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.

Integrating Post-Ionization Separation via Differential Mobility Spectrometry into Direct Analysis in Real Time Mass Spectrometry for Toy Safety Screening.

Direct analysis in real time (DART) enables direct desorption and ionization of analytes, bypassing the time-consuming chromatographic separation traditionally required for mass spectrometry (MS) analysis. However, DART-MS suffers from matrix interference of complex samples, resulting in compromised detection sensitivity and quantitation accuracy. In this study, DART-MS was combined with differential mobility spectrometry (DMS) to provide an additional dimension of post-ionization ion mobility separation within a millisecond time scale, compensating for the lack of separation in DART-MS analysis. As proof-of-concept, primary aromatic amines (PAAs), a class of potentially hazardous chemicals, were analyzed in various toy products, including bubble solutions, finger paints, and plush toys. In addition to commercial Dip-it glass rod and metal mesh sampling tools, a customized rapid extractive evaporation device was designed for the accelerated extraction and sensitive analysis of solid toy samples. The incorporation of DMS in DART-MS analysis enabled the rapid separation and differentiation of isomeric analytes, leading to improved accuracy and reliability. The developed protocols were optimized and validated, achieving good linearity with correlation coefficients greater than 0.99 and acceptable repeatability with relative standard deviations less than 10%. Moreover, satisfactory sensitivity was realized with limits of detection and quantitation ranges of 0.2-5 and 1-20 µg/kg (µg/L) for the 11 PAA analytes. The established methodology was applied for the analysis of real toy samples (n = 18), which confirmed its appealing potential for toy safety screening and consumer health protection.

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.

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.

The role of playgrounds in promoting children's health - a scoping review.

BACKGROUND: Active outdoor play is important for children's health and development, and playgrounds provide good places for play. However, the importance of playground use for health and well-being is unclear. Our scoping review aims to create an overview of all research on playground use and health benefits for children. METHODS: Scopus, Web of Science, SportDiscus, and PsycInfo were searched using two search blocks, focusing on 'playground' and 'children' respectively, for publications from 2000 to November 2023. The primary inclusion criterion was examining the relationship between playground use and positive physical, mental, or social health outcomes. Only papers published in English were reviewed. For each publication, we synthesized and condensed the results, categorizing them by playground setting, reported health outcome, participant age group, study design, methodologies, publication's country, year, and 'stage of evidence'. RESULTS: Data from 247 studies were extracted and nearly 80% of these publications were descriptive or exploratory studies. Fifty-two were intervention studies. Adding playground markings to schoolyards led to increased physical activity. Greening schoolyards had mainly positive effects on social and mental health. In Early Childhood Education and Care, renewing play structures had a positive effect on physical activity in three publications. All Public Open Space interventions we found were different, with mixed effects on health outcomes. CONCLUSIONS: The existing evidence provides good arguments for policy makers, city planners and school-leaders to invest in adding playground markings in schoolyards as this will likely result in more physical activity. The evidence for the health benefits of investing in new play structures indicated that tailoring the playground to local needs is important as 'one size does not fit all' and playgrounds need to be designed as engaging and interesting places for children's play if they are to generate health benefits. Investing in 'greening' playgrounds is likely to result in social and mental health benefits for children, but does not always result in more physical activity. The research field needs more efficacy and effectiveness studies, and in particular replication and scale-up studies to demonstrate which type of playground interventions are successful. PROTOCOL: The review protocol was registered at Open Science Framework ( https://doi.org/10.17605/OSF.IO/UYN2V ).

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.

Fatal bowel perforation caused by ingestion of high-powered magnets in a 6-year-old boy.

Foreign body ingestion in children is a frequent cause for medical consultation. Although most foreign bodies are spontaneously eliminated from the gastrointestinal tract, life-threatening complications such as gastrointestinal obstruction or perforation can occur. We report the case of a 6-year-old boy who died 2 days after the onset of nausea and abdominal pain, with no foreign body ingestion witnessed or reported in the previous days. Autopsy showed a diffuse peritonitis and a perforation of the transverse colon caused by three high-powered magnets stacked together, and attached to the outer stomach wall via a fourth magnet located in the stomach. The cause of death was peritonitis due to bowel perforation by ingested magnets, which were shown to have come from a toy belonging to the child. Ingestion of multiple high-powered magnets carries a high risk of gastrointestinal complications and can exceptionally have a fatal outcome, especially as it often goes unreported and causes non-specific gastrointestinal symptoms that can delay diagnosis and management. This case highlights the need to raise public awareness of the potential risks of ingesting such magnets and to strengthen safety standards to protect children from this serious health hazard.

Controlling the input: How one-year-old infants sustain visual attention.

Traditionally, the exogenous control of gaze by external saliencies and the endogenous control of gaze by knowledge and context have been viewed as competing systems, with late infancy seen as a period of strengthening top-down control over the vagaries of the input. Here we found that one-year-old infants control sustained attention through head movements that increase the visibility of the attended object. Freely moving one-year-old infants (n = 45) wore head-mounted eye trackers and head motion sensors while exploring sets of toys of the same physical size. The visual size of the objects, a well-documented salience, varied naturally with the infant's moment-to-moment posture and head movements. Sustained attention to an object was characterized by the tight control of head movements that created and then stabilized a visual size advantage for the attended object for sustained attention. The findings show collaboration between exogenous and endogenous attentional systems and suggest new hypotheses about the development of sustained visual attention.

Direct and indirect effects of mother's spatial ability on child's spatial ability: What role does the home environment play?

Individual differences in spatial thinking are predictive of children's math and science achievement and later entry into Science, Technology, Engineering, and Mathematics (STEM) disciplines. Little is known about whether parent characteristics predict individual differences in children's spatial thinking. This study aims to understand whether, and to what extent, mother's intrinsic (i.e., mental rotation) and extrinsic (i.e., spatial scaling) spatial ability directly and indirectly, via the variation in home spatial environment, predicts children's intrinsic and extrinsic spatial ability. A total of 165 mothers and their 4-6-year-old children were recruited to participate in a remote video session with an experimenter. Mothers were administered a forced-choice Intrinsic Spatial Toy Preference Task gauging their preference for highly spatial versus less spatial toys and asked questions with the Home Intrinsic Spatial Environmental Questionnaire about the frequency with which they engage their child in spatial activities at home. Mothers completed a Mental Rotations Test and a Spatial Scaling Task adapted for adults. Children were administered the Picture Rotation Task, the Spatial Scaling Task, and the Peabody Picture Vocabulary Test. Structural equation modeling was used to examine direct and indirect, via home spatial environment and toy choices, influences of mother spatial ability on child spatial ability. Contrary to our predictions, we did not find direct, nor indirect, relations between mother and child spatial ability. These findings suggest that researchers should consider alternative conceptualizations of the early home spatial environment beyond the frequency of spatial play in the home. RESEARCH HIGHLIGHTS: The identification of factors that predict individual differences in children's spatial ability is important in order to maximize STEM learning outcomes. Data collection was conducted remotely rather than in traditional preschool or laboratory settings. Contrary to our pre-registered hypotheses, no significant relations between mother spatial ability, the early home spatial environment, and children's development of spatial skills were found. Future research should consider examining the amount of spatial language used in the home or the quality of parent-child interactions during spatial play as potential explanations for individual differences in children's spatial ability.

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.

A Pilot Randomized Trial Evaluating the Cool 2 Be Safe Junior Playground Safety Program for Preschool Children.

OBJECTIVE: Unintentional injury is the leading cause of death to children worldwide, and playgrounds pose a significant risk of injury. Those aged 5 and 6 years are particularly vulnerable to playground injuries. Previous interventions have typically targeted environmental modifications or increased supervision to reduce playground injuries; however, minimal research has focused on implementing behavioral interventions that seek to change children's safety knowledge and risk-taking behaviors on the playground. The current randomized trial addressed these gaps in the literature and sought to increase preschool children's hazard awareness skills and knowledge of unsafe playground behaviors and decrease their intentions to engage in risk-taking behaviors on the playground. METHOD: A total of 77 children aged 5 and 6 years were tested at a laboratory on a university campus, using a parallel group design, with 38 randomized to the playground intervention group and 39 randomly assigned to a control group. The intervention was manualized and delivered to small groups of children (3-5) over several sessions. RESULTS: Statistical analyses revealed significant group differences. Intervention experience led to significant increases in hazard awareness skills and knowledge of unsafe playground behaviors, and significant decreases in children's risk-taking behavioral intentions, whereas those in the control group showed no significant changes in these scores. Attention scores for those in the intervention group highlighted that the program content was successful in maintaining children's attention and engagement, and memory scores indicated excellent retention of lesson content. CONCLUSION: The program shows promise in addressing the issue of unintentional playground injuries in young children.

Sexual Behaviors as a Mediator Between Pornography Use and Heterosexual Relationship Outcomes.

This study seeks to build on previous research about how pornography use is associated with relationship outcomes. Using the 3AM model (Wright, 2011) as a theoretical guide, sexual behaviors were tested as a possible mediator of the association between pornography use and relationship well-being. Using a national data set of individuals in heterosexual relationships (n = 2519), associations between different types of pornography use (alone use vs. joint use), sexual behaviors, and relationship outcomes were analyzed. Results showed that pornography use with a partner is a distinct activity when compared to pornography use alone. Additionally, significant indirect relationships between pornography use and relationship outcomes were found through sexual behaviors. Both vaginal sex and oral sex had positive effects, while anal sex had a unique, negative effect (use of sex toys was not significantly related). Future research should continue to examine the context of pornography use and how it is related to behaviors and outcomes in relationships.

Are Gender Identities and Gender Ideologies Associated with the Variety and Type of Owned Sex Toys? Evidence from a Large Italian Sample of Cisgender Individuals.

Research on the use of sex toys has been primarily performed from a medical perspective, while there is still limited research from a psychosocial perspective. To bridge this gap, in this study we examined whether some psychosocial variables might be linked to sex toy ownership in a sample of 3960 Italian (cisgender men and women) sex toy buyers. More specifically, we investigated the association between gender identities and ideologies and the variety and types of sex toys owned. Based on the data, we detected two dimensions underlying the ownership of sex toys: (1) orientation to owning kinky sex toys and (2) orientation to owning clit-oriented sex toys. Results showed that benevolent sexism and gender system justification were negatively correlated with owning clit-oriented toys. Moreover, strongly gender-identified participants owned a small variety of different toys and preferred toys that were designed to stimulate the vagina or clitoris over less commonly-used toys. No significant correlation between feminist identification and sex toy type owned was found when gender identification was taken into account. These results suggest that the owning of sex toys might be associated with traditional gender ideology and the strength of gender identification.

Thought and language: Effects of group-mindedness on young children's interpretation of exclusive we.

The current study investigated whether age-related changes in the conceptualization of social groups influences interpretation of the pronoun we. Sixty-four 2- and 4-year-olds (N = 29 female, 50 White-identifying) viewed scenarios in which it was ambiguous how many puppets performed an activity together. When asked who performed the activity, a speaker puppet responded, "We did!" In one condition, the speaker was near one and distant from another puppet, implying a dyadic interpretation of we. In another condition, the speaker was distant from both, thus pulling for a group interpretation. In the former condition, 2- and 4-year-olds favored the dyadic interpretation. In the latter condition, only 4-year-olds favored the group interpretation. Age-related conceptual development "expands" the set of conceivable plural person referents.

Scaling up healthy eating in early childhood education and care: evaluation of the Appetite to Play capacity-building intervention.

OBJECTIVE: The purpose of this study was to examine the dissemination of the healthy eating component of Appetite to Play at scale using the Reach, Effectiveness, Adoption, Implementation, Maintenance (RE-AIM) framework. DESIGN: The Appetite to Play capacity-building intervention is a set of evidence-informed implementation strategies aimed at enhancing the adoption of recommended practices for promoting healthy eating and active play in early years settings. The evaluation was pragmatic, employing both quantitative (surveys) and qualitative (interviews) data collection. SETTING: The Appetite to Play intervention was delivered through in-person community-based workshops, virtual workshops, asynchronous e-learning and online resources. PARTICIPANTS: We received completed surveys from 1670 in-person workshop participants (96 % female), and twenty-three (all female) survey respondents also participated in a telephone interview. Approximately two-thirds of all participant groups were certified early childhood educators. RESULTS: Results indicated that Appetite to Play had high reach (25 867 individual website visits, 195 workshops delivered), effectiveness (significant increases in care provider's knowledge, confidence (P < 0·05) and high post-intervention intention to implement), adoption (11 % of educators in BC trained) and implementation (good alignment with implementation strategies and current practices), with a significant maintenance plan to support the intervention's future success. CONCLUSIONS: An evidence-based capacity-building intervention with an emphasis on training and provision of practical online resources can improve early years providers' knowledge, confidence and intention to implement recommended practices that promote healthy eating. Further research is needed to determine the impact on child-level outcomes and how parents can be supported in contributing to positive food environments.

Object play and problem solving in infancy: Insights into tool use.

Tool use is primarily, but not exclusively, present in species with otherwise advanced cognitive traits. However, the interaction between such traits and conspecific inter-individual variation in the presence, complexity, or intensity of tool use is far from being established. We addressed this matter among human infants, seeking factors that relate to differences in tool use. We examined, both correlationally and experimentally, whether the propensity to engage in object combinations predicts performance in means-end problem-solving tasks involving or not involving the use of a tool. We tested 71 infants aged 15, 18, 21, and 24 months, dividing them into two subgroups: one exposed to an adult demonstrating object-object combinations (i.e., "prompting" infants to combine objects together) and another with comparable social exposure but where the adult demonstrated single-object manipulations. We found a correlation between the combined level of spontaneous and prompted object combinations and problem-solving performance regardless of the involvement of tools in the problem. However, we did not find differences in tool-use performance between the two demonstration subgroups. The correlational analysis suggests that complexity of play, as measured by the frequency of combining objects, is linked to infants' problem-solving skills rather than being specifically associated with tool use, as previously suggested in the literature.

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.

Math talk by mothers, fathers, and toddlers: Differences across materials and associations with children's math understanding.

Learning words for numbers, shapes, spatial relations, and magnitudes-"math talk"-relies on input from caregivers. Language interactions between caregivers and children are situated in activity contexts and likely affected by available materials. Here, we examined how play materials influence the math talk directed to and produced by young children. We video-recorded parents (mothers and fathers; English- and/or Spanish-speaking) and their 24- to 36-month-olds during play with four sets of materials, transcribed and coded types of parent and toddler math words/phrases, and assessed toddlers' understanding of number, shape, and spatial relations terms. Categories of math words varied by materials. Numeracy talk (e.g., "one," "two," "first," "second") was more frequent during interactions with a picture book and toy grocery shopping set than with a shape sorter or magnet board; the reverse held for spatial talk (e.g., "out," "bottom," "up," "circle"). Parent math talk predicted toddler math talk, and both parent and toddler math talk predicted toddlers' understanding of spatial and number words. Different materials provide unique opportunities for toddlers to learn abstract math words during interactions with caregivers, and such interactions support early math cognition.