Neural Control of Sexually Dimorphic Social Behavior: Connecting Development to Adulthood.

Rapid advances in the neural control of social behavior highlight the role of interconnected nodes engaged in differential information processing to generate behavior. Many innate social behaviors are essential to reproductive fitness and therefore fundamentally different in males and females. Programming these differences occurs early in development in mammals, following gonadal differentiation and copious androgen production by the fetal testis during a critical period. Early-life programming of social behavior and its adult manifestation are separate but yoked processes, yet how they are linked is unknown. This review seeks to highlight that gap by identifying four core mechanisms (epigenetics, cell death, circuit formation, and adult hormonal modulation) that could connect developmental changes to the adult behaviors of mating and aggression. We further propose that a unique social behavior, adolescent play, bridges the preweaning to the postpubertal brain by engaging the same neural networks underpinning adult reproductive and aggressive behaviors.

Plasmacytoid Dendritic Cells: Development, Regulation, and Function.

Plasmacytoid dendritic cells (pDCs) are a unique sentinel cell type that can detect pathogen-derived nucleic acids and respond with rapid and massive production of type I interferon. This review summarizes our current understanding of pDC biology, including transcriptional regulation, heterogeneity, role in antiviral immune responses, and involvement in immune pathology, particularly in autoimmune diseases, immunodeficiency, and cancer. We also highlight the remaining gaps in our knowledge and important questions for the field, such as the molecular basis of unique interferon-producing capacity of pDCs. A better understanding of cell type-specific positive and negative control of pDC function should pave the way for translational applications focused on this immune cell type.

Juvenile social play predicts adult reproductive success in male bottlenose dolphins.

For over a century, the evolution of animal play has sparked scientific curiosity. The prevalence of social play in juvenile mammals suggests that play is a beneficial behavior, potentially contributing to individual fitness. Yet evidence from wild animals supporting the long-hypothesized link between juvenile social play, adult behavior, and fitness remains limited. In Western Australia, adult male bottlenose dolphins (Tursiops aduncus) form multilevel alliances that are crucial for their reproductive success. A key adult mating behavior involves allied males using joint action to herd individual females. Juveniles of both sexes invest significant time in play that resembles adult herding-taking turns in mature male (actor) and female (receiver) roles. Using a 32-y dataset of individual-level association patterns, paternity success, and behavioral observations, we show that juvenile males with stronger social bonds are significantly more likely to engage in joint action when play-herding in actor roles. Juvenile males also monopolized the actor role and produced an adult male herding vocalization ("pops") when playing with females. Notably, males who spent more time playing in the actor role as juveniles achieved more paternities as adults. These findings not only reveal that play behavior provides male dolphins with mating skill practice years before they sexually mature but also demonstrate in a wild animal population that juvenile social play predicts adult reproductive success.

Opportunities for risk-taking during play alters cognitive performance and prefrontal inhibitory signalling in rats of both sexes.

Social play behaviour is a rewarding activity that can entail risks, thus allowing young individuals to test the limits of their capacities and to train their cognitive and emotional adaptability to challenges. Here, we tested in rats how opportunities for risk-taking during play affect the development of cognitive and emotional capacities and medial prefrontal cortex (mPFC) function, a brain structure important for risk-based decision making. Male and female rats were housed socially or social play-deprived (SPD) between postnatal day (P)21 and P42. During this period, half of both groups were daily exposed to a high-risk play environment. Around P85, all rats were tested for cognitive performance and emotional behaviour after which inhibitory currents were recorded in layer 5 pyramidal neurons in mPFC slices. We show that playing in a high-risk environment altered cognitive flexibility in both sexes and improved behavioural inhibition in males. High-risk play altered anxiety-like behaviour in the elevated plus maze in males and in the open field in females, respectively. SPD affected cognitive flexibility in both sexes and decreased anxiety-like behaviour in the elevated plus maze in females. We found that synaptic inhibitory currents in the mPFC were increased in male, but not female, rats after high-risk play, while SPD lowered prefrontal cortex (PFC) synaptic inhibition in both sexes. Together, our data show that exposure to risks during play affects the development of cognition, emotional behaviour and inhibition in the mPFC. Furthermore, our study suggests that the opportunity to take risks during play cannot substitute for social play behaviour.

Spontaneous playful teasing in four great ape species.

Joking draws on complex cognitive abilities: understanding social norms, theory of mind, anticipating others' responses and appreciating the violation of others' expectations. Playful teasing, which is present in preverbal infants, shares many of these cognitive features. There is some evidence that great apes can tease in structurally similar ways, but no systematic study exists. We developed a coding system to identify playful teasing and applied it to video of zoo-housed great apes. All four species engaged in intentionally provocative behaviour, frequently accompanied by characteristics of play. We found playful teasing to be characterized by attention-getting, one-sidedness, response looking, repetition and elaboration/escalation. It takes place mainly in relaxed contexts, has a wide variety of forms, and differs from play in several ways (e.g. asymmetry, low rates of play signals like the playface and absence of movement-final 'holds' characteristic of intentional gestures). As playful teasing is present in all extant great ape genera, it is likely that the cognitive prerequisites for joking evolved in the hominoid lineage at least 13 million years ago.

Sex differences in the structure and function of the vasopressin system in the ventral pallidum are associated with the sex-specific regulation of social play behavior in juvenile rats.

Vasopressin (AVP) regulates various social behaviors, often in sex-specific ways, including social play behavior, a rewarding behavior displayed primarily by juveniles. Here, we examined whether and how AVP acting in the brain's reward system regulates social play behavior in juvenile rats. Specifically, we focused on AVP signaling in the ventral pallidum (VP), a brain region that is a part of the reward system. First, we examined the organization of the VP-AVP system in juvenile rats and found sex differences, with higher density of both AVP-immunoreactive fibers and AVP V1a receptor (V1aR) binding in males compared to females while females show a greater number of V1aR-expressing cells compared to males. We further found that, in both sexes, V1aR-expressing cells co-express a GABA marker to a much greater extent (approx. 10 times) than a marker for glutamate. Next, we examined the functional involvement of V1aR-expressing VP cells in social play behavior. We found that exposure to social play enhanced the proportion of activated V1aR-expressing VP cells in males only. Finally, we showed that infusion of a specific V1aR antagonist into the VP increased social play behaviors in juvenile male rats while decreasing these behaviors in juvenile female rats. Overall, these findings reveal structural and functional sex differences in the AVP-V1aR system in the VP that are associated with the sex-specific regulation of social play behavior.

Prenatal allergic inflammation in rats confers sex-specific alterations to oxytocin and vasopressin innervation in social brain regions.

Prenatal exposure to inflammation via maternal infection, allergy, or autoimmunity increases one's risk for developing neurodevelopmental and psychiatric disorders. Many of these disorders are associated with altered social behavior, yet the mechanisms underlying inflammation-induced social impairment remain unknown. We previously found that a rat model of acute allergic maternal immune activation (MIA) produced deficits like those found in MIA-linked disorders, including impairments in juvenile social play behavior. The neuropeptides oxytocin (OT) and arginine vasopressin (AVP) regulate social behavior, including juvenile social play, across mammalian species. OT and AVP are also implicated in neuropsychiatric disorders characterized by social impairment, making them good candidate regulators of social deficits after MIA. We profiled how acute prenatal exposure to allergic MIA changed OT and AVP innervation in several brain regions important for social behavior in juvenile male and female rat offspring. We also assessed whether MIA altered additional behavioral phenotypes related to sociality and anxiety. We found that allergic MIA increased OT and AVP fiber immunoreactivity in the medial amygdala and had sex-specific effects in the nucleus accumbens, bed nucleus of the stria terminalis, and lateral hypothalamic area. We also found that MIA reduced ultrasonic vocalizations in neonates and increased the stereotypical nature of self-grooming behavior. Overall, these findings suggest that there may be sex-specific mechanisms underlying MIA-induced behavioral impairment and underscore OT and AVP as ideal candidates for future mechanistic studies.

Captains on call: A qualitative investigation of an intervention to support children with retinoblastoma undergoing regular eye examinations.

BACKGROUND: Retinoblastoma is a rare childhood ophthalmic cancer that requires frequent eye examinations under anaesthesia and painful or distressing procedures. This can cause significant anxiety for children and their families. OBJECTIVE: We evaluated a Starlight Children's Foundation programme, 'Captains on Call', at the Queensland Children's Hospital, which aims to provide positive distraction and reduce stress, anxiety and pain during the perioperative journey for children in the retinoblastoma treatment pathway. This study examined the impact of the programme on the perioperative experience of the children and their families, using a qualitative design. METHODS: This study was conducted in a paediatric operating suite at a tertiary-level children's hospital in Australia. We interviewed a parent from 20 families (from a cohort of 40 families, including 44 children), whose children received treatment or screening for retinoblastoma, focusing on the programme's impact on the child and family at various stages during the perioperative journey. We undertook a thematic analysis of transcribed interviews. RESULTS: We identified two themes, each with two sub-themes: (1) the programme positively contributed to the overall treatment journey, by addressing different needs at different times, and helping to reframe a traumatic medical experience, and (2), the programme supported the whole family unit by empowering children through play, and adopting a family systems approach which recognised the impact of cancer treatment on the whole family. CONCLUSION: This study highlights the value of the Captains on Call programme in supporting children with retinoblastoma and their families during perioperative visits. The Captains, particularly as non-medicalised professionals in a healthcare setting, built trust and rapport with the children through play over repeated episodes of care. The interprofessional collaborative approach with a reflective cycle of practice extended it beyond a programme providing simple distraction. Other retinoblastoma services may benefit from implementing a similar approach.

Developmental trends in young children's device-measured physical activity and sedentary behaviour.

BACKGROUND: Knowledge of developmental trends in meeting age-specific 24-hour movement behaviour guidelines is lacking. This study describes developmental trends in device-measured physical activity and sedentary time over a three-year period among Western Australian children aged two to seven years, including differences between boys and girls. The proportion of children meeting age-specific physical activity guidelines before and after they transition to full-time school was also examined. METHODS: Data from waves 1 and 2 of the Play Spaces and Environments for Children's Physical Activity (PLAYCE) cohort study were used (analysis n = 1217). Physical activity and sedentary time were measured by accelerometry at ages two to five (preschool, wave 1) and ages five to seven (commenced full-time school, wave 2). Accelerometer data were processed using a validated machine-learning physical activity classification model. Daily time spent in sedentary behaviour, energetic play (moderate-to-vigorous physical activity (MVPA)), total physical activity, and meeting physical activity guidelines were analysed using linear and generalised linear mixed-effects models with age by sex interaction terms. RESULTS: All movement behaviours changed significantly with increasing age, and trends were similar in boys and girls. Total daily physical activity increased from age two to five then declined to age seven. Mean daily total physical activity exceeded 180 min/day from ages two to five. Daily energetic play increased significantly from age two to seven, however, was below 60 min/day at all ages except for seven-year-old boys. Daily sedentary time decreased to age five then increased to age seven but remained lower than at age two. All two-year-olds met their age-specific physical activity guideline, decreasing to 5% of girls and 6% of boys at age four. At age seven, 46% of boys and 35% of girls met their age-specific physical activity guideline. CONCLUSIONS: Young children's energetic play and total physical activity increased with age, but few children aged three to seven met the energetic play (MVPA) guideline. Interventions should focus on increasing children's energetic play in early childhood. Clearer guidance and strategies are needed to support young children as they change developmentally and as they transition from one age-specific movement guideline to the next.

Reliability and validity of rapid assessment tools for measuring 24-hour movement behaviours in children aged 0-5 years: the Movement Behaviour Questionnaire Baby (MBQ-B) and child (MBQ-C).

BACKGROUND: The development of validated "fit-for-purpose" rapid assessment tools to measure 24-hour movement behaviours in children aged 0-5 years is a research priority. This study evaluated the test-retest reliability and concurrent validity of the open-ended and closed-ended versions of the Movement Behaviour Questionnaire for baby (MBQ-B) and child (MBQ-C). METHODS: 300 parent-child dyads completed the 10-day study protocol (MBQ-B: N = 85; MBQ-C: N = 215). To assess validity, children wore an accelerometer on the non-dominant wrist (ActiGraph GT3X+) for 7 days and parents completed 2 × 24-hour time use diaries (TUDs) recording screen time and sleep on two separate days. For babies (i.e., not yet walking), parents completed 2 × 24-hour TUDs recording tummy time, active play, restrained time, screen time, and sleep on days 2 and 5 of the 7-day monitoring period. To assess test-retest reliability, parents were randomised to complete either the open- or closed-ended versions of the MBQ on day 7 and on day 10. Test-retest intraclass correlation coefficients (ICC's) were calculated using generalized linear mixed models and validity was assessed via Spearman correlations. RESULTS: Test-retest reliability for the MBQ-B was good to excellent with ICC's ranging from 0.80 to 0.94 and 0.71-0.93 for the open- and closed-ended versions, respectively. For both versions, significant positive correlations were observed between 24-hour diary and MBQ-B reported tummy time, active play, restrained time, screen time, and sleep (rho = 0.39-0.87). Test-retest reliability for the MBQ-C was moderate to excellent with ICC's ranging from 0.68 to 0.98 and 0.44-0.97 for the open- and closed-ended versions, respectively. For both the open- and closed-ended versions, significant positive correlations were observed between 24-hour diary and MBQ-C reported screen time and sleep (rho = 0.44-0.86); and between MBQ-C reported and device-measured time in total activity and energetic play (rho = 0.27-0.42). CONCLUSIONS: The MBQ-B and MBQ-C are valid and reliable rapid assessment tools for assessing 24-hour movement behaviours in infants, toddlers, and pre-schoolers. Both the open- and closed-ended versions of the MBQ are suitable for research conducted for policy and practice purposes, including the evaluation of scaled-up early obesity prevention programs.

Disentangling developmental effects of play aspects in rat rough-and-tumble play.

Animal play encompasses a variety of aspects, with kinematic and social aspects being particularly prevalent in mammalian play behaviour. While the developmental effects of play have been increasingly documented in recent decades, understanding the specific contributions of different play aspects remains crucial to understand the function and evolutionary benefit of animal play. In our study, developing male rats were exposed to rough-and-tumble play selectively reduced in either the kinematic or the social aspect. We then assessed the developmental effects of reduced play on their appraisal of standardized human-rat play ('tickling') by examining their emission of 50 kHz ultrasonic vocalizations (USVs). Using a deep learning framework, we efficiently classified five subtypes of these USVs across six behavioural states. Our results revealed that rats lacking the kinematic aspect in play emitted fewer USVs during tactile contacts by human and generally produced fewer USVs of positive valence compared with control rats. Rats lacking the social aspect did not differ from the control and the kinematically reduced group. These results indicate aspects of play have different developmental effects, underscoring the need for researchers to further disentangle how each aspect affects animals.

Hyoid fracture: consensual sex-play or non-consensual nonfatal strangulation: a case report.

Hyoid fractures are uncommon, but when they occur they are commonly the result of strangulation or hanging. Although there is a lack of available quantitative data, there is increasing evidence to suggest that strangulation is a relatively common feature of consensual sex play. This creates difficulty in clinical forensic medicine given the "rough sex" defence has previously been used successfully in cases of fatal intimate partner strangulation. We present a case where consensual and non-consensual strangulation has occurred in a woman who presents with a hyoid fracture. While manual strangulation was thought to be a more likely mechanism than consensual wearing of a sex-collar; ultimately the similar timeframes of the collar-wearing and the non-consensual manual strangulation meant that the accused was not convicted of this particular strangulation offense. This case highlights the importance of further research into consensual strangulation and the incidence of resultant injuries. It also demonstrates the importance of collecting a detailed forensic history and adequately documenting injuries in a contemporaneous matter.

Mock court: a valuable tool to teach legal procedures to undergraduate medical students.

BACKGROUND: Teaching through role-plays is a preferred modality when certain behaviours or skills need to be taught. They provide a risk-free environment that simulates a real-life scenario. For a clinician, appearance in a Court of Law as an expert witness is a part of his/her legal obligation. OBJECTIVE: To explore the utility of Mock Court as an additional teaching tool for undergraduate medical students, in understanding and familiarizing with legal procedures, specifically the courtroom procedures. METHODOLOGY: We conducted Mock Court sessions with the students playing various roles, following which feedback was collected from the students, teachers and guest assessors. The data was statistically analysed by comparison of frequencies and paired t-test (pre- and post-session comparison). RESULTS: The study revealed a positive effect of the Mock Court sessions on the students, based on their increased confidence, motivation and a better grasp of legal procedures. There was a statistically significant (p < 0.001) improvement in the understanding of specific aspects of courtroom procedures after the session. CONCLUSION: The authors recommend the active implementation of Mock Court as a teaching aid for undergraduate medical students, and the use of PDSA (Deming) cycle as a tool for quality-checks and self-improvement in subsequent sessions.

Social play behavior shapes the development of prefrontal inhibition in a region-specific manner.

Experience-dependent organization of neuronal connectivity is critical for brain development. We recently demonstrated the importance of social play behavior for the developmental fine-tuning of inhibitory synapses in the medial prefrontal cortex in rats. When these effects of play experience occur and if this happens uniformly throughout the prefrontal cortex is currently unclear. Here we report important temporal and regional heterogeneity in the impact of social play on the development of excitatory and inhibitory neurotransmission in the medial prefrontal cortex and the orbitofrontal cortex. We recorded in layer 5 pyramidal neurons from juvenile (postnatal day (P)21), adolescent (P42), and adult (P85) rats after social play deprivation (between P21 and P42). The development of these prefrontal cortex subregions followed different trajectories. On P21, inhibitory and excitatory synaptic input was higher in the orbitofrontal cortex than in the medial prefrontal cortex. Social play deprivation did not affect excitatory currents, but reduced inhibitory transmission in both medial prefrontal cortex and orbitofrontal cortex. Intriguingly, the reduction occurred in the medial prefrontal cortex during social play deprivation, whereas the reduction in the orbitofrontal cortex only became manifested after social play deprivation. These data reveal a complex interaction between social play experience and the specific developmental trajectories of prefrontal subregions.

Monitoring the acute and subacute recovery of cognitive ocular motor changes after a sports-related concussion.

Identifying when recovery from a sports-related concussion (SRC) has occurred remains a challenge in clinical practice. This study investigated the utility of ocular motor (OM) assessment to monitor recovery post-SRC between sexes and compared to common clinical measures. From 139 preseason baseline assessments (i.e. before they sustained an SRC), 18 (12 males, 6 females) consequent SRCs were sustained and the longitudinal follow-ups were collected at 2, 6, and 13 days post-SRC. Participants completed visually guided, antisaccade (AS), and memory-guided saccade tasks requiring a saccade toward, away from, and to a remembered target, respectively. Changes in latency (processing speed), visual-spatial accuracy, and errors were measured. Clinical measures included The Sports Concussion Assessment Tool, King-Devick test, Stroop task, and Digit span. AS latency was significantly longer at 2 days and returned to baseline by 13-days post-SRC in females only (P < 0.001). Symptom numbers recovered from 2 to 6 days and 13 days (P < 0.05). Persistently poorer AS visual-spatial accuracy was identified at 2, 6 and 13 days post-SRC (P < 0.05) in both males and females but with differing trajectories. Clinical measures demonstrated consistent improvement reminiscent of practice effects. OM saccade assessment may have improved utility in tracking recovery compared to conventional measures and between sexes.

Superhero Pretense, Superhero Identification, and Risk-Taking in Preschool-Aged Children.

OBJECTIVE: The preschool years represent a stage of rapid human development, hallmarked by exploring the environment through gross and fine motor movement and imaginative pretend play. This exploration is developmentally appropriate but also presents risks for injury, the leading cause of death for preschool-aged children. Common injuries reflect exploration and risk-taking exhibited during play, and play may be particularly risky when children imitate risky models like superheroes. Frequent exposure and subsequent identification with superheroes are concerning because the media glorifies superheroes, creating social learning effects on children and promoting play situations where children may attempt superhuman abilities and hurt themselves. This study examined the relations between pretend play, superhero identification, and children's risk-taking. METHODS: One hundred five children aged 4-5 years old were randomly assigned to either a superhero- or school-themed, story-based protocol. In both conditions, children engaged in three identical behavioral tasks to assess risk-taking. Identification with superheroes was measured using parent-report questionnaires and child interviews. RESULTS: Pretending to be a superhero was not associated with increased risk-taking behavior acutely, but identification with superheroes was associated in some analyses with preschool children's broader risk-taking behavior. Across risk-taking behavior tasks, children with high superhero identification pretending to be superheroes tended to take the most risks. CONCLUSIONS: Given the popularity of superhero media and the present results suggesting superhero identification may relate to injury-risk situations during play, prevention efforts should consider ways to reduce young children's exposure to superheroes and/or mitigate injury risk during active pretend play.

Prevalence of Sexual Strangulation/Choking Among Australian 18-35 Year-Olds.

In Australia, strangulation has been explicitly criminalized in all states and territories. However, it continues to be a "normalized" sexual practice despite its potentially fatal consequences and associated short and long-term sequelae. This research aimed to establish the prevalence of strangulation during sex and examine predictors of positive perceptions toward sexual strangulation in Australia. Confidential, cross-sectional online surveys were conducted with 4702 Australians aged 18-35 years. Participants were 47% cis-men, 48% cis-women, and 4% trans or gender diverse. A total of 57% reported ever being sexually strangled (61% women, 43% men, 79% trans or gender diverse) and 51% reported ever strangling a partner (40% women, 59% men, 74% trans or gender diverse). Differences were found across genders on all variables of sexual strangulation, including frequency of engagement, level of pressure on the neck, consequences, wanting and enjoyment, and how consent was given/received. However, when split by gender, sexual orientation of men and women revealed further differences in behaviors, consequences, and wanting, particularly among straight and bisexual women. After accounting for exposure to strangulation in pornography and previous experience of sexual strangulation, positive perceptions of being strangled (R2 = .51) and strangling a partner (R2 = .53) were predicted by ratings that it could be done safely and social normative factors. These findings suggest strangulation is common during sex among young Australians. Non-stigmatizing education strategies are needed to engage with young people so they have a better understanding of the risks involved and how to negotiate consent and safety regarding sexual strangulation.

Observations on Gender Variance in Chinese Community Children Measured by the Gender Identity Questionnaire for Children.

Few studies have examined how gender variance (GV), broadly defined as gender identity and behaviors (e.g., activities and preferences) that do not correspond with culturally defined gender norms, manifests in community samples, particularly in children and outside Western contexts. We present data based on the Gender Identity Questionnaire for Children (GIQC; Johnson et al., 2004) among 461 Chinese community children (4-12 years old) to gauge how well the GIQC serves as a measure of GV and the prevalence of GV. We examined the descriptive scores of GV, its relationship to a gender-typing measure that has been validated in Chinese children (the Child Play Behavior and Activity Questionnaire, CPBAQ), the scores on the GIQC of children whose gender is incongruent with birth-assigned sex, and the binned category distributions (from gender-variant to gender-conforming) in comparison to a Canadian community sample (van der Miesen et al., 2018). The Chinese children on average scored toward the gender-conforming end and children assigned female at birth showed more GV than children assigned male at birth. More importantly, the GIQC appears to be a reliable and sensitive measure of GV in the Chinese sample. GIQC scores correlated significantly with CPBAQ scores and showed a very similar reliability coefficient, gender difference effect size, and bin distribution pattern as the Canadian reference sample. Also, children reported as gender/sex incongruent had the most gender-variant GIQC scores. Although clinically gender-referred Chinese children are required to establish culturally specific cutoff points, these findings provide initial evidence for the characteristics of GV, the applicability of the GIQC as a measure of GV in Chinese community children, and the comparisons of GIQC categories between Chinese and Canadian community samples.

Establishing consensus on principles and competencies for the use of play in clinical practice in hospitals: An international Delphi study.

Although play has existed in paediatric hospitals for decades, a shared understanding of why and how healthcare professionals use play in clinical practice is lacking. This study aims to reach consensus on a common set of principles and competencies for play interventions and practices in hospitals. We conducted a three-round Delphi study that included healthcare professionals selected by hospital management. The first round comprised open-ended questions on the use of play in clinical practice. Principles and competencies, including learning objectives, were established using content analysis through an iterative process. Participants rated the importance of each principle and learning objective in the second and third rounds. Among the 66 participants, 45 (68%) responded in round 1 and 41 (62%) in rounds 2 and 3. The participants represented ten countries and nine different health professions. After the three rounds, we identified 33 principles and six overall competencies: building trusting relationships; delivering information and increasing understanding; promoting cooperation and participation; reducing procedure-related anxiety and pain; supporting coping and development; and ensuring a professional approach to play, which comprised 20 learning objectives.  Conclusion: According to healthcare professionals, play in clinical practice can be used to communicate and build relationships with paediatric patients and thus potentially help provide patient-centred care. Our findings may help guide and prioritize future research initiatives and operationalize play interventions and practices in hospitals. What is Known: • Evidence suggests that using play in clinical practice can help paediatric patients during hospitals stays. • Despite the evidence supporting the use of play, a shared understanding of why and how paediatric healthcare professionals use play is needed. What is New: • This international Delphi study contributes to a shared interprofessional understanding of the principles, competencies and learning objectives for the use of play in clinical practice. • The findings have the potential to aid initiatives in developing training programmes for healthcare professionals in using play to provide care with a patient-centred approach.

Preschoolers negatively evaluate conventional norm violations in pretend play.

A growing body of research demonstrates that children's pretend play is largely influenced by their understanding of reality. The current work took a novel approach to testing children's understanding of pretense by investigating whether children apply and uphold their knowledge of conventional norms in pretend play. In this study, 3- to 5-year-old children (N = 200) were introduced to a series of pretend play scenarios (e.g., pretending to eat breakfast) in which a puppet pretended to follow a norm (e.g., pretended to eat cereal for breakfast) or violate a norm (e.g., pretended to eat a hamburger for breakfast). These pretend play scenarios were presented as either fantastical or realistic in nature. Consistent with our hypotheses, children evaluated pretend norm violation more negatively than pretend norm adherence and reported liking norm violators less than norm followers. Contrary to our hypothesis, the manipulation of play context (fantastical vs. realistic) did not affect children's evaluations. That is, children were just as negative about pretend norm violations (relative to pretend norm adherence) in fantastical pretend play scenarios as they were in realistic pretend play scenarios. Furthermore, individual differences in children's fantasy orientation did not predict their evaluations. This study is the first to establish that children maintain their real-world understanding of conventional norms in pretend play, providing further evidence that children's pretense is largely realistic in nature.