominal interest rate expectations: Overnight indexed swaps and the term structure

Abstract No-arbitrage dynamic term structure models (DTSMs) have regularly been used to estimate interest rate expectations and term premia, but are beset by empirical challenges. I propose augmenting DTSMs with overnight indexed swap (OIS) rates to better estimate the decomposition along the term structure at daily frequencies. A Gaussian affine DTSM, augmented with 3 to 24-month OIS rates, generates estimates of US expectations that closely correspond to survey-implied measures out to a 10-year horizon and are more stable across sub-samples, compared to existing models. In addition, I provide narrative evidence, in the form of an event study around US unconventional monetary policy announcements, to further exemplify the benefits from OIS augmentation.

Conjunctive and Elemental Representations of a Context in Humans.

The dual-process theory assumes that contexts are encoded in an elemental and in a conjunctive representation. However, this theory was developed from animal studies, and we still have to explore if and how elemental and conjunctive representations contribute to, for example, contextual anxiety in humans. Therefore, 28 participants underwent differential context conditioning in a newly developed flip-book paradigm. Virtual rooms were presented similar to a flip-book, that is, as a stream of 49 consecutive screenshots creating the impression of walking through the rooms. This allowed registration of event-related brain potentials triggered by specific screenshots. During two acquisition phases, two rooms were shown in this way for six times each. In one room, the anxiety context (CTX+), mildly painful electric stimuli (unconditioned stimuli [USs]) were administered unpredictably after 12 distinct screenshots, which became threat elements, whereas 12 selected comparable screenshots became nonthreat elements (elemental representation); all screenshots represented the anxiety context (conjunctive representation). In the second room, the safety context (CTX-), no USs were applied; thus, all screenshots created the safety context whereby 12 preselected screenshots represented safety elements. Increased US expectancy ratings for threat versus nonthreat or safety elements reflected elemental representation. Conjunctive representation was evident in differential ratings (arousal and contingency) and increased P100 and early posterior negativity amplitudes for threat and nonthreat CTX+ versus safety CTX- screenshots. These differences disappeared during two test phases without US delivery indicating successful extinction. In summary, we revealed the first piece of evidence for the simultaneous contributions of elemental and conjunctive representation during context conditioning in humans.

Fear Learning in Veterans With Combat-Related PTSD Is Linked to Anxiety Sensitivity: Evidence From Self-Report and Pupillometry

Several studies have observed heightened Pavlovian fear conditioning in PTSD. However, it is unclear how fear conditioning in PTSD is related to risk factors for the disorder, such as anxiety sensitivity. Fifty-one combat-exposed veterans (20 with PTSD, 31 without PTSD) completed a differential fear conditioning task in which one colored rectangle (CS+) predicted a loud scream (US), whereas a different colored rectangle (CS-) predicted no US. Veterans with PTSD were characterized by greater anxiety to the CS+ but not the CS- during acquisition and extinction, and greater US expectancy during the CS+ but not the CS- at extinction. Also, veterans with PTSD had greater pupil dilation to both CSs at extinction, but not at acquisition. Anxiety sensitivity was correlated with anxiety and US expectancy in response to the CS+, but not the CS-, at both acquisition and extinction, and also with pupil diameter to both the CS+ and CS- at extinction. Nearly all of these relations held when covarying for PTSD symptoms and trait anxiety. These findings suggest that increased fear conditioning in PTSD may be related to elevated anxiety sensitivity.

Costly avoidance triggered by categorical fear generalization

Fear generalization refers to the spread of acquired fear to novel stimuli that resemble the original fear-related stimulus. Preliminary evidence suggests that excessive fear generalization is a pathogenic feature of anxiety disorders, however, it remains unclear how fear generalization affects pathological avoidance. The current study thus aimed to examine the link between categorical fear generalization and costly avoidance. By combining a fear acquisition training phase and an avoidance test, the current findings showed that acquired fear spreads to novel stimuli that belonged to the same category of the original fear-related stimuli, but not to those that belonged to the fear-irrelevant categories. Importantly, participants avoided these fear-related novel stimuli despite costs. The current findings indicate that categorical fear generalization triggers costly avoidance. In terms of clinical implication, a decrease in costly avoidance aligned with a decrease in US expectancies. This emphasizes that behavioral approach may initiate extinction learning.

Fearful Faces and the Derived Transfer of Aversive Functions

Studies suggest that fear-related responses might be acquired through the facial expressions of other individuals. The present study aimed to investigate the derived transfer of aversive functions in equivalence classes comprised of facial expressions of fear and happiness. A delayed matching-to-sample task established two equivalence classes between facial expressions of emotions and nonsense abstract stimuli: B1-A1(Fear)-C1-D1; B2-A2(Happiness)-C2-D2. After relational training (AB, AC, CD) and equivalence tests (BD, DB), the transfer of function from the faces to the D stimuli was evaluated by means of (1) a semantic differential, (2) an avoidance task, (3) US expectancy scale, and (4) valence scale. Results from the semantic differential indicated that D1 and D2 had negative and positive evaluations, respectively. Fear related measures indicated that D1 (equivalent to fear) evoked avoidance responses, was highly rated on US expectancy and was negatively valenced; in comparison, D2 (equivalent to happy) did not evoke either avoidance or US expectancy and was positively valenced. These findings indicate that the participation of fearful faces in equivalence classes leads to derived fear, including derived avoidance responses.

The association between fear extinction, the ability to accomplish exposure and exposure therapy outcome in specific phobia

Great interest exists in maximizing exposure therapy efficacy in anxiety disorders. At the same time, reduced frequency and shortened duration of exposure sessions are required to meet the specific regularities in routine care settings. Extinction has emerged as the key mechanism of exposure treatment in anxiety disorders. Examining exposure treatment processes from the perspective of extinction learning might provide novel insights into variability in exposure treatment duration and outcome. The present study sought to examine the functional link between fear extinction, the ability to accomplish exposure in a predetermined time and exposure therapy outcome in specific phobia. Treatment-seeking individuals (N = 53) with spider phobia underwent a context-dependent fear conditioning paradigm prior to a standardized exposure. Spider-phobic participants who were able to complete exposure within the pre-determined time (i.e., completers) showed a more pronounced short- and long-term exposure therapy benefit. In the fear conditioning task, a more pronounced decline in CS-US contingency ratings during extinction (retrieval) was found in completers relative to non-completers. The failure to further extinguish US expectancy to the CSs in non-completers might offer a potential mechanistic explanation why non-completers have difficulties to accomplish all exposure steps in a fixed time and show less pronounced treatment gains. Our findings bear specific implications for the implementation of exposure treatment to routine care settings.

Generalization of extinction of a generalization stimulus in fear learning

Two experiments examined whether extinction of a generalization stimulus (GS) after single cue fear conditioning would in turn generalize to other stimuli, relative to a control group that received regular extinction of CS + itself. We found only a weak effect of such “generalization of GS extinction” either back to CS + or to a different GS, on either US expectancy or skin conductance measures. In other words, despite extinction trials with a stimulus highly similar to CS+, participants showed a return of fear when tested with CS + or a novel GS. However this responding declined rapidly over non-reinforced test trials. Trait anxious participants showed higher overall US expectancy ratings in the extinction and test phases, and slower extinction of expectancy, relative to low anxious participants. These results may help explain why exposure therapy, which is unlikely to reproduce the exact stimuli present at acquisition, sometimes fails to transfer to other fear-eliciting stimuli subsequently encountered by anxious clients. The generalization of GS extinction paradigm might provide a useful testbed for evaluation of interventions designed to enhance transfer, such as exposure to multiple diverse exemplars.