Novel online enfacement illusion for investigating self-perception in mental disorders: an experimental study protocol.

BACKGROUND: Remote research methods and interventions for mental health disorders have become increasingly important, particularly for conditions like eating disorders (EDs). Embodiment illusions, which induce feelings of ownership over another person?s body or body parts, offer valuable insights into the mechanisms underlying self-perception issues in EDs and potential interventions. However, existing research using these illusions has been limited to face-to-face settings. We illustrate a novel online protocol to induce the enfacement illusion (embodiment illusion principles applied to one's face) in an ED-based sample. METHODS: Participants complete a 2-hr virtual session with a researcher. First, baseline trait/state ED psychopathology measures and a self-face recognition task occur. Second, participants experience two testing blocks of the enfacement illusion involving synchronously and asynchronously mimicking a pre-recorded actor's facial expressions. After each block, subjective and objective enfacement illusion measures occur alongside state ED psychopathology reassessment. DISCUSSION: Successfully inducing enfacement illusions online could provide an affordable, accessible virtual approach to further elucidate the mechanistic role of self-perception disturbances across psychopathologies such as EDs. Moreover, this protocol may represent an innovative, remotely-delivered intervention strategy, as 'enfacement' over another face could update negative self-representations in a cost-effective, scalable manner.

Enfacement illusions: Filling a knowledge gap in eating disorder risk assessment, prevention, and intervention?

Body image disturbance (BID) is central to eating disorders (EDs), yet the role of self-face perception has received limited empirical attention despite rising sociocultural pressures emphasizing facial appearance through technologies such as social media. Emerging evidence suggests impairments in self-face recognition accuracy and distorted perceptions of facial appearance among individuals with EDs. Enfacement illusions, involving the experimental induction of perceived ownership over another's face, offer a novel paradigm to comprehensively investigate the perceptual multisensory integration processes underlying self-face perception disturbances in ED populations. Such an approach may hold promise for elucidating core pathological mechanisms contributing to BID and ED psychopathology. We discuss how rigorous investigation of self-face perception through the enfacement illusion paradigm represents an innovative direction of research and/or clinical application that may advance etiological models of EDs and possibly inform interventions targeting the potentially multidimensional nature of body and facial image disturbances characterizing EDs. PUBLIC SIGNIFICANCE STATEMENT: Body image disturbance is central to eating disorders (EDs), yet, the role of face-related disturbances remains critically under-investigated. After summarizing findings on face-related disturbances in EDs we propose how enfacement illusions (i.e., the experimental induction of ownership over another's face) may elucidate self-face perception disturbances in EDs, and their underlying mechanisms. Enfacement illusions may also offer an intervention to potentially address multifaceted face and body image disturbances characterizing EDs.

Effects of videoconferencing use on momentary changes in disordered eating urges, body dissatisfaction, and mood.

The coronavirus disease 2019 (COVID-19) pandemic led to a global surge in videoconferencing use for work/study-related reasons. Although these platforms heighten exposure to one's image, the implications of videoconferencing use on body image and eating concerns remain scantly examined. This study sought to investigate, in an Australian sample, whether videoconferencing for work/study-related reasons predicted increases in body dissatisfaction (BD), urge to engage in disordered eating (DE; restrictive eating, exercise, overeating/purging), and negative mood at the state level. Participants (N = 482, 78.8% women, Mage  = 20.5 years [SD = 5.3]) completed baseline demographic measures, accompanied by an ecological momentary assessment (EMA) of videoconferencing for work/study-related reasons, BD, DE urges, and negative mood six times a day for 7 days via a smartphone application. Most participants (n = 429; 89.0%) reported state-based videoconferencing use during the EMA phase. Consistent with expectations, state-based videoconferencing use was associated with an increase in state-level urges to engage in exercise. However, contrary to predictions, state-based videoconferencing use was linked to a decrease in state-level BD at the next assessment point and failed to predict negative mood and urges to engage in restrictive eating or overeating/purging at the state level. Given the simplified measure of videoconferencing use, the current research is considered preliminary and future replication and extension, using more nuanced measures, is warranted.

Embodiment illusions and eating disorders: snapshot of implications for research and interventions.

In recent years, researchers have increasingly used the embodiment illusion paradigm in subclinical and clinical eating disorder (ED) populations. This has important implications for understanding and ultimately improving bodily misperception. Here, we provide a brief overview of the current 'state of the art' of these implications while highlighting challenges and future directions.

Do appearance comparisons mediate the effects of thinspiration and fitspiration on body dissatisfaction, happiness, and disordered eating urges in women's daily lives?

We examined whether thinspo and fitspo exposure predicted women's body dissatisfaction (BD), happiness, and disordered eating (DE) urges (binge-eating/purging, restrictive eating, and exercise) in daily life. A further aim was to assess whether these effects were stronger for thinspo versus fitspo exposure and whether upward appearance comparisons mediated the effect of thinspo-fitspo exposure on BD, happiness, and DE urges. Participants (N = 380 women) completed baseline measures and a 7-day ecological momentary assessment (EMA) investigating state-based experiences of thinspo-fitspo exposure, appearance comparisons, BD, happiness, and DE urges. Multilevel analyses revealed that thinspo-fitspo exposure was associated with greater BD and DE urges (but unrelated to happiness) at the same EMA time point. However, there was no association between thinspo-fitspo exposure and BD, happiness, and DE urges at the next EMA time-point. Thinspo relative to fitspo exposure was associated with greater BD (but unrelated to happiness and DE urges) at the same EMA time-point. The proposed mediation models were not supported in time-lagged analyses; such that upward appearance comparisons did not mediate the effects of thinspo-fitspo exposure on BD, happiness, and DE urges. Current findings provide novel micro-longitudinal data on the potentially direct detrimental effects of thinspo-fitspo exposure on women's daily lives.

Tonight, I'm disordered eating: The effects of food delivery app use, loneliness, and mood on daily body dissatisfaction and disordered eating urges.

With the recent proliferation of food delivery applications ('apps'; FDAs), accessing a meal is more convenient and immediate than ever. However, these apps may foster dysregulated eating behaviours, including maladaptive eating to cope with negative emotional states. Using ecological momentary assessment (EMA), the current study assessed whether FDA use at baseline predicted levels of EMA-assessed disordered eating urges and body dissatisfaction, whether negative mood and loneliness impacted disordered eating urges and body dissatisfaction at the state level, and whether the latter relationships were moderated by FDA usage frequency. Participants (N = 483; 78.7% women; 20.1% men; 1.2% other) completed a baseline questionnaire and were characterised as current FDA users (49.3%) or non-users (50.7%). Participants then completed a smartphone-facilitated investigation into their experiences of loneliness, negative mood, body dissatisfaction, and disordered eating urges, six times per day for 7-days. Across the entire sample, current FDA users at baseline reported greater EMA-assessed urges to overeat. At the state level, loneliness and negative mood predicted greater body dissatisfaction, with the latter also predicting greater urges for restrictive eating and overeating. Among current FDA users at baseline, at the state level, loneliness predicted greater body dissatisfaction, and negative mood predicted greater body dissatisfaction and urges for overeating. No moderating effects were observed for baseline FDA usage frequency. These results elucidate FDA use and daily experiences of loneliness and negative mood as factors elevating eating disorder (ED)-related risk. Further extensions of this research with nuanced measures of state FDA use are required.

The Effects of Appearance-Based Comments and Non-Appearance-Based Evaluations on Body Dissatisfaction and Disordered Eating Urges: An Ecological Momentary Assessment Study.

The current study used ecological momentary assessment (EMA) to investigate whether appearance-based comments, social and performance-based evaluations affected levels of body dissatisfaction (BD) and urges to engage in disordered eating behaviors (DE) throughout daily life. A total of 620 participants completed a baseline questionnaire assessing sociodemographic variables. Participants then downloaded a mobile app which alerted them to complete short surveys assessing their levels of BD, DE urges, and experiences of receiving comments and evaluations six times per day for 7 days. Negative appearance-based comments predicted greater levels of state BD, while positive appearance comments predicted lower levels of state BD. Negative social and performance-based evaluations predicted an increase in state BD, while positive evaluations predicted a decrease in this outcome variable. No significant predictor was found for the DE urge outcomes. The present findings suggest that receiving negative and positive feedback in various domains of one's life may predict opposite outcomes for body image. However, these effects do not necessarily associate with urges to engage in DE in a nonclinical population.

Mirror, mirror, on the wall: During pandemics, how can self-perception research in people with eating disorders happen at all?

BACKGROUND: 'Classic' embodiment illusions (e.g., the feeling of owning another person's hand) involves a three-way interaction between visual, proprioceptive, and tactile stimuli. These illusions have been studied in eating disorder (ED) populations given the potential implications for better understanding and improving body image concerns. Recently, several studies have employed 'tactile-reduced' methods mainly relying on the integration of visual and proprioceptive information to induce embodiment illusions in non-ED populations. To date, there has been no substantial review of these tactile-reduced approaches to consider their potential research and clinical utility in ED populations. METHOD: This review sought to examine and integrate studies across three areas. Firstly, those that employed tactile-reduced embodiment techniques in non-ED populations. Secondly, those that used classic embodiment techniques to compare whether ED and non-ED populations differ in their susceptibility to embodiment. Thirdly, studies that investigated whether experiencing classic or tactile-reduced embodiment techniques can improve image-related concerns. RESULTS: For the first aim five studies were identified, all of which found that tactile-reduced methods consistently induced embodiment illusions in non-ED individuals. For the second aim, seven studies comparing ED and non-ED samples were found. ED patients were more susceptible to embodiment than non-ED samples in four studies, less susceptible in one study, and equally susceptible in two studies. Finally, for aim three, amongst the seven studies that used classic or tactile-reduced embodiment methods in ED populations, six reported improvements in self-perception (i.e., reduced body size overestimation, decreased body dissatisfaction and fear of gaining weight). CONCLUSIONS: Along with the classic approach, tactile-reduced embodiment approaches have implications for ED research and clinical practice, particularly for situations when face-to-face contact with people are restricted. Suggestions are provided for future researchers who wish to ensure best practice for planning embodiment research involving classic and tactile-reduced approaches.

Embodiment illusions involve the temporary experience of owning another person's body or body parts. These illusions have been studied in people with eating disorders (EDs) as a means for (i) better understanding their self-perception issues (e.g., they tend to see their own appearance as being too big), and (ii) improving these self-perception issues (i.e., does experiencing embodiment reduce distortions involving body size?). 'Classic' embodiment illusions typically require participants to simultaneously experience visual, proprioceptive, and tactile sensory stimulation. However, COVID -19 pandemic restrictions have limited research in face-to-face settings which poses a challenge for the classic approach, mainly in relation to tactile input which would usually be provided by a researcher. A 'tactile-reduced' approach for eliciting embodiment illusions would, therefore, enable this field of research to continue, which in turn may benefit people with EDs. While several studies in non-clinical populations have demonstrated the effectiveness of a tactile-reduced approach, understanding surrounding this approach in ED populations is lacking. In this review, we offer a prospective set of suggestions regarding how tactile-reduced embodiment may be conducted with ED populations, both in terms of better understanding their (problematic) self-perception, and how such concerns may be improved.

Love me Tinder: The effects of women's lifetime dating app use on daily body dissatisfaction, disordered eating urges, and negative mood.

Dating apps may potentially serve as an environment that subjects young women to the harmful effects of appearance-related pressure. The current study assessed for the first time whether women's dating app use predicted body dissatisfaction (BD), urges to engage in disordered eating (DE), and negative mood in daily life. We also examined the unique effects of women's dating app partner preferences (i.e., seeking idealised versus non-idealised physical characteristics) on the aforementioned outcomes, and whether appearance-based rejection sensitivity (appearance-RS) moderated the effects of dating app use. Participants (N = 296; 100% women) first completed a baseline survey assessing lifetime dating app usage (i.e., current or former usage), partner preferences, and appearance-RS, followed by a 7-day smartphone-facilitated ecological investigation into momentary experiences of BD, DE urges (i.e., binge-eating/purging, dietary restraint, and exercise), and negative mood. Ninety-four women (32%) reported lifetime dating app usage, which, relative to non-use, predicted greater daily urges for binge-eating/purging and negative mood. However, appearance-RS failed to moderate these effects. Among dating app users, partner preferences were not a significant predictor of the central outcomes. These findings extend previous research by examining the unique effects of dating app use on everyday BD, DE urges, and negative mood. Replication and extension are encouraged.