Understanding Disgust Propensity in Human Affective Processing

Disgust serves as a vital evolutionary defense mechanism that shields human beings from contamination, infectious pathogens, and physical hazards. However, individuals differ markedly in how frequently and intensely they experience this protective visceral emotion. In clinical psychology and affective neuroscience, researchers distinguish between two related but separate constructs: disgust propensity and disgust sensitivity. Disgust propensity represents an individual's dispositional tendency to experience disgust when encountering repulsive environmental stimuli. In contrast, disgust sensitivity refers to the secondary negative appraisal or cognitive dread associated with experiencing the emotion itself. Although theoretical frameworks have separated these dimensions for years, neuroimaging studies historically faced methodological constraints in mapping their distinct neural substrates. Consequently, understanding their specific neurobiological contributions remained an urgent question in psychiatric neuroscience. A landmark functional magnetic resonance imaging investigation by Gan and colleagues provides essential empirical clarification. Specifically, the researchers recruited a large cohort of 142 human participants to evaluate how trait disgust modulates neural activity during exposure to validated disgust-specific visual stimuli. By systematically controlling for varying levels of subjective emotional intensity, the investigators delineated the discrete neural circuits that govern primary affective reactivity.

Whole-Brain Neuroimaging Unveils Differential Neural Representations

The investigators conducted whole-brain voxel-wise regression analyses while participants viewed carefully calibrated visual images depicting diverse disgusting scenes. Remarkably, the neuroimaging data revealed a striking dissociation between the two dispositional traits. Disgust propensity robustly modulated neural activity across a widespread network of cortical, limbic, and subcortical brain regions. In particular, higher disgust propensity scores correlated with heightened activation across the anterior, middle, and posterior insular cortex. Furthermore, significant blood-oxygen-level-dependent signal increases emerged within the dorsal striatum, specifically involving the caudate nucleus and the putamen. In addition, the researchers observed pronounced responses in the thalamus, hippocampus, and parahippocampal gyrus during high-disgust presentations. Conversely, disgust sensitivity failed to modulate activity across these core emotional and interoceptive structures. Therefore, the findings demonstrate that dispositional reactivity, rather than secondary cognitive appraisal, dictates primary neural responsiveness to aversive visual triggers. Moreover, this clear anatomical separation confirms that affective vulnerability stems directly from hyper-reactive sensory-interoceptive processing centers. As a result, neuroscientists can now isolate the specific physiological pathways responsible for visceral emotional reactivity. Furthermore, these results indicate that therapeutic interventions must target bottom-up reactivity rather than solely addressing cognitive appraisal.

Insular-Striatal-Hippocampal Pathways Shape Subjective Experience

To examine how these interconnected brain regions coordinate subjective feelings, the research team performed advanced mediation and functional connectivity analyses. Notably, these computational models demonstrated that disgust propensity shapes subjective disgust experience through integrated insula-striatal-hippocampal pathways. First, the insular cortex functions as the principal neural hub for interoceptive awareness and visceral representation. When an individual encounters repulsive stimuli, the anterior insula registers physiological disturbances and converts visceral distress into conscious revulsion. Second, the striatum facilitates defensive avoidance behaviors and motor action selection. Because the caudate and putamen communicate continuously with the insula, these basal ganglia structures coordinate rapid behavioral withdrawal from pathogens. Third, the hippocampus and adjacent parahippocampal gyrus contribute contextual memory retrieval and associative learning. Consequently, when an individual with high disgust propensity views an offensive scene, hippocampal connections recall relevant aversive memories to amplify current distress. Together, these coordinated networks establish a synchronized functional circuit. Thus, subjective feelings of revulsion do not emerge from an isolated brain region. Instead, they arise from dynamic cross-talk between interoceptive, motivational, and mnemonic systems that respond intensely to perceived contamination.

Clinical Relevance for Obsessive-Compulsive and Anxiety Disorders

These neuroimaging discoveries carry profound clinical implications for psychiatry and clinical psychology, particularly in managing obsessive-compulsive disorder and related anxiety disorders. For example, contamination-based obsessive-compulsive disorder frequently responds poorly to standard pharmacotherapy and conventional exposure protocols. Historically, clinicians conceptualized contamination fears primarily as threat-based anxiety reactions. However, modern empirical evidence demonstrates that heightened disgust propensity drives persistent washing rituals and avoidance behaviors. In obsessive-compulsive disorder, patients experience overwhelming visceral disgust rather than purely anticipatory cognitive fear. Because the insula and striatal nodes display exaggerated baseline reactivity, benign environmental triggers evoke intolerable physical discomfort. Furthermore, similar neural abnormalities occur in specific phobias, including blood-injury-injection phobia and emetophobia. In these conditions, sudden insular hyper-reactivity triggers parasympathetic overactivation, severe nausea, and vasovagal presyncope. Similarly, eating disorders such as anorexia nervosa involve heightened disgust responses toward food cues. Therefore, recognizing disgust propensity as the central neurofunctional driver allows clinicians to refine diagnostic evaluations. Rather than treating all defensive avoidance as generalized anxiety, clinicians can specifically target visceral and somatosensory hypersensitivity. Consequently, assessing trait disgust enables clinicians to tailor personalized psychiatric treatment plans.

Translational Innovations in Neuromodulation and Behavioral Therapy

Delineating the insula-striatal-hippocampal network establishes a practical framework for developing targeted psychiatric interventions. Currently, traditional exposure and response prevention therapy relies heavily on habituation principles derived from fear conditioning models. Unfortunately, disgust experiences extinguish significantly more slowly than fear responses during routine exposure sessions. Consequently, patients with elevated disgust propensity frequently experience high relapse rates or premature treatment dropout. To overcome these therapeutic hurdles, behavioral therapists can implement specialized disgust counter-conditioning and cognitive defusion protocols. Specifically, counter-conditioning pairs repulsive triggers with positive appetitive stimuli to recalibrate striatal reward pathways. In addition, interoceptive exposure exercises can directly desensitize insular hyper-reactivity by teaching patients to tolerate visceral nausea sensations. Beyond behavioral therapies, interventional neuropsychiatry offers promising opportunities using non-invasive brain stimulation. For instance, clinicians can apply repetitive transcranial magnetic stimulation to modulate fronto-insular connectivity. By dampening excessive anterior insular activity, non-invasive neuromodulation could attenuate immediate visceral aversion. Ultimately, combining innovative behavioral techniques with targeted neurostimulation provides renewed optimism for individuals battling severe, treatment-resistant disgust pathology.

Frequently Asked Questions

What is the primary difference between disgust propensity and disgust sensitivity?

Disgust propensity reflects how frequently and intensely an individual experiences the primary emotion of disgust in response to repulsive triggers. In contrast, disgust sensitivity denotes the secondary negative appraisal, fear, or cognitive dread of experiencing disgust. Propensity drives immediate physiological arousal, whereas sensitivity governs subjective cognitive interpretation.

Which neural regions are activated by disgust propensity in this fMRI study?

The fMRI investigation revealed that disgust propensity significantly modulates neural activity across the anterior, middle, and posterior insular cortex. Additionally, elevated propensity activates the caudate, putamen, thalamus, hippocampus, and parahippocampal gyrus. These interconnected subcortical and paralimbic structures form a specialized neural circuit that directly mediates subjective disgust reactivity.

How do these neuroimaging results influence treatment for obsessive-compulsive disorder?

Contamination-based obsessive-compulsive disorder involves elevated disgust propensity, which habituates much more slowly than standard fear responses. Consequently, patients often exhibit poor responses to traditional exposure therapy. Recognizing insula-striatal hyper-reactivity allows clinicians to incorporate specialized disgust counter-conditioning, interoceptive exposure, and targeted non-invasive brain stimulation to modulate this stubborn defensive avoidance network.

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References

Gan X et al. Disgust Propensity, Not Disgust Sensitivity, Shapes the Reactivity of a Subjective Disgust Circuit in Humans. Hum Brain Mapp. 2026 Jun 01. doi: 10.1002/hbm.70577. PMID: 42237663.

Olatunji BO et al. Disgust in Anxiety and Obsessive-Compulsive Disorders: Recent Findings and Future Directions. Curr Psychiatry Rep. 2017;19(8):40. doi: 10.1007/s11920-017-0792-5.

Schippers AM et al. Enhanced disgust generalization in obsessive–compulsive disorder is related to insula and putamen hyperactivity. Psychol Med. 2025;55(6):1201-1212. doi: 10.1017/S003329172500054X.