Disgust helps humans avoid potentially pathogenic substances such as bodily effluvia. This reduces illness risks, and is difficult to overcome with cognitive strategies or even through simple habituation in the short term (minutes to hours). Whether habituation emerges in the long-term (months to years) is an unsolved question. Regular professional exposure to disgust elicitors is associated with lower disgust sensitivity and avoidance, but this could be due to selection and survivorship bias. Here, we avoid these limitations by testing a sample of parents (N=99) and controls (N=50) on self-report and behavioural avoidance measures. We used parent-specific items in disgust-sensitivity questionnaires, and child-related stimuli (soiled diapers) in a preferential-looking task. While the control group showed the expected behavioural avoidance, parents of children who were past the weaning stage showed almost no avoidance of stimuli depicting child-related or general bodily effluvia. Curiously, parents whose children had not been fully weaned showed similar disgust avoidance to the control group, even if they had older children who were weaned. These results suggest that parents habituate to disgust induced by faeces in diapers, and that this had generalised to other bodily effluvia. Contrary to our expectations, parents did show disgust avoidance while their (youngest) children were fed only milk, which could point to an adaptive response to reduce the risk of illness in young infants. In sum, continuous exposure to their children’s bodily effluvia inoculates parents to disgust for bodily effluvia, but only after the sensitive milk-feeding stage.

To address concerns about social media addiction, it is crucial to understand more about the young people who feel they are addicted. Here, in a preregistered study, we investigate the behavioural-emotional characteristics associated with self-reported social media addiction among UK adolescents (aged 16-18). We analyze the Millennium Cohort Study, a large, nationally-representative cohort dataset (n = 7,092), and find that almost half (47%) of adolescents report feeling addicted to social media. Compared to those who do not feel addicted, adolescents who feel addicted have higher extraversion and neuroticism, and lower self-reported self-control. Next, we explore behavioural-emotional heterogeneity within the group of adolescents who feel addicted. Employing a data-driven clustering method, we find three behavioural-emotional profiles associated with self-reported social media addiction. The first (representing 74% of those with self-reported addiction) is a ‘social’ profile, distinguished from others both with and without self-reported addiction by feelings of higher self-esteem and feeling safe and happy. The second (10% of those with self-reported addiction) is a ‘risk behaviour’ profile, with, compared with both those with and without self-reported addiction, more time spent on activities such as vaping, higher conduct problems and lower monitoring by parents. Finally, the third (16% of those with self-reported addiction) is a ‘low wellbeing’ profile, with higher depression and emotional difficulties, and lower self-esteem, than others both with and without self-reported addiction. Future research should disentangle the factors contributing to perceived addiction in each case, as well as investigating whether separate profiles respond differently to treatment approaches.

In common parlance, 'being in touch with your body' is often used positively. However, in a recent study, Banellis, Rebollo, and colleagues show that better stomach-brain synchronisation is actually associated with increased anxiety and depression scores. These findings add an interesting dimension to debates on the role of interoception in mental health.

Previous research has found pupil dilation associated with stimuli pre-assigned as positive and negative in their emotional valence; however, it is not yet clear how self-rated experiences of specific emotions may correlate with differences in pupil size. Using a novel methodology across two studies, 200 participants were presented with emotionally engaging images and sounds and then rated the extent to which they felt happy, sad, angry, fearful, and disgusted in response to these. Data were analyzed using linear mixed effects models to examine whether the participant's own emotion ratings predict pupil size. In 2 studies using standardized images and sounds, and varied 30-s audio clips, in trials with higher self-reported disgust and sadness there was a consistent relationship with pupil dilation. Disgust was most often the strongest predictor of pupil dilation. This effect emerged ∼2 s after stimulus onset and remained present throughout stimulus presentation. Happiness had a weaker effect on pupil dilation and fear was associated with a late pupillary response. Anger was associated with pupil constriction, but only in Study 2. The present approach finds the most consistent relationship between pupil dilation and self-rated disgust and sadness, compared to other negative emotions. The findings thus suggest that measures of pupil size warrant further investigation as a potential indicative psychophysiological correlate of self-reported emotions, with implications for distinguishing negative emotions, such as disgust from anger.

Gastrointestinal interoception is the sensing, interpretation and integration of signals originating from the gut. In contrast to chemosensory aspects of gut-brain signalling, perceptual aspects of gastrointestinal viscerosensation and visceromotor control have received relatively little attention despite clear links to physical and mental health and wellbeing. To facilitate research into these aspects of interoception, we developed a novel gastrointestinal sound discrimination task, Rumble Recognition, to measure gastrointestinal interoceptive accuracy, self-beliefs, and metacognitive insight in three ecologically valid conditions; following a 3 hour fast, after drinking sparkling water, and after consuming a high-protein meal replacement shake. The discrimination task used a two-interval forced choice design to assess gastrointestinal interoceptive performance accuracy alongside self-reported confidence from which a measure of metacognitive insight was computed. This novel task was tested for proof-of-principle in a healthy sample (n=45; 68% women), and demonstrated its feasibility, tolerability, and ability to yield parameters relevant naturalistic experiences including reported experience of hunger. The task is fully automated, requires minimal, affordable equipment, and written in freely available via open source code. We anticipate this task can facilitate research in this important, expanding and clinically relevant domain.

Understanding the mechanisms underlying complex behaviours--such as reading, decision-making, and human-animal interactions--requires theoretical frameworks that capture real-world complexity while remaining interpretable. While psychological and cognitive sciences seem well-positioned to provide such frameworks, they are facing a confidence crisis. A key issue is the lack of robust, precise theories capable of guiding research. To address this, it has been suggested that computational or mathematical models should be developed to formalise tentative theories. Mathematical psychology and computational modelling offer the necessary tools and competencies, yet they are often either too opaque for domain experts without computational expertise or too simplistic for complex behaviours, frequently focusing on toy examples or highly controlled tasks. Here, we present key insights from a workshop where interdisciplinary teams tackled the challenge of modeling the mechanisms underlying complex behaviours through case studies on reading comprehension, autism-related categorisation, negotiation, and human-wildlife conflict. Five key considerations emerged: (1) defining the problem, (2) forming and maintaining a team, (3) selecting the modelling approach(es), (4) implementing the model(s), and (5) making practical decisions and evaluating the model(s). These aspects are interdependent, each influencing the others. Addressing the challenge of modelling complex behaviour requires a community approach: fostering interdisciplinary collaboration, adopting transparent modelling practices, and embracing iterative refinement. By bridging theoretical and practical gaps, computational modelling can move beyond simplified problems to better capture real-world cognition and behaviour.

Background and Objectives A proposed strategy for attenuating the return of fear is conducting exposure therapy in multiple contexts (e.g., different locations), which is believed to enhance the generalizability of safety learning. Although conducting exposure in multiple contexts can be differentiated from conducting exposure with multiple stimuli, the two strategies are often conflated. Furthermore, researchers have not yet determined whether one of these strategies, or a combination thereof, is most effective in attenuating fear renewal. Methods Accordingly, the present treatment-analogue study examined the unique and combined effects of multiple-context and multiple-stimulus imagery-based exposure manipulations on threat expectancy, behavioral approach/anxiety, and attentional bias for threat over Zoom. Community adults (N=134) who met diagnostic criteria for snake phobia were randomized to exposure to a single snake in multiple environmental contexts (MC), exposure to multiple snakes in a single environmental context (MS), or exposure to multiple snakes in multiple environmental contexts (MS/MC). Results Results revealed significant reductions in threat expectancy and behavioral anxiety, but not attentional bias for threat in all three groups. However, behavioral approach declined over the course of exposure in the MS/MC condition but remained stable in the MC and MS conditions. There were no significant group differences in behavioral approach/anxiety or attentional bias at a one-week follow-up. However, participants in the MC condition reported lower threat expectancy at a one-week follow-up than the other groups and this group difference was partially mediated by lower mean distress during exposure. Conclusions Implications of these findings for the inhibitory retrieval theory are discussed.

Research has shown that some individuals do not benefit from exposure therapy and for those who do, fear can return. Occasional reinforcement, which involves intermittently reinforcing the feared outcome during exposure, and affect labeling, in which individuals describe their current affective state during exposure, are two inhibitory retrieval strategies that have shown promise for augmenting exposure interventions. Yet, it remains unclear whether these strategies differ in their efficacy for attenuating return of fear across multiple levels of analysis. Accordingly, the present treatment-analogue experiment examined the effects of a multi-session imagery-based exposure manipulation that included reminders of the feared outcome or prompts to label one’s affective experience in a phobic sample on threat expectancy, behavioral avoidance, and attentional bias for threat. Community adults ( N = 136) who met diagnostic criteria for snake phobia were randomized to a single-cue video exposure alone condition (S), a multiple-cue video exposure condition that occasionally reinforced the feared outcome (i.e., snake bite; FO), or a multiple-cue video exposure condition that instructed participants to label their affective response (AL). Results revealed significant reductions in threat expectancy and behavioral avoidance, but not attentional bias for threat, for all three groups. Although there were no significant group differences in threat expectancy and attentional bias for threat at a 1-week follow up, those in the FO condition completed significantly more BAT steps than the AL group and this group difference was partially mediated by distress variability and within-session fear reduction. The implications of these findings for the inhibitory retrieval theory are discussed.

Exposure therapy is an efficacious treatment for anxiety-related disorders. Yet, fear often returns after treatment. Occasional reinforcement, in which the feared stimulus is intermittently presented during extinction, increases safety learning and slows fear renewal in conditioning paradigms and analogue samples, but no studies to date have examined this strategy in clinical samples. The present study examined the effects of vicarious occasional reinforcement on fear renewal in a snake-phobic sample across multiple levels of analysis. Fear was intermittently reinforced by providing reminders of the feared outcome (a snake bite) throughout a two-session analogue video exposure manipulation. Snake-phobic adults were randomized to one of three conditions: a single-cue [S], multiple-cue [M], or multiple-cue+fear-outcome [M+FO] exposure group. Results showed the three groups did not significantly differ in threat expectancy or attentional bias for threat at follow-up. Despite sustained anxiety, however, the M+FO condition completed significantly more steps on a visual avoidance task at follow-up than the M and S conditions and heightened mean distress during exposure mediated this effect. The M and S groups did not significantly differ in visual avoidance at follow-up. These findings suggest incorporating reminders of the feared outcome into exposure may be an effective strategy for increasing inhibitory retrieval.

Orthorexia involves an obsessive tendency towards “healthy” foods. It is a risk factor for eating disorders ( anorexia nervosa and the proposed “ orthorexia nervosa ”) and psychological distress, but its biological mechanism remains unknown. We hypothesised that this mechanism operates through the stomach: increased gastric power differentiates appetising from unappetising foods, vagal stimulation reduces food liking, and gastric proto-nausea can be evoked by disgust; all contributors to disordered eating. We used electrogastrography alongside high-density facial landmark tracking to gauge responses to minimally processed (“healthy”), highly processed (“unhealthy”), and culturally unaccepted (“disgusting”) foods in a non-clinical sample (N=77). Trait orthorexia was associated with increased self-reported desire to eat healthy foods. Moreover, we found that higher orthorexia was associated with increasing disgust-related facial responses to unhealthy and disgusting foods. We then identified a relationship between food-healthiness ratings and gastric power: those who generally assigned lower healthiness ratings to foods showed higher gastric power for unhealthy than healthy foods, whereas those who expressed higher healthiness ratings showed higher gastric power for healthy over unhealthy foods. This suggests that the stomach tracks individual differences in eating preferences. Crucially, and contrary to our expectations, higher trait orthorexia was associated with a paradoxical increase in gastric power to unhealthy foods. One explanation is that higher gastric power for unhealthy foods reflects increased appetite for self-denied foods. Alternatively, orthorexia itself could be an adaptive response to exert stronger cognitive control over a pre-existing gastric appetite for unhealthy foods. ### Competing Interest Statement The authors have declared no competing interest. Medical Research Council, MC\_UU\_00030/12 Wellcome Trust, 226490/Z/22/Z

Homing pigeons (Columba livia) navigate by solar and magnetic compass, and fly home in idiosyncratic but stable routes when repeatedly released from the same location. However, when experienced pigeons fly alongside naive counterparts, their path is altered. Over several generations of turnover (pairs in which the most experienced individual is replaced with a naive one), pigeons show cumulative improvements in efficiency. Here, I show that such cumulative route improvements can occur in a much simpler system by using agent-based simulation. Artificial agents are in silico entities that navigate with a minimal cognitive architecture of goal-direction (they know roughly where the goal is), social proximity (they seek proximity to others and align headings), route memory (they recall landmarks with increasing precision), and continuity (they avoid erratic turns). Agents’ behaviour qualitatively matched that of pigeons, and quantitatively fitted to pigeon data. My results indicate that naive agents benefitted from being paired with experienced agents by following their previously established route. Importantly, experienced agents also benefitted from being paired with naive agents due to regression to the goal: naive agents were more likely to err towards the goal from the perspective of experienced agents’ memorised paths. This subtly biased pairs in the goal direction, resulting in intergenerational improvements of route efficiency. No cumulative improvements were evident in control studies in which agents’ goal-direction, social proximity, or memory were lesioned. These 3 factors are thus necessary and sufficient for cumulative route improvements to emerge, even in the absence of sophisticated communication or thought.

Countless workers handle bodily effluvia and body envelope violations every working day, and consequentially face deeply unpleasant levels of disgust. Understanding if and how they adapt can help inform policies to improve worker satisfaction and reduce staff turnover. So far, limited evidence exist that self-reported disgust is reduced (or lower to begin with) among those employed in high-disgust environments. However, it is unclear if this is due to demand effects or translates into real behavioural changes. Here, we tested healthcare assistants (N=32) employed in UK care homes and a control sample (N=50). We replicated reduced self-reported pathogen disgust sensitivity in healthcare workers compared to controls. We also found it negatively correlated with career duration, suggesting long-term habituation. Furthermore, we found that healthcare assistants showed no behavioural disgust avoidance on a web-based preferential looking task (equivalent to eye tracking). Surprisingly, this extended to disgust elicitors found outside care homes, suggesting generalisation of disgust habituation. While we found no difference between bodily effluvia (core disgust) and body envelope violations (gore disgust), generalisation did not extend to other domains: self-reported sexual and moral disgust sensitivity were not different between healthcare assistants and the control group, nor was there a correlation with career duration. In sum, our work confirms that people in high-frequency disgust employment are less sensitive to pathogen disgust. Crucially, we provide preliminary evidence that this is due to a process of long-term habituation with generalisation to disgust-elicitors within the pathogen domain, but not beyond it.

Disgust is a vital emotion in the avoidance of illness. Human adults across cultures show disgust towards sources of potential contamination or pathogens, and elect to avoid their ingestion or even to look at them. Stomach rhythms appear to play an important role: disgust reduces normogastric power, and the pharmacological normalisation of gastric state reduces disgust avoidance. Human children are remarkably slow to develop disgust as measured by self-report and facial expressions. Here, we investigate whether disgust-induced avoidance (measured using eye tracking) and changes in gastric rhythm (measured using electrogastrography) exist in children aged 5 to 13 years ( N = 45). We found that children in this bracket showed oculomotor avoidance of disgusting stimuli in a preferential-looking task, similar to adult samples in previous research. However, in contrast to adult samples in previous research, children did not show an attenuation in normogastric power. These findings could suggest that avoidance behaviour precedes gastric involvement during disgust. This would support the idea that children initially respond to parental modelling: parents set (and enforce) the social norm of disgust avoidance, and children initially conform and only later do they internalise disgust as an interoceptive signal. Alternatively, the employed stimuli could have been potent enough to induce oculomotor avoidance, but not a gastric response. Research is slim in this area, and future work should focus on elucidating the role of the stomach in disgust, and on longitudinal studies of disgust development from childhood to adolescence.

Audio-visual media possesses a remarkable ability to synchronise audiences' neural, behavioural, and physiological responses. This synchronisation is considered to reflect some dimension of collective attention or engagement with the stimulus. But what is it about these stimuli that drives such strong engagement? There are several properties of media stimuli which may lead to synchronous audience response: from low-level audio-visual features, to the story itself. Here, we present a study which separates low-level features from narrative by presenting participants with the same content but in separate modalities. In this way, the presentations shared no low-level features, but participants experienced the same narrative. We show that synchrony in participants' heart rate can be driven by the narrative information alone. We computed both visual and auditory perceptual saliency for the content and found that narrative was approximately 10 times as predictive of heart rate as low-level saliency, but that low-level audio-visual saliency has a small additive effect towards heart rate. Further, heart rate synchrony was related to a separate cohorts' continuous ratings of immersion, and that synchrony is likely to be higher at moments of increased narrative importance. Our findings demonstrate that high-level narrative dominates in the alignment of physiology across viewers.

Background: Efforts to identify risk and resilience factors for anxiety severity and course during the COVID-19 pandemic have focused primarily on demographic rather than psychological variables. Intolerance of uncertainty (IU), a transdiagnostic risk factor for anxiety, may be a particularly relevant vulnerability factor.Method: N = 641 adults with pre-pandemic anxiety reported their anxiety, intolerance of uncertainty, and other pandemic and mental health-related variables at least once and up to four times during the COVID-19 pandemic, with assessments beginning in Summer 2020 through Winter 2021. Analyses were preregistered on the Open Science Framework.Results: Higher intolerance of uncertainty at the first pandemic timepoint predicted more severe anxiety, but also a sharper decline in anxiety across timepoints. This finding was robust to the addition of pre-pandemic anxiety and demographic predictors as covariates. Younger age, lower self/parent education, and experience of COVID-19 illness at the first pandemic timepoint predicted more severe anxiety across timepoints, but did not predict anxiety trajectory.Conclusions: Differential levels of IU at the outset of the pandemic prospectively predicted more severe anxiety and a sharper decrease in anxiety over time. This finding was robust to the inclusion of covariates, including pre-pandemic anxiety and various demographic characteristics.