Dyadic body competence predicts movement synchrony during the mirror game.

The process of synchronizing our body movements with others is known to enhance rapport, affect, and prosociality. Furthermore, emerging evidence suggests that synchronizing activities may enhance cognitive performance. Unknown, by contrast, is the extent to which people's individual traits and experiences influence their ability to achieve and maintain movement synchrony with another person, which is key for unlocking the social and affective benefits of movement synchrony. Here, we take a dyad-centered approach to gain a deeper understanding of the role of embodiment in achieving and maintaining movement synchrony. Using existing data, we explored the relationship between body competence and body perception scores at the level of the dyad, and the dyad's movement synchrony and complexity while playing a 2.5-min movement mirroring game. The data revealed that dyadic body competence scores positively correlate with movement synchrony, but not complexity, and that dyadic body perception scores are not associated with movement synchrony or complexity. Movement synchrony was greater when the more experienced member of the dyad was responsible for copying movements. Finally, movement synchrony and complexity were stable across the duration of the mirror game. These findings show that movement synchrony is sensitive to the composition of the dyad involved, specifically the dyad's embodiment, illuminating the value of dyadic approaches to understanding body movements in social contexts.

Body part categorical matching in chimpanzees (Pan troglodytes).

Humans categorize body parts, reflecting our knowledge about bodies, and this could be useful in higher-level activities involving bodies. We tested whether humans' closest living relatives-chimpanzees-have the same ability using touchscreen tasks, focusing on the major parts: heads, torsos, arms, and legs. Six chimpanzees were trained to perform a body part matching-to-sample task using sets of pictures of chimpanzee bodies, where in each trial, the sample and choice pictures were the same. Five passed the training and received the test sessions, where three trial types were mixed: trained same-individual picture pairs; novel same-individual picture pairs; and novel different-individual picture pairs. All participants performed better than the chance level in all conditions and for all body parts. Further analyses showed differences in performance when the samples were different body parts. For example, the results revealed better performances for heads and torsos than arms and legs in "novel different-individual pairs". The study showed that chimpanzees can visually match and categorize body parts in this experiment setting, even across different chimpanzees' bodies, suggesting potential biological understanding. Different performances for body parts suggested a deviated categorization from humans. We hope this study will inspire future research on the evolution of body perception.

Natural scenes reveal diverse representations of 2D and 3D body pose in the human brain.

Human pose, defined as the spatial relationships between body parts, carries instrumental information supporting the understanding of motion and action of a person. A substantial body of previous work has identified cortical areas responsive to images of bodies and different body parts. However, the neural basis underlying the visual perception of body part relationships has received less attention. To broaden our understanding of body perception, we analyzed high-resolution fMRI responses to a wide range of poses from over 4,000 complex natural scenes. Using ground-truth annotations and an application of three-dimensional (3D) pose reconstruction algorithms, we compared similarity patterns of cortical activity with similarity patterns built from human pose models with different levels of depth availability and viewpoint dependency. Targeting the challenge of explaining variance in complex natural image responses with interpretable models, we achieved statistically significant correlations between pose models and cortical activity patterns (though performance levels are substantially lower than the noise ceiling). We found that the 3D view-independent pose model, compared with two-dimensional models, better captures the activation from distinct cortical areas, including the right posterior superior temporal sulcus (pSTS). These areas, together with other pose-selective regions in the LOTC, form a broader, distributed cortical network with greater view-tolerance in more anterior patches. We interpret these findings in light of the computational complexity of natural body images, the wide range of visual tasks supported by pose structures, and possible shared principles for view-invariant processing between articulated objects and ordinary, rigid objects.

Body awareness disturbances in patients with low back pain: a systematic review.

BACKGROUND: The pain-neuroscience literature has recently emphasized body perception or awareness. Impaired body perception results have been reported in many different chronic pain problems. Studies have reported that individuals with low back pain (LBP) also have body perception disturbances related to the lumbar spine. OBJECTIVES: This review aimed to determine the evidence that body awareness alterations in individuals with LBP. DESIGN: Systematic review. METHOD: Studies were searched in PubMed, Cochrane Library, and Pedro databases up to January 2021. Each database was searched independently, according to a specific iteration research string. The protocol record of the systematic review was entered into the PROSPERO system. RESULTS: Nine studies were included in this research. We found evidence to support more perceptual impairments in patients with LBP than healthy counterparts. In addition, the results of the studies showed an association between disrupted body awareness and pain severity, pain catastrophizing, and disability. CONCLUSIONS: Body perception disturbances in LBP seem to be a promising path that needs to be further explored, with the ultimate goal of developing treatment contents targeting body awareness as a more comprehensive and valid evaluation and therapeutic method. TRIAL REGISTRATION: The registration number was CRD42021235934.

Eating Disorders Risk Assessment and Body Esteem among Amateur and Professional Football Players.

BACKGROUND: The purpose of this study was to assess the risk of eating disorders and attitudes toward one's own body among football players at amateur and professional levels. METHODS: The study included 90 players from football clubs located in the Upper Silesia Metropolitan Area, participating in the 4th and 5th leagues in Poland. A survey questionnaire was used to conduct the study, which consisted of a metric section, an Eating Attitudes Test, and Body Esteem Scale questionnaires. The players were divided into two groups according to their sports level. RESULTS: Results showed that 24.4% of players were overweight, while 75.6% had a normative body weight. Approximately 16.7% met the criteria indicating susceptibility to an eating disorder. Body Esteem Scale interpretations revealed moderate body appraisal among players. CONCLUSIONS: Both amateur and professional athletes showed no significant difference in eating disorder risk, but professionals rated their bodies higher. Social media use, particularly on Twitter and Instagram, is correlated with eating disorders, with longer daily use associated with lower body ratings.

Smartphone Addiction and Related Factors among Athletes.

Smartphone addiction (SA) is increasing worldwide. The aim of this study is to determine the level of SA in athletes affiliated to the Turkish Handball Federation in Izmir and to examine its relationship with factors such as sociodemographic status, health status, eating attitude, and body perception. This cross-sectional study was conducted in March-April 2021 in Izmir Province. The sample of the study consisted of 212 licensed handball athletes. The short SA scale, three-factor nutrition scale, and body perception scale were used. A chi-square test was used for bivariate comparisons and logistic regression analysis was used for multivariate comparisons. The study was completed with 202 individuals (the coverage rate was 95.3%). The prevalence of SA was found to be 27.7%. The risk of SA increased 2.49-fold (CI: 1.17-5.31, p = 0.018) in female participants, 2.01-fold (CI: 1.01-4.06, p = 0.048) in participants with alcohol use, 2.17-fold (CI: 1.04-4.58, p = 0.042) in participants with low nutritional scores, 2.65-fold (CI: 1.15-6.10, p = 0.022) in individuals with high-income status, and 2.66-fold (CI: 1.07-6.64, p = 0.036) in individuals with high body perception scale score. In total, 27.7% of the athlete sample had scores above the SA threshold. These results point out that a behavioral addiction such as SA can occur even in professionals of an activity such as sports, known for beneficial effects in terms of healthy life.

Changes in younger stroke survivors' body perception as indicated in body drawings: A comparison between Expressive Arts-based Intervention and control groups.

Stroke-related deficits affect stroke survivors' perception of their bodies and possibly impede their progress in rehabilitation and well-being. This study adopted a pre-and post-test design to compare the changes in body perception among younger stroke survivors after participating in an 8-week Expressive Arts-based Intervention (EABI) (n = 32) with the control group (n = 30). Each participant partook in structured drawing interviews at baseline (T0) and 8-week follow-up/post-intervention (T1). The data were analyzed using content analysis. More EABI (n = 27) than control (n = 14) participants reported positive changes in body perception and applied lighter colours or created a more symmetrical drawing at T1. They shared that EABI promoted these positive changes by facilitating the reconnection with one's body and self. While some control participants experienced positive changes in body perception, others tended to apply darker colours or the same colour to show negative or no changes in body perception. More control (n = 8) than EABI (n = 3) participants reported negative thoughts about their bodies and negative influences from other individuals and the environment. The findings suggested that EABI can change stroke survivors' body perception. EABI can be considered one of the interventions that may help foster positive changes in body perception.

Transgender body image: Weight dissatisfaction, objectification & identity - Complex interplay explored via matched group / Imagen corporal transgénero: insatisfacción con el peso, cosificación e identidad: interacción compleja explorada a través de un grupo emparejado

In the context of body image and mental health, transgender individuals face distinctive challenges stemming from the complexities of their gender identity journey, societal expectations, and body norms. However, the existing line of research on this topic remains limited. This study explores the complex relationship in transgender individuals between body objectification, body weight dissatisfaction, and eating concerns. A sample of 154 individuals (77 transgenders paired with 77 cisgenders) was recruited via LGBTQ+ groups’ mailing lists. Participants completed various questionnaires assessing body image, eating psychopathology, depression, and body objectification. Propensity score matching was performed with different variables: age, current BMI, years of education, current self-identified gender, and sexual orientation. The results revealed that transgender individuals experienced higher levels of body objectification, body weight dissatisfaction, and eating concerns compared to their cisgender counterparts. Additionally, age emerged as a protective factor, as older transgender individuals demonstrated improved body acceptance and self-esteem. Logistic regression analyzes indicated that bulimic behaviors, depressive symptoms, and appearance control beliefs were specific factors significantly associated with being transgender. Our findings highlight the unique challenges faced by transgender individuals in navigating their gender identity and body image, underscoring the importance of targeted interventions and support systems.(AU)

Validation of the Italian version of the Neuroception of Psychological Safety Scale (NPSS).

Research on the neuroscience of fear in both humans and non-humans has suggested that a lack of acquisition of safety cues might be a biological hallmark of posttraumatic stress disorder (PTSD). Danger perception, and in particular, feeling as one's own life is in danger, is thought to represent a major predictor of PTSD. Persistent danger perception is concurrently associated with a persistence of lack of safety. However, despite several research efforts, no validated psychometric tools exist regarding psychological safety as a unique core construct in the domain of a soothing-contentment system. By including social, compassionate, and bodily components, the Neuroception of Psychological Safety Scale (NPSS), neurophysiologically rooted in the polyvagal theory, aims to specifically assess psychological safety. Originally developed in English, we employed a rather large non clinical sample to validate our Italian translation of the NPSS (n = 338) and the scale was found to retain a three-factor structure. In light of its positive moderate correlations with the Unconditional Self-Kindness Scale (ρ = 0.376) and the Self-Compassion Scale-Short-Form (ρ = 0.481), good convergent validity and robust psychometric properties were shown by the NPSS. The Subjective Traumatic Outlook Questionnaire (ρ = -0.283) and the three subscales of the Body Perception Questionnaire-22-Body Awareness (ρ = -0.103), Supradiaphragmatic Reactivity (ρ = -0.234), and Body Awareness/Subdiaphragmatic Reactivity (ρ = -0.146)-were found to have weak negative correlations with the NPSS, which further demonstrated its good discriminant validity. Eventually, the NPSS was found to show good test-retest reliability (intraclass correlation coefficient = 0.922; three-week time interval), and its usage is fostered in clinical and research contexts where the evaluation of psychological safety is of relevance.

Assessment on interoceptive awareness on alcohol use and gambling disorders reveals dissociable interoceptive abilities linked to external and internal dependencies: Practical use of Body Perception Questionnaire Very Short Form (BPQ-VSF) in clinical settings.

Interoception is one of the pivotal cognitive functions for mechanisms of our body awareness, and malfunction of the interoceptive network is thought to be associated with mental illness, including addiction. Within addictive disorders, substance-based and non-substance-based addictions are known to hold dissociable reward systems. However, little is known about how interoceptive awareness between these addiction sub-types would differ. Subjective interoceptive awareness was assessed among patients with alcohol use disorder (n = 50) who were subsequently hospitalized or remained out-patient and gambling addiction (n = 41) by the Body Awareness component of the Japanese version of the Body Perception Questionnaire (BPQ-VSFBA-J) and compared them against healthy control (n = 809). Both addiction groups showed significantly lower BPQ than the control, with no substantial differences between inpatients and outpatients for alcohol samples. Notably, BPQ scores for gambling patients were significantly lower than those for the alcohol group. This evidence may suggest a putative role of interoceptive ability on the severity of behavioral addiction over substance-based addiction.

The experience of bearing a child: implications on body boundaries and their link to preterm birth.

BACKGROUND: Preterm birth, which occurs when a baby is born before 37 weeks, has enormous implications for public health. It is the leading cause of infant death and mortality in children under the age of five. Unfortunately, the multifaceted causes of preterm birth are not fully understood. One construct that has received increasing attention in women's transition to motherhood is body boundaries, i.e., the metaphorical barriers that separate the self from the outer, surrounding "not self." This study aims to examine the role of well-defined and disturbed body boundaries in predicting preterm birth. METHODS: A sample of 655 Israeli pregnant women reported their sense of body boundaries (BBS, as measured by the Sense of Body Boundaries Survey) pre- and postnatally. We performed a General Linear Model (GLM) testing the effect of the BBS total score on the days women delivered before their due date and controlling for whether it was the women's first child. RESULTS: Our GLMs controlling for whether it was the women's first child showed that the BBS total mean exhibited a significant predictive effect on the number of days delivered before the due date (F(57,313) = 3.65, p < .001). CONCLUSIONS: These results demonstrate heterogeneity in women's sense of body boundaries during pregnancy and are the first to disentangle a link between disturbed body boundaries and preterm birth. Mediating mechanisms in this relation, e.g., psychosocial stress, as well as clinical implications are discussed in detail.

Transgender body image: Weight dissatisfaction, objectification & identity - Complex interplay explored via matched group.

In the context of body image and mental health, transgender individuals face distinctive challenges stemming from the complexities of their gender identity journey, societal expectations, and body norms. However, the existing line of research on this topic remains limited. This study explores the complex relationship in transgender individuals between body objectification, body weight dissatisfaction, and eating concerns. A sample of 154 individuals (77 transgenders paired with 77 cisgenders) was recruited via LGBTQ+ groups' mailing lists. Participants completed various questionnaires assessing body image, eating psychopathology, depression, and body objectification. Propensity score matching was performed with different variables: age, current BMI, years of education, current self-identified gender, and sexual orientation. The results revealed that transgender individuals experienced higher levels of body objectification, body weight dissatisfaction, and eating concerns compared to their cisgender counterparts. Additionally, age emerged as a protective factor, as older transgender individuals demonstrated improved body acceptance and self-esteem. Logistic regression analyzes indicated that bulimic behaviors, depressive symptoms, and appearance control beliefs were specific factors significantly associated with being transgender. Our findings highlight the unique challenges faced by transgender individuals in navigating their gender identity and body image, underscoring the importance of targeted interventions and support systems.

Converging evidence that left extrastriate body area supports visual sensitivity to social interactions.

Navigating our complex social world requires processing the interactions we observe. Recent psychophysical and neuroimaging studies provide parallel evidence that the human visual system may be attuned to efficiently perceive dyadic interactions. This work implies, but has not yet demonstrated, that activity in body-selective cortical regions causally supports efficient visual perception of interactions. We adopt a multi-method approach to close this important gap. First, using a large fMRI dataset (n = 92), we found that the left hemisphere extrastriate body area (EBA) responds more to face-to-face than non-facing dyads. Second, we replicated a behavioral marker of visual sensitivity to interactions: categorization of facing dyads is more impaired by inversion than non-facing dyads. Third, in a pre-registered experiment, we used fMRI-guided transcranial magnetic stimulation to show that online stimulation of the left EBA, but not a nearby control region, abolishes this selective inversion effect. Activity in left EBA, thus, causally supports the efficient perception of social interactions.

Interoception: Where do we go from here?

In recent years, there has been a significant rise in interest in interoception, the processing of internal bodily signals. This interest has been coupled by increased concerns regarding the measurement and conceptualisation of interoception. Focusing on cardiac interoceptive accuracy, I outline what I believe to be the most pressing issues in the field of interoception-specifically the continued reliance on the heartbeat counting task. I then provide an overview of what I believe to be more general limitations concerning how we measure and conceptualise individual differences in interoception and suggestions for a way forward. Specifically, I believe that by moving beyond single measurements, establishing optimal levels of interoceptive accuracy, and refocusing from accuracy to propensity, we may be able to uncover the real-life relevance of interoceptive abilities.

Did you skip leg day? The neural mechanisms of muscle perception for body parts.

While the neural mechanisms underpinning the perception of muscularity are poorly understood, recent progress has been made using the psychophysical technique of visual adaptation. Prolonged visual exposure to high (low) muscularity bodies causes subsequently viewed bodies to appear less (more) muscular, revealing a recalibration of the neural populations encoding muscularity. Here, we use visual adaptation to further elucidate the tuning properties of the neural processes underpinning muscle perception for the upper and lower halves of the body. Participants manipulated the apparent muscularity of upper and lower bodies until they appeared 'normal', prior to and following exposure to a series of top/bottom halves of bodies that were either high or low in muscularity. In Experiment 1, participants were adapted to isolated own-gender body halves from one of four conditions; increased (muscularity) upper (body half), increased lower, decreased upper, or decreased lower. Despite the presence of muscle aftereffects when the body halves the participants viewed and manipulated were congruent, there was only weak evidence of muscle aftereffect transfer between the upper and lower halves of the body. Aftereffects were significantly weaker when body halves were incongruent, implying minimal overlap in the neural mechanisms encoding muscularity for body half. Experiment 2 examined the generalisability of Experiment 1's findings in a more ecologically valid context using whole-body stimuli, producing a similar pattern of results as Experiment 1, but with no evidence of cross-adaptation. Taken together, the findings are most consistent with muscle-encoding neural populations that are body-half selective. As visual adaptation has been implicated in cases of body size and shape misperception, the present study furthers our current understanding of how these perceptual inaccuracies, particularly those involving muscularity, are developed, maintained, and may potentially be treated.

Before-and-After Photography on Social Media: The Pursuit of Impossible Beauty.

Plastic surgeons and aesthetic medicine professionals often share "before" and "after" clinical cases on social media, but this practice can lead to unintended consequences, such as dysmorphophobia and unrealistic expectations. These before-and-after images, frequently posted on social media, tend to promote unreachable, sometimes retouched, beauty standards, downplaying the complexities of the surgical process, omitting details about postoperative care, recovery, and potential complications. This can create the illusion that perfection is easily attainable through surgery, fostering unrealistic ideals and negatively impacting viewers' self-image and self-worth. Dysmorphophobia, characterized by an excessive preoccupation with perceived flaws in one's appearance, is closely linked to social media usage, especially among Caucasian women. Plastic surgeons hold the responsibility to provide honest insights into cosmetic procedures on social media, emphasizing the healing process, potential risks, and limitations. Celebrating diversity in appearance and sharing genuine patient stories can combat idealized beauty standards and reduce the stigma surrounding cosmetic surgery. They must prioritize honesty, provide comprehensive context for their images, and promote a broader view of beauty that includes mental health and individual diversity. Their ethical responsibility extends beyond the operating room and should guide all aspects of their professional practice.Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Aesthetic preference in the production of image sequences.

Introduction: This research uses the production method to study aesthetic preference for sequences of human body postures. In two experiments, participants produced image sequences based on their aesthetic preferences, while we measured the visual aesthetic features displayed in the compositions. Methods: In Experiment 1, participants created static image sequences based on their preferences. In Experiment 2, participants sorted images into apparent motion sequences they preferred to view. Results: In Experiment 1, good continuation of successive bodies and body-like objects was the preferred order. In Experiment 2, participants preferred abstract images with local sequential symmetry and human body postures exhibiting global sequential symmetry. Discussion: Our findings are compared to those of previous studies that employed the more widely used method of choice. Our experiments propose novel methods and conceptualizations for investigating aesthetic preferences for human body movement and other types of stimulus sequences.

A scoping review and index of body stimuli in psychological science.

Naturalistic body stimuli are necessary for understanding many aspects of human psychology, yet there are no centralized databases of body stimuli. Furthermore, there are a high number of independently developed stimulus sets lacking in standardization and reproducibility potential, and a general lack of organization, contributing to issues of both replicability and generalizability in body-related research. We conducted a comprehensive scoping review to index and explore existing naturalistic whole-body stimuli. Our research questions were as follows: (1) What sets of naturalistic human whole-body stimuli are present in the literature? And (2) On what factors (e.g., demographics, emotion expression) do these stimuli vary? To be included, stimulus sets had to (1) include human bodies as stimuli; (2) be photographs, videos, or other depictions of real human bodies (not computer generated, drawn, etc.); (3) include the whole body (defined as torso, arms, and legs); and (4) could include edited images, but still had to be recognizable as human bodies. We identified a relatively large number of existing stimulus sets (N = 79) which offered relative variability in terms of main manipulated factors and the degree of visual information included (i.e., inclusion of heads and/or faces). However, stimulus sets were demographically homogenous, skewed towards White, young adult, and female bodies. We identified significant issues in reporting and availability practices, posing a challenge to the generalizability, reliability, and reproducibility of body-related research. Accordingly, we urge researchers to adopt transparent and accessible practices and to take steps to diversify body stimuli.

Body Image Perceptions and Visualization of Vietnamese Men Who Have Sex with Men (MSM).

Research on body image among men who have sex with men (MSM) has predominantly been approached with the assumption that all MSM conform to a culturally preferred body, and have a high risk of body image concerns leading to risky behaviors and negative health outcomes. Scholars have called for a more nuanced understanding of how MSM engage with their body images. In response, we conducted 30 semi-structured interviews with Vietnamese MSM to explore their perceptions and feelings of their bodies, including their current body, idealized body, and sexually desired body. Inductive thematic analysis was utilized. The findings highlight the diversity and complexity in Vietnamese MSM's perceptions and feelings about their bodies, which Western measurements of body image and body dissatisfaction might not fully capture. The participants also acknowledge the pressure of physical appearance; however, they do not always conform to the dominant body ideals and have a high risk of body dissatisfaction. We conclude with a call for reframing the approach to gay and bisexual men's body image to understand better how they navigate complex pressures and make sense of their body image instead of assuming they are at risk of body dissatisfaction.