Evaluative conditioning of fear and disgust in blood-injection-injury phobia: specificity and impact of individual differences in disgust sensitivity

Conceptual-level disgust conditioning in contamination-based obsessive-compulsive disorder

Pavlovian fear conditioning and extinction represent learning mechanisms underlying exposure-based interventions. While increasing evidence indicates a pivotal role of disgust in the development of contamination-based obsessive-compulsive disorder (C-OCD), dysregulations in conditioned disgust acquisition and maintenance, in particular driven by higher-order conceptual processes, have not been examined. Here, we address this gap by exposing individuals with high (HCC, n = 41) or low (LCC, n = 41) contamination concern to a conceptual-level disgust conditioning and extinction paradigm. Conditioned stimuli (CS+) were images from one conceptual category partially reinforced by unconditioned disgust-eliciting stimuli (US), while images from another category served as non-reinforced conditioned stimuli (CS-). Skin conductance responses (SCRs), US expectancy and CS valence ratings served as primary outcomes to quantify conditioned disgust responses. Relative to LCC, HCC individuals exhibited increased US expectancy and CS+ disgust experience, but comparable SCR levels following disgust acquisition. Despite a decrease in conditioned responses from the acquisition phase to the extinction phase, both groups did not fully extinguish the learned disgust. Importantly, the extinction resilience of acquired disgust was more pronounced in HCC individuals. Together, our findings suggest that individuals with high self-reported contamination concern exhibit increased disgust acquisition and resistance to extinction. The findings provide preliminary evidence on how dysregulated disgust learning mechanism across semantically related concepts may contribute to C-OCD.

Is disgust more resistant to extinction than fear? A meta-analytic review of laboratory paradigms

Disgust can be acquired via evaluative conditioning; a process by which a neutral stimulus (conditioned stimulus; CS) comes to be evaluated as disgusting due to its pairing with an inherently disgusting stimulus (unconditioned stimulus; US). Research has shown that conditioned disgust responses are resistant to extinction which may have implications for disorders (i.e., contamination-based obsessive-compulsive disorder, specific phobias, and post-traumatic stress disorder) in which heightened disgust has been implicated. Importantly, extinction is the primary mechanism by which exposure therapies are thought to achieve symptom reduction for these disorders. Exposure therapies were originally modeled on fear extinction, whereas disgust extinction was largely overlooked until recently. Accordingly, differences in the degree to which learned disgust and fear can be attenuated via extinction learning remains unclear. The present investigation was a meta-analysis directly comparing the degree of extinction of conditioned disgust (n = 14) and conditioned fear (n = 14) in laboratory paradigms. Extinction was operationalized as the standardized mean difference (SMD) in evaluative ratings between the CS+ (the CS paired with the US) and CS- (the unpaired CS) after extinction training. Results of a subgroup analysis indicated that disgust (SMD = 0.52) was significantly more resistant to extinction than fear (SMD = 0.37). Additionally, a series of meta-regression analyses indicated that extinction was not influenced by important study characteristics (e.g., sex, age, number of conditioning and extinction trials). The findings suggest that extinction-based approaches may be less effective at attenuating learned disgust and research is needed to better optimize treatments for disgust-related disorders.

Treatment of disgust in specific emotional disorders

Although conditioning approaches have highlighted potential characteristics of disgust in anxiety disorders, obsessive-compulsive disorder (OCD), and posttraumatic stress disorder (PTSD), these findings have yet to be translated into evidence-based treatments. Examination of the literature suggests various indicators of disgust that predict treatment outcome in these disorders. However, mechanisms remain unclear because studies examining disgust during the course of treatment are limited. Increasingly, the field has moved toward experimental investigation of strategies that reduce disgust. While cognitive reappraisal and imagery techniques appear promising, such techniques have yet to be examined as anxiety disorder treatments in large-scale randomized clinical trials. The literature also points to novel approaches to treating disgust, ranging from an inhibitory-informed approach to exposure therapy to transcranial direct current stimulation. However, the development of novel treatment approaches will require more rigorous experimental psychopathology approaches that can further elucidate processes that contribute to the etiology and/or maintenance of disorders of disgust.

Pavlovian Disgust Conditioning and Generalization: Specificity and Associations With Individual Differences

Although studies have identified differences between fear and disgust conditioning, much less is known about the generalization of conditioned disgust. This is an important gap in the literature given that overgeneralization of conditioned disgust to neutral stimuli may have clinical implications. To address this knowledge gap, female participants (n = 80) completed a Pavlovian conditioning procedure in which one neutral food item (conditioned stimulus; CS+) was followed by disgusting videos of individuals vomiting (unconditioned stimulus; US) and another neutral food item (CS-) was not reinforced with the disgusting video. Following this acquisition phase, there was an extinction phase in which both CSs were presented unreinforced. Importantly, participants also evaluated generalization stimuli (GS+, GS-) that resembled, but were distinct from, the CS after each conditioning phase. As predicted, the CS+ was rated as significantly more disgusting and fear inducing than the CS- after acquisition and this pattern persisted after extinction. However, disgust ratings of the CS+ after acquisition were significantly larger than fear ratings. Participants also rated the GS+ as significantly more disgusting, but not fear inducing, than the GS- after acquisition. However, this effect was not observed after extinction. Disgust proneness did predict a greater increase in disgust and fear ratings of the CS+ relative to the CS- after acquisition and extinction. In contrast, trait anxiety predicted only higher fear ratings to the CS+ relative to the CS- after acquisition and extinction. Disgust proneness nor trait anxiety predicted the greater increase in disgust to the GS+ relative to the GS- after acquisition. These findings suggest that while conditioned disgust can generalize, individual difference variables that predict generalization remain unclear. The implications of these findings for disorders of disgust are discussed.

The role of self-reported fear and disgust in the activation of behavioral harm avoidance related to medical settings

INTRODUCTION

Although adaptive defense mechanisms are useful in helping us avoid getting injured, they are also triggered by medical interventions and procedures, when avoidance is harmful. A body of previous results showed that both fear and disgust play a pivotal role in medical avoidance. However, the underlying mechanisms are not fully understood. Thus, the aim of the current study was to examine the effects of experience, perceived control, and pain on medical avoidance with disgust and fear as mediating factors from an evolutionary perspective.

METHODS

We assessed participants' knowledge of and experience with medical procedures, former negative medical experiences, and health-related information; their life history strategy variation; pain-related fear and anxiety of medical procedures; perceived control over emotional reactions and extreme threats; disgust sensitivity; blood-injury-injection phobia and medical treatment avoidance.

RESULTS

We found that more knowledge, experience, and a slower life strategy were linked to a greater level of perceived control and attenuated emotional reactions. Further, better ability to control affective and stress reactions to negative experiences was linked to reduced disgust and fear of pain, and thus might mitigate the level of perceived threat, and diminish fear and disgust reactions.

DISCUSSION

More knowledge and experiences, better perceived control together with reduced disgust and fear of pain can decrease the probability of avoiding medical situations. Implications to treatment are discussed. Results support the importance of targeting these contextual factors in prevention to increase the likelihood of people attending regular screenings or seeking medical care when needed.

Is Acquired Disgust More Difficult to Extinguish Than Acquired Fear? an Event-Related Potential Study

This study used the classical conditioned acquisition and extinction paradigm to compare which of the two emotions, acquired disgust and acquired fear, was more difficult to extinguish, based on behavioral assessments and the event-related potential (ERP) technique. Behavioral assessments revealed that, following successful conditioned extinction, acquired disgust was more difficult to extinguish. The ERP results showed that, at the early stage of P1, the amplitude of conditioned fear was significantly smaller than that of conditioned disgust, and both were significantly different from the amplitude under neutral conditions; at the middle stage of N2, the difference between the amplitudes of conditioned disgust and conditioned fear disappeared, but they were still significantly different from the amplitudes of conditioned neutral stimuli; at the late stage of P3, the difference between conditioned disgust and conditioned neutral stimuli disappeared, but the difference between conditioned fear and neutral stimuli remained, suggesting that acquired fear was more difficult to extinguish than acquired disgust in terms of how the brain works.

Fear conditioning and extinction in obsessive-compulsive disorder: A systematic review

Laboratory experiments using fear conditioning and extinction protocols help lay the groundwork for designing, testing, and optimizing innovative treatments for anxiety-related disorders. Yet, there is limited basic research on fear conditioning and extinction in obsessive-compulsive disorder (OCD). This is surprising because exposure-based treatments based on associative learning principles are among the most popular and effective treatment options for OCD. Here, we systematically review and critically assess existing aversive conditioning and extinction studies of OCD. Across 12 studies, there was moderate evidence that OCD is associated with abnormal acquisition of conditioned responses that differ from comparison groups. There was relatively stronger evidence of OCD's association with impaired extinction processes. This included multiple studies finding elevated conditioned responses during extinction learning and poorer threat/safety discrimination during recall, although a minority of studies yielded results inconsistent with this conclusion. Overall, the conditioning model holds value for OCD research, but more work is necessary to clarify emerging patterns of results and increase clinical translational utility to the level seen in other anxiety-related disorders. We detail limitations in the literature and suggest next steps, including modeling OCD with more complex conditioning methodology (e.g., semantic/conceptual generalization, avoidance) and improving individual-differences assessment with dimensional techniques.

Acquisition and maintenance of disgust reactions in an OCD analogue sample: Efficiency of extinction strategies through a counter-conditioning procedure

BACKGROUND

Obsessive-compulsive disorder (OCD) has long been considered as an anxiety disorder, disgust is the dominant emotion in contamination-based OCD. However, disgust seems resistant to exposure with response prevention partly due to the fact that disgust is acquired through evaluative conditioning.

AIMS

The present research investigates a counter-conditioning intervention in treating disgust-related emotional responses in two groups of individuals with high (High contamination concerns, HCC, n = 24) and low (Low contamination concerns LCC, n = 23) contamination concerns.

METHODS

The two groups completed a differential associative learning task in which neutral images were followed by disgusting images (conditioned stimulus; CS+), or not (CS-). Following this acquisition phase, there was a counter-conditioning procedure in which CS+ was followed by a very pleasant unconditional stimulus while CS- remained unreinforced.

RESULTS

Following counter-conditioning, both groups reported significant reduction in their expectancy of US occurrence and reported less disgust with CS+. For both expectancy and disgust, reduction was lower in the HCC group than in the LCC group. Disgust sensitivity was highly correlated with both acquisition and maintenance of the response acquired, while US expectation was predicted by anxiety.

CONCLUSION

Counter-conditioning procedure reduces both expectations and conditioned disgust.

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.

Disgust assessment: Factorial structure and psychometric properties of the French version of the Disgust Propension and Sensibility Scale Revised-12

The present study examined the internal and external validity of the French version of the 12-item Disgust Propensity and Sensitivity Scale-Revised (DPSS-12) in a nonclinical sample from the general population. Two hundred and eighty-two participants completed the DPSSf-12 questionnaire as well as the Anxiety Sensitivity Index (ASI), Anxiety Trait (STAI B), Obsessional Belief Questionnaire 44 items (OBQ 44), Obsessive Compulsive Inventory-Revised (OCI-R) and Positive and Negative Affect Schedule (PANAS). Confirmatory Factor Analysis supported a 2-factor structure after two sensitivity items were removed. The 10-item scale showed good internal consistency, construct validity and test-retest reliability. These adequate psychometric properties make the DPSSf-10 appropriate for use by researchers and practitioners.

Effect of Partners' Disgust Responses on Psychological Wellbeing in Cancer Patients

The aim of this study was to explore quantitatively the relationship between disgust responses in cancer patients and their partners, and in turn their relationship to patients' psychological well-being. We recruited 50 participants with heterogeneous cancer diagnoses and their partners from cancer-related groups (e.g., charities). Patients completed questionnaires to determine levels of disgust propensity, disgust sensitivity, self-disgust, and symptoms of anxiety and depression. Disgust propensity and sensitivity were also assessed in their partners. Partners' disgust sensitivity was significantly positively correlated with cancer patients' self-disgust, disgust propensity, and depression. Path analyses suggested that patients' self-disgust plays a role in mediating the effect of partners' disgust sensitivity on patients' psychological well-being. This study provides the first quantitative evidence that psychological well-being in cancer patients is contingent on their partners' sensitivity to disgust, and that patients' self-disgust plays a mediating role. Focusing therapeutically on disgust responses could well be beneficial to people with cancer.

Reliability, validity and cutoff score of the Intra-Oral Injection Fear scale

BACKGROUND

A proper assessment tool is needed to gain more knowledge about fear of intraoral injections in children.

AIM

The aims of this study were to evaluate the reliability and validity of the novel Intra-Oral Injection Fear scale (IOIF-s) and to establish a cutoff score for a high level of such fear.

METHODS

Data were obtained from two samples of 10- to 16-year-olds in Hordaland, Norway. Sample I, 1460 pupils attending elementary and high schools, provided questionnaire-based data. The survey instruments used were IOIF-s, Children's Fear Survey Schedule-Dental Subscale (CFSS-DS), Mutilation Questionnaire for Children (MQ-c) and Injection phobia Scale for Children (IS-c). Sample II was 67 patients, diagnosed with intraoral injection phobia at the Center for Odontophobia, Oral Health Center of Expertise in Western Norway-Hordaland, who provided IOIF-s data.

RESULTS

Cronbach's alpha was 0.95. The IOIF-s discriminated between subjects with and without intraoral injection phobia and was associated with the other survey instruments of similar construct. Principal component analysis revealed a two-component solution, characterized as 'Contact Fear' and 'Distal Fear'. Receiver-operating characteristic (ROC) curve indicated that a cutoff score of 38 was appropriate.

CONCLUSION

The IOIF-s showed satisfying psychometric properties in terms of reliability and validity.

Further Psychometric Evaluation of the Child Disgust Scale

This study evaluated the psychometric properties of the Child Disgust Scale (CDS) among 457 youth (ages 8-17, M = 14.77 ± 1.98 years) initiating residential treatment for obsessive-compulsive disorder and anxiety disorders. Confirmatory factor analysis supported a bifactor model with two distinct factors of Disgust Avoidance and Disgust Affect, in addition to an overall General Disgust factor. Strong internal consistency was observed for the CDS total and factor scores. In addition, CDS scores demonstrated generally modest and positive correlations with child-reported obsessive-compulsive and anxiety symptoms, weaker correlations with parent-reported anxiety and child-rated impairment, and non-significant correlations with parent-rated impairment. Findings suggest that the CDS displays strong psychometric properties and is developmentally appropriate for use in pediatric clinical populations with obsessive-compulsive and anxiety disorders.

Discriminative evaluative conditioning in the long-term after severe accidental injury

Impairments in classical fear conditioning and deficits in discriminative learning are observed in posttraumatic stress disorder (PTSD). However, it is unknown whether similar impairments can be found with types of discriminative learning other than classical conditioning, such as evaluative conditioning (EC), in which the valence of a stimulus can be transferred to other stimuli. In this study, we investigated whether EC is also influenced by traumatic experiences independently of presence of PTSD. We tested 14 accident survivors with remitted PTSD, 14 survivors without PTSD, and 16 non-trauma controls. We used behavioral measures, psychophysiological indicators, and subjective ratings for tasks. General effects of learning were observed across groups and conditioning/extinction. Trauma controls had slower reaction times (RTs) to the aversive conditioned stimulus compared to appetitive conditioned and neutral stimuli, as well as slower RTs and increased accuracy during conditioning than during extinction. Remitted PTSD participants showed opposite results, demonstrating decreased accuracy and slower RTs during conditioning as compared to during extinction. No discriminative effect was found in the non-trauma controls and the remitted PTSD participants. These results suggest that a traumatic experience influences EC, and that this influence differs between individuals who have and have not developed PTSD after traumatic exposure.

Effective behavioural strategies for reducing disgust in contamination-related OCD: A review

Disgust is an understudied but important emotion in various psychological disorders. Over the last decade, increasing evidence suggests that disgust is also present in various subtypes of obsessive-compulsive disorder (OCD), especially in contamination-related OCD (C-OCD). The treatment of choice for C-OCD is exposure with response prevention, originally designed to reduce fear-associated emotions thought to be acquired through Pavlovian conditioning (PC). However, disgust has been proposed to be acquired through evaluative conditioning (EC) and according to the referential model of this form of learning, there are functional differences between PC and EC that need to be considered in the treatment of disgust-related responses. Alternative strategies suggested by EC-based models include counterconditioning (contingent presentation of the CS with a US of opposite valence) and US revaluation (contingent presentation of the US with US of opposite valence). Drawing on the referential model, this paper reviews evidence for the effectiveness of each strategy to identify the most theoretically sound and empirically valid intervention to reduce disgust in C-OCD.

Development and initial validation of the Child Disgust Scale

Although disgust sensitivity (DS) has been implicated in the development of anxiety disorders in children, the absence of a measure of DS specifically for children has not allowed for an adequate test of this claim. To fill this important gap in the literature, this investigation presents a series of studies on the development and examination of the psychometric properties (including reliability, validity, and factor structure) of scores on a newly developed Child Disgust Scale (CDS). Exploratory factor analysis in Study 1 (N = 1,500) found that a bifactor model, which allows for a "g" DS factor in addition to 2 distinct factors of Disgust Avoidance and Disgust Affect, was the best fit for the data. Study 2 (N = 573) confirmed a two-factor bifactor model above and beyond a 1-factor model that controlled for method effects due to reverse-worded items. Results from Study 3 (N = 50) provided support for convergent and discriminant validity such that scores on the CDS were significantly correlated with measures of anxiety and fear, but not depression. Finally, Study 4 (N = 86) found that the CDS differentiated children with a diagnosis of specific phobia (n = 43) from a matched nonclinical community sample of children (n = 43), such that those with a specific phobia reported greater DS compared with controls. Results from these studies suggest that the CDS is a developmentally appropriate measure with good psychometric properties that can aid research on the role of disgust sensitivity in anxiety-related disorders in children.

Don't look now! Oculomotor avoidance as a conditioned disgust response

Pavlovian conditioning paradigms have revealed fear learning tendencies that may be implicated in the etiology and maintenance of anxiety disorders. Given the prominence of disgust in certain anxiety disorders, it may be fruitful to study disgust learning in addition to fear learning. The present study utilized eye tracking to examine the effects of disgust conditioning on attentional bias, a phenomenon that characterizes anxiety disorders. Participants completed either a disgust condition, in which a face (conditioned stimulus; CS+) was paired with videos of individuals vomiting (unconditioned stimulus; US), or a negative condition in which a face was paired with videos of individuals being harmed in motor-vehicle accidents. Eye movements were used to measure attentional biases related to the USs and the CSs. In line with prior research, attentional avoidance was observed for the disgust CS+. However, this effect did not reach significance until after extinction and was linked to self-reported disgust postacquisition, yet decoupled from self-reported disgust postextinction. Attentional avoidance of the CS+ was not found in the negative condition, and postextinction differences in attentional bias for the CS+ between conditions were found to be mediated by differences in attentional bias for the US, as only the disgust US elicited attentional avoidance. Also, individual differences in disgust sensitivity were found to be associated with attentional avoidance of the disgust US, and this effect was mediated by self-reported disgust in response to the US. Further, disgust sensitivity was associated with attentional avoidance of the disgust CS+, and this effect was mediated by attentional avoidance of the disgust US. These findings provide new insight into a complex pattern of relations between disgust, evaluative learning, and attention that may have implications for the etiology and maintenance of certain anxiety disorders.

Implicit and explicit emotional behavior and mindfulness

The objective of this study was to examine whether the "step back and watch" attitude of mindfulness manifests in less emotional behavior. We hypothesized that the "acceptance" facet of mindfulness, but not the "presence" facet, is negatively associated with the magnitude of emotional behavior in four tests, i.e., (1) rating of words, (2) rating of aversive and neutral pictures, and (3) evaluative conditioning (EC). Additionally, we hypothesized that (4) the acceptance facet is associated with increased reaction time (RT) in an emotional Stroop test, and that the presence facet is associated with decreased RT and lower error rate. The sample consisted of N=247 non-clinical adults and was tested in a cross-sectional study. The results provide partial evidence that the acceptance facet of mindfulness may be associated with less aversive reactions towards aversive stimuli. Future studies should substantiate these findings but also determine their clinical relevance.

Disgust and the development of posttraumatic stress among soldiers deployed to Afghanistan

Although the DSM-IV recognizes that events can traumatize by evoking horror, not just fear, the role of disgust in the development of posttraumatic stress disorder (PTSD) has received little research attention. In a study of soldiers deployed to Afghanistan, we examined whether reports of peritraumatic disgust and trait disgust vulnerability factors (disgust propensity and disgust sensitivity) predict PTSD-symptoms, independently of peritraumatic fear, neuroticism, and anxiety sensitivity. Participants (N = 174) enrolled in this study before deployment, and were retested around 6 months (N = 138; 79%) and, again, 15 months (N = 107; 62%) after returning home. The results showed that (1) greater peritraumatic disgust and fear independently predicted PTSD-symptom severity at 6 months, (2) greater disgust propensity predicted more peritraumatic disgust, but not PTSD-symptom severity, and (3) disgust sensitivity moderated the relationship between peritraumatic disgust and PTSD-symptom severity. Implications of these findings for broadening the affective vulnerabilities that may contribute to PTSD will be discussed.

Disgust, anxiety, and vasovagal syncope sensations: a comparison of injection-fearful and nonfearful blood donors

Although research has implicated disgust in the fainting response observed in blood-injection-injury (BII) phobia, this finding has not been consistently observed in the literature. The present study further examines the relationship between disgust and fainting symptoms among injection-fearful (n=108) and nonfearful (n=338) blood donors. Volunteers from community blood drives provided pre-donation levels of anxiety and disgust towards giving blood and completed a standardized measure of vasovagal reactions (fainting) to blood donation after giving blood. As predicted, injection-fearful participants reported significantly more pre-donation anxiety and disgust compared to nonfearful participants. Injection-fearful donors also reported experiencing more fainting symptoms during blood donation and found the donation experience more unpleasant than did nonfearful participants. Although pre-donation disgust and anxiety levels each uniquely predicted fainting symptoms among nonfearful donors, only pre-donation anxiety uniquely predicted fainting symptoms among injection-fearful donors. Implications of these findings for conceptualizing the disgust-faint relationship in BII phobia are discussed.

Looking beyond fear: the extinction of other emotions implicated in anxiety disorders

Previous research examining anxiety has traditionally focused on models of fear. More recently, attention has been directed to the role of disgust as an important emotion in the context of certain anxiety disorders. Further, it has been suggested that disgust, a form of evaluative responding, may be resistant to extinction and may contribute to relapse. However, previous work on this has largely relied on self-report ratings. In the current experiment, using a disgust conditioning and extinction procedure, disgust reactions were indeed shown to be resistant to extinction, as indexed by both self-report and an objective behavioral measure (visual avoidance). Furthermore, our research shows that individuals with greater levels of disgust sensitivity exhibit heightened resistance to extinction. In addition, expectancy of the disgusting US during extinction was dissociated from measures of disgust responding. Given that the treatment of choice for anxiety disorders (exposure therapy) is based on models of extinction, this research suggests that current treatments for anxiety disorders may not be adequately targeting disgust reactions, a crucial maintaining factor in certain anxiety disorders. As such, this inattention to disgust reactions may reduce the effectiveness of treatment in the short-term or may leave the patient vulnerable to relapse in the long-term.

Neural, electrodermal and behavioral response patterns in contingency aware and unaware subjects during a picture-picture conditioning paradigm

One way of investigating affective learning is the use of aversive pictures as unconditioned stimuli (UCS) in conditioning paradigms. In the last decades, there has been a heated debate on the influence of contingency awareness on conditioned responses (CRs). Only a few studies found CRs in contingency unaware subjects whereas other studies only reported conditioned reactions in contingency aware participants. However, as a shortcoming, most studies employing picture-picture paradigms only investigated one response level (e.g. changes in subjective ratings). Further, changes in brain activity have so far been neglected in this field of research. The aim of the present study was to investigate different response levels with respect to contingency awareness: brain activity measured by functional magnetic resonance imaging (fMRI), skin conductance responses (SCRs) and valence ratings. A neutral geometric shape (conditioned stimulus, CS+) was followed by aversive pictures, whereas another shape (CS-) preceded neutral pictures. Unaware participants showed CRs in brain activity (e.g. the insula). Generally more activity was observed in the fear network (e.g. the amygdala, the lateral orbitofrontal cortex) in aware participants and in the nucleus accumbens (NAcc). Investigation of SCRs and valence ratings revealed that only aware participants showed conditioned reactions. Our results point toward dissociations between response levels (e.g. brain activity) not affected by contingency awareness and more cognitive response levels (e.g. subjective ratings and SCRs) which are affected by contingency awareness. As a unique finding in human aversive conditioning, we discuss the role of the nucleus accumbens as well as practical implications for affective learning models.