Spontaneous behavior during recess and social-emotional adjustment in first-grade children: a multifactorial longitudinal study

1 Introduction

Childhood represents a critical window for acquiring the self-regulation and interpersonal skills that underpin academic success and lifelong wellbeing (Raver et al., 2012; OECD, 2015; Whitebread, 2017). During their early school years, children must learn to navigate increasingly complex social environments, manage emotions, form and maintain friendships, and respond to normative social pressures (Gazelle and Ladd, 2003; Son'kin et al., 2024). These developmental demands are foundational to social-emotional learning, which encompasses self-awareness, self-management, social awareness, and responsible decision-making [Collaborative for Academic, Social, and Emotional Learning (CASEL), 2020; Greenberg, 2023].

Adequate social-emotional adjustment (SEA) is reflected not only in the absence of internalizing or externalizing problems, but also in the presence of positive peer relationships, effective inhibitory control, and adaptive self-management (Madariaga et al., 2014; Domitrovich et al., 2017). Although inhibitory control is traditionally considered an executive function, it plays a fundamental role in children's emotional regulation and socially appropriate behavior (Blair and Raver, 2015; Dumont et al., 2024). For simplicity and consistency, we refer to this integrated construct as social-emotional adjustment (SEA) throughout the manuscript. In short, SEA reflects the constellation of emotional, behavioral, and interpersonal competencies that support children's successful participation in school life.

School recess has been identified as an exceptionally rich context for social-emotional development. Unstructured play offers opportunities for exploration of physical space, initiation and negotiation of social interactions, and practice of emotional and behavioral self-regulation outside teacher-directed settings (Poulos and Kulinna, 2022; Veiga et al., 2017a). Activities that children engage at recess, such as cooperative games, social play, and conversations, have been described as “the primary source of development in the early years,” promoting adaptability, resilience, and social-emotional health (Ginsburg et al., 2007; Hewes, 2006). Peer group processes during recess are therefore highly relevant to children's SEA (Ladd, 2006).

However, not all children can benefit equally from these opportunities. Children with lower self-regulation (Backer-Grøndahl et al., 2019; Spinrad et al., 2004), elevated internalizing symptoms (shyness, anxiety, depression) (Gazelle and Ladd, 2003; Grose and Coplan, 2015; Karevold et al., 2011), or externalizing behavior problems (impulsivity, aggression) (Eisenberg et al., 2005; White et al., 2013) are more likely to experience peer exclusion or social isolation during play (Kopala-Sibley and Klein, 2017; Veiga et al., 2017b). Such patterns, characterized by reduced closeness to peers and weakened group cohesion, are associated with less favorable SEA trajectories.

Historically, research on spontaneous behavior during recess has relied on time-consuming observational coding tools (FitzGibbon et al., 2024), such as the Tool for Observing Play in the Outdoors (Loebach and Cox, 2020), the Grand Recess Observational Tool (GRF-OT) (Massey et al., 2020), the System for Observing Children's Activities and Relationships during Play (SOCARP) (Ridgers et al., 2010), or the Play Observation Scale (POS) (Rubin, 2001). Although these instruments are valid, they are limited in their ability to track large groups continuously or longitudinally. Technological innovations, including Radio Frequency Identification Devices (Veiga and Rieffe, 2018; Eichengreen et al., 2024) and Global Navigation Satellite System (GNSS) devices (Rico-González et al., 2020; Katapally et al., 2020) now allow for continuous, objective measurement of children's location, movement trajectories, peer proximity, and group coordination during recess (Andersen et al., 2015; Moreira et al., 2019; Rocha et al., 2020), reducing observer bias. When paired with standardized questionnaires and behavioral tasks, sensor-based devices provide an ecologically valid means of examining how spontaneous behavior aligns with SEA.

Importantly, cross-sectional evidence derived from sensor-based methods suggests several behavioral markers related to SEA. For example, children with greater self-control tend to remain closer to their peers during recess (Veiga et al., 2017a), indicating tighter social integration. Similarly, Nasri et al. (2022) developed a spatial mapping system to quantify exploration and social grouping; however their work was limited to a single time point. A more recent study using this GNSS-based system documented subtle patterns of peer inclusion and exclusion (Eichengreen et al., 2024), but, like previous research, it remained cross-sectional. Critically, no prior study has examined whether improvements in social-emotional functioning across the school year, correspond to changes in objective indicators such as peer proximity, group coordination, spatial exploration, or time spent alone. Building on these promising yet limited findings, the present study investigates whether changes in children's SEA unfold in parallel with changes in spontaneous behavior across the school year.

Despite the increasing use of GNSS technologies to study naturalistic peer interactions, there is currently limited longitudinal evidence examining whether changes in children's SEA and their spontaneous behavior during recess are related over time. Existing studies are predominantly cross-sectional, limiting insight into whether patterns of social behavior observed in everyday peer contexts evolves in parallel with children's social-emotional functioning across the school year. Clarifying this co-occurrence is particularly important as recess provides a highly ecologically valid context in which children express regulatory, emotional, and interpersonal capacities. The present study addresses this gap by combining multi-informant assessments of SEA with GNSS-derived behavioral indicators collected longitudinally, enabling the systematic examination of how changes in children's spontaneous social behavior unfold in relation to their evolving social-emotional functioning.

Taken together, prior research shows that children's SEA develops substantially across the early school years and is closely tied to children's engagement with peers in unstructured contexts such as recess (Domitrovich et al., 2017; Raver et al., 2012). Children with stronger regulatory and interpersonal competencies typically remain closer to peers and participate more actively in social groups (Ladd, 2006; Veiga et al., 2017a), whereas those experiencing internalizing, externalizing, or self-regulatory difficulties are more likely to experience social disengagement or exclusion (Gazelle and Ladd, 2003; Grose and Coplan, 2015; Veiga et al., 2017b). However, because past evidence is cross-sectional, it remains unknown whether changes in SEA correspond to measurable shifts in spontaneous social behavior. GNSS technologies make such examination feasible, offering a unique opportunity to map co-change in real-world peer interactions and SEA across the school year (Katapally et al., 2020; Rico-González et al., 2020).

1.1 The present study

The present study aims to examine the co-development of spontaneous behaviors and social-emotional functioning across the first year of elementary school. To capture SEA we assessed children's social-emotional functioning at the beginning (T1: November) and end (T2: June) of the school year using a multi-informant battery that included teacher reports, parent reports, and a task-based measure. From these assessments, we computed individual change scores (ΔSEA) and classified children into two adjustment profiles reflecting lower and higher gains in SEA across the school year.

To characterize children's spontaneous behavior during recess, we used GNSS devices to collect continuous and objective data on multiple behavioral indicators at both time points. These indicators included proximity to peers, mean distance to the nearest peer, mean distance to the group centroid, a spatial exploration index, a group coordination index, time spent in proximity to peers, and time spent alone. These measures allowed us to examine not only overall social engagement but also fine-grained spatial and coordination patterns that may align with children's evolving social-emotional functioning.

Finally, we compared GNSS-derived behavioral patterns between SEA profiles. This analytic strategy allowed us to examine how SEA corresponds to variations in their spontaneous behavioral engagement during recess.

Based on these objectives and previous research, we expected that (H1) SEA would improve, consistent with longitudinal evidence showing gains in regulatory, emotional, and interpersonal competencies during early schooling (Domitrovich et al., 2017; Raver et al., 2012); (H2) improvements in SEA would correspond to increases in social engagement during recess, as cross-sectional studies show that children with stronger regulatory and interpersonal abilities tend to remain closer to peers and engage more actively in group interactions (Ladd, 2006; Veiga et al., 2017a); and (H3) children with higher SEA gains would display more pronounced positive changes in spontaneous recess behavior, reflecting well-established individual differences whereby children with regulatory or emotional difficulties show greater social withdrawal or isolation (Gazelle and Ladd, 2003; Veiga et al., 2017b).

2 Methods and materials

2.1 Participants

The sample was drawn using a convenience sampling procedure based on an established partnership with a school cluster in the Alentejo region (Portugal). All first-grade children enrolled in the three participating classrooms were invited to participate. Inclusion criteria were: (a) enrollment in a first-grade class; (b) age between 5 and 8 years; (c) absence of diagnosed disability or developmental disorder, as reported by parents and teachers. No additional exclusion criteria were applied. Of the eligible students, all children whose parents provided written informed consent were included in the study, resulting in a total of 52 students (6.25 ± 0.44 years old; 23 girls). Although based on school availability and voluntary participation, the sample is reasonably representative of first-grade children in the region in terms of age, sex distribution and typical developmental status (see Table 1).

Table 1. Characteristics of age and gender of participants.

M, Mean; SD, Standard Deviation.

2.2 Procedure

This study followed a longitudinal naturalistic observational design with two waves of data collection (T1 and T2) spanning approximately six months. Both SEA assessments and GNSS-based behavioral recordings were collected at each time point to examine within-child changes over time.

Questionnaires were administered to caregivers (Strengths and Difficulties Questionnaire-SDQ and Home Community Social Behavior Scale-HCSBS) and teachers (School Social Behavior Scale, Second Edition-SSBS-2). In addition, children completed a set of assessment tasks (Head-Toes-Knees-Shoulders Task-HTKS, Happy and Sad Task-HST, and Generalized Anxiety Disorder-GAD7) at both time points. In addition, GNSS devices were used to collect positional data during recess over 7 consecutive days for each class. Data collection procedures were repeated at the end of the school year, with a minimum interval of 6 months between waves. All assessments were carried out individually at school, in a familiar for the children. The total time for the assessments was 50 minutes, divided into two 25-minute sessions to avoid fatigue. GNSS data collection took place by class level, and prior to the first day, the device and vest were presented to the children, explaining their use and the impossibility of remaining inside the building or under awnings during use. Some collection days had to be repeated due to rain.

2.3 Outcome measures

2.3.1 Self-management

Two self-management subscales were used: one from the Portuguese version of the School Social Behavior Scale (Merrell, 2002; Raimundo et al., 2012), completed by teachers (10 items), and one from the Home Community Social Behavior Scale (Merrell and Caldarella, 2002; Raimundo et al., 2009), completed by parents (15 items). Responses were provided on a 5-point Likert scale (1 = never to 5 = often), for items such as “Remains calm when problems arise” or “Adapts to different rules about their behavior in various contexts.” Scores were calculated as mean scores, with higher values indicating better self-management skills.

2.3.2 Peer relationships

Peer relationships were assessed using two subscales: one from the Portuguese version of the School Social Behavior Scale (Merrell, 2002; Raimundo et al., 2012), completed by teachers (14 items), and one from the Home Community Social Behavior Scale (Merrell and Caldarella, 2002; Raimundo et al., 2009), completed by parents (17 items). Responses were provided on a 5-point Likert scale (1 = never to 5 = often), for items such as “Offers help to other students when they need it” or “Is invited by peers to participate in activities.” Scores were calculated as mean scores with higher values indicating more positive peer relationships.

2.3.3 Externalizing problems

The Externalizing Problems index was obtained using the Portuguese version of the Strengths and Difficulties Questionnaire (SDQ) (Fleitlich et al., 2005), by combining the conduct problems subscale (5 items) and the hyperactivity subscale (5 items) (Veiga et al., 2017b). Parents rated their children's behaviors (e.g., “Often hits or bullies other children” or “Gets easily annoyed and has frequent temper tantrums”) on a 3-point Likert scale (0 = not true, 1 = somewhat true, and 2 = very true). Scores were averaged to reflect a total score ranging from 0 to 2, with higher scores indicating a higher prevalence of externalizing problems.

2.3.4 Internalizing problems

The internalizing problems index was assessed using the Portuguese version (Gonçalves, 2019) of the Generalized Anxiety Disorder Questionnaire (GAD-7) (Spitzer et al., 2006). This self-report questionnaire consists of seven items assessing the frequency of generalized anxiety symptoms (e.g., “I couldn't stop worrying or control my worries”; “I was easily annoyed or irritable”), rated on a 4-point Likert scale (0 = never, 1 = on several days, 2 = on more than half the days, 3 = almost every day). Scores were averaged to reflect a total score ranging from 0 to 3, with higher scores indicating a greater prevalence of anxiety symptoms.

2.3.5 Inhibitory control

For the analysis of inhibitory control, two tasks were selected, involving the ability to inhibit the natural tendency to give a motor response according to a verbal command or after a visual stimulus and to perform a motor response opposite to the verbal command.

The first inhibitory control task was the Head-Toes-Knees-Shoulders task (HTKS) (inhibitory control I; McClelland and Cameron, 2011; McClelland et al., 2014). In this task, each child was instructed to respond to verbal cues by performing the opposite gesture (e.g., touching their foot when told “head”; touching their head when told “foot”). The task consists of three parts that increase in difficulty. Each part includes 10 trials with scores ranging from 0 to 2 points per attempt (0 = incorrect response; 1 = self-correction during execution; 2 = correct response without hesitation). Children only advanced to the next part if they achieved a minimum score of 4 points in the previous part. The maximum total score is 60 points, with higher scores indicating better inhibitory control skills.

The second inhibitory control task was the Happy-Sad Task (HST) (inhibitory control II; Lagattuta et al., 2011). In this task, each child was instructed to say the emotional word opposite to that represented on a card (e.g., say “sad” when shown a “happy face”; “happy” when shown a “sad face”). After presenting 20 cards, the number of correct responses were registered, with higher scores indicating better inhibitory control skills. After all children had completed the tasks, the scores were standardized.

2.3.6 Global Navigation Satellite System (GNSS)

Children were monitored during recess using a GNSS geolocation and movement device for 14 days during the 2021/2022 school year, covering the beginning and end of the year. Each student wore an individual GNSS device (FieldWiz) attached to a vest. Following data collection, GNSS data were processed, and for each wave (beginning and end), the 3 days with the best data quality and highest student attendance were selected to ensure reliable averages. Based on these selected days, the following individual variables were calculated: average distance to the nearest peer; average spatial exploration index [i.e., the average distance of each student to their own average location, see Gonçalves et al. (2017)]; average distance to the center of the group; group coordination index [calculated as the percentage of time spent in a quasi-phase synchronization mode reflecting stable proximity and temporal coordination; see Folgado et al. (2014)]; time spent in proximity to peers; and time spent alone during recess (both expressed as a percentage of relative time, considering the recess period).

2.3.7 Reliability and validity of instruments

All instruments used in this study have demonstrated adequate psychometric properties in Portuguese child populations, and reliability estimates within our sample were satisfactory to excellent. For the teacher- and parent-reported measures, internal consistency coefficients ranged from α = 0.90 to 0.98 for peer relationships and α = 0.92 to 0.95 for self-management (SSBS; HCSBS). The SDQ externalizing scale showed adequate reliability (α = 0.76 at T1; α = 0.74 at T2), consistent with previous studies in Portugal. The internalizing measure (GAD-7) exhibited acceptable internal consistency (α = 0.73 at T1; α = 0.70 at T2). For inhibitory control, both tasks (HST; HTKS) are well-validated instruments with demonstrated construct validity in early childhood research, and performance scores were standardized within our sample. Together, these results confirm that the instruments showed strong reliability in the current sample and are supported by previous validation work documenting their factorial and construct validity.

2.4 Integration of social-emotional adjustment indicators and GNSS-derived behavioral measures

These SEA indicators were combined with behavioral measures derived from GNSS data during recess. GNSS data allowed us to explore how children's spontaneous movements and proximity behaviors relate to their regulatory and social-emotional development.

To compare how the magnitude of these behavioral changes differs between children with different SEA gains, the sample of 52 children was divided into two subgroups: High and Low SEA. This grouping allowed for the analysis of distinct associations between SEA profiles and children's spontaneous behavior during recess. To form the two groups, we used the ΔSEA scores (change from T1 to T2) of five key variables that had robust response rates among informants (parents, teachers, and the children themselves): self-management and peer relationships (teacher report), internalizing symptoms (child self-report), externalizing problems (parent report), and inhibitory control I (child task—HTKS). Due to missing data, the final cluster analysis included 33 children: 16 in the High SEA group and 17 in the Low SEA group.

3 Statistical analysis

Given the relatively small sample size and the non-normal distribution of several variables, non-parametric tests were selected as the most appropriate and robust option.

The social-emotional adjustment (SEA) at the beginning (T1) and end (T2) of the school year was compared using a Wilcoxon signed-rank test.

Effect sizes for non-parametric comparisons were calculated using Rosenthal's r, following the guidelines proposed by Fritz et al. (2012). Effect size magnitude was interpreted using conventional cut-off values (r = 0.10 for small, r = 0.30 for medium, and r = 0.50 for large effects; Cohen, 1988).

Individual changes in SEA variables were then calculated as simple difference scores (referred to as Change Scores, ΔSEA) and used in a two-step cluster analysis. This data-driven approach allowed us to classify children into groups with relatively higher vs. lower gains in social-emotional functioning (i.e., High and Low SEA groups). GNSS-derived behavioral metrics collected at both time points were compared within each group using Wilcoxon signed-rank test. Finally, between-group differences in change scores for were examined using Mann–Whitney U tests. All statistical analyses were conducted using IBM SPSS Statistics (version 28.0, IBM Corporation, Somers, New York, United States of America).

4 Results

Overall, social-emotional adjustment (SEA) showed positive development across the school year in the following dimensions: self-management, peer relationships, internalizing problems, and inhibitory control (Table 2).

Table 2. Changes in social-emotional functioning indicators between T1 and T2.

PR, Parent Report; TR, Teacher Report; T, Child Task; Med, Median; IQR, Interquartile Range; p, Z, and r values refer to within-sample comparisons between T1 and T2.

Z, Wilcoxon signed-rank test statistic; r, Rosenthal's effect size.

Wilcoxon signed-rank tests revealed significant improvements between the beginning (T1) and end (T2) of the school year in teacher-reported self-management (Z = −4.094, p < 0.001, r = 0.57), peer relationships reported by parents (Z = −2.794, p = 0.005, r = 0.39) and teachers (Z = −4.231, p < 0.001, r = 0.59), and inhibitory control I assessed with the HTKS task (Z = −4.337, p < 0.001, r = 0.60). Significant reductions were observed in internalizing problems (Z = −4.533, p < 0.001, r = 0.63), while no significant changes were found for externalizing behaviors across the full sample. According to established criteria, all effect sizes were large, except for parent-reported peer relationships, which showed a medium effect.

Spontaneous social behavior during recess was also examined longitudinally using GNSS-derived measures (Table 3). Wilcoxon tests indicated significant changes from T1 to T2 in distance from the group (Z = −3.708, p < 0.001, r = 0.51), time in proximity to peers (Z = −5.048, p < 0.001, r = 0.70), and time spent alone (Z = −4.709, p < 0.001, r = 0.65). All significant effects were of large magnitude.

Table 3. Comparison of GNSS-derived behavioral measures during recess between T1 and T2.

Med, Median; IQR, Interquartile Range.

p, Z, and r values refer to within sample comparisons between T1 and T2.

Z, Wilcoxon signed-rank test statistic; r, Rosenthal's effect size.

^a(%) indicates percentage of recess time.

A two-step cluster analysis based on five SEA change scores identified two distinct groups of children (Table 4). The silhouette coefficient indicated acceptable cluster quality (silhouette = 0.40). The High SEA group included 16 children (48.5%), and the Low SEA group comprised 17 children (51.5%). The strongest contributor to group membership was change in inhibitory control I, with higher mean change scores in the High SEA group (M = 13.69) compared to the Low SEA group (M = 0.12).

Table 4. Comparison of high and low social-emotional adjustment groups based on change scores (ΔSEA).

Δ indicates change scores calculated as the difference between T2 and T1.

Values represent median change scores.

TR, Teacher Report; SR, Self-Report; PR, Parent Report; T, Task.

To examine differences in developmental change between groups, mean change scores were compared using the Mann–Whitney U tests (Table 5). Significant between-group differences were found for teacher-reported self-management (U = 54.00, p = 0.003), teacher-reported peer-relationships (U = 41.00, p < 0.001), parent-reported externalizing problems (U = 43.50, p < 0.001), and inhibitory control I (HTKS; U = 13.50, p < 0.001). Among GNSS-derived spontaneous behavior indicators, a significant between-group difference in change scores was found only for time in proximity (U = 54.00, p = 0.015).

Table 5. Intra-group (T1–T2) and intergroup (Δ) comparisons of social-emotional and spontaneous behavioral variables in the high and low SEA groups.

Comparisons within groups (Within-Group p) refer to differences between T1 and T2. Comparisons between groups (Between-Group Δ p) refer to differences in change scores (Δ = T2–T1) between the High and Low SEA groups.

p < 0.05, p < 0.01, p < 0.001.

PR, Parent Report; TR, Teacher Report; SR, Self-Report.

(%) indicates percentage of recess time.

Med, Median; IQR, Interquartile Range.

^*significant differences between groups.

Within group analyses using Wilcoxon tests revealed distinct developmental trajectories (Table 5). In the Low SEA group, significant decreases over time were observed in internalizing problems (Z = −2.767, p = 0.006) and time alone during recess (Z = −2.442, p = 0.015), alongside significant increases in externalizing problems (Z = −2.773, p = 0.006) and time in proximity to peers (Z = −2.158, p = 0.031). In contrast, children in the High SEA group showed significant decreases in internalizing problems (Z = −3.309, p < 0.001), distance from the group (Z = −2.341, p = 0.019), and time spent alone (Z = −3.237, p < 0.001), as well as a significant increase in time in proximity to peers (Z = −3.351, p < 0.001), self-management (Z = −2.121, p = 0.034, parents; Z = −3.148, p = 0.002, teachers), peer relationships (Z = −3.148, p = 0.002, parents; Z = −3.442, p < 0.001, teachers), and in inhibitory control I (Z = −3.471, p < 0.001)..

5 Discussion

This study aimed to explore how spontaneous behavior during recess is associated with social-emotional adjustment (SEA) in first-grade children, using a longitudinal design and a combination of psychometric, task-based, and GNSS-derived measures. Consistent with a multidimensional view of SEA, encompassing self-management, peer relations, internalizing problems, externalizing behaviors, and inhibitory control, our findings show that both SEA and spontaneous behavior during recess change significantly over the school year and that their changes are positively aligned.

Consistent with H1, children demonstrated significant social-emotional gains throughout the school year, particularly in self-management, peer relations, and inhibitory control, accompanied by a reduction in internalizing problems. These findings are consistent with research highlighting the early elementary school years as a critical window for the maturation of emotional and relational skills (Domitrovich et al., 2017; Rademacher, 2022) and executive skills, which have positive associations with social interaction and cooperation (Benavides-Nieto et al., 2017). Such gains likely reflect children's increasing familiarity with school routines, sustained peer exposure, and growing opportunities to practice regulation and cooperative behaviors in everyday social situations, which are central mechanisms highlighted in developmental models of early adjustment.

Supporting H2, these developmental gains were reflected in observable changes in spontaneous behavior during recess: by the end of the school year, children spent more time close to their peers, engaged less frequently in solitary behaviors, and showed a decrease in their distance from the center of the group, indicating closer physical integration with the peer context. A systematic review by Hodges et al. (2022) supports these findings by highlighting positive associations between spontaneous recess behavior and the quality of peer relationships, school climate, and sense of belonging. Our longitudinal results extend this literature by showing that these associations are not only cross-sectional but also emerge as within-child developmental changes, suggesting that spontaneous peer proximity may be an indicator of SEA rather than merely concurrent correlate.

In contrast, this pattern is also consistent with studies showing that a preference for solitary play is related to antisocial behaviors and more conflictual peer relationships (Ooi et al., 2018; Rubin et al., 2009; Spinrad et al., 2004). Together, these findings reinforce the developmental significance of spontaneous peer engagement during recess as both a reflection and a driver of children's social-emotional functioning.

However, not all indicators derived from GNSS changed significantly. Distance to the nearest peers, spatial exploration, and group coordination showed no significant differences between time points or between SEA groups, suggesting that these dimensions of behavior may be more stable, limited by development, or less detectable using current GNSS-based measures. It is also possible that these indicators require more fine-grained temporal resolution or a larger sample to capture subtle variation, an issue noted in other GNSS-based studies with young children.

These longitudinal findings extend previous cross-sectional research (Nasri et al., 2022; Veiga et al., 2017a), showing that improvements in SEA are accompanied by increased group cohesion over time. This alignment between behavioral and emotional development reinforces the value of recess not only as free time but also as a context rich in opportunities to practice and develop social-emotional competencies. In particular, our use of GNSS-derived behavioral metrics offers new ecologically valid insights into children's actual interactions with peers, complementing traditional observation- and questionnaire-based methods, in line with Heravi et al. (2018).

Time spent near peers was positively associated with self-management and peer relations, while time spent alone was negatively associated with peer relations, echoing and extending previous work on the importance of developing closeness and inclusion in play environments (Ladd, 2006; Tsou et al., 2025; Veiga et al., 2017a). These results indicate that spontaneous and unstructured interactions, those initiated and maintained by the children themselves, can reflect and reinforce the development of essential social and emotional skills.

Given our findings, it is plausible to assume that the relationship works both ways. Increased opportunities for peer interaction, especially unstructured and self-initiated interaction, may promote the development of social-emotional skills. According to a transactional perspective (Sameroff, 2009), socially dynamic environments provide children with repeated opportunities to practice self-regulation, empathy, and cooperation. In this context, peer interaction plays a central role in emotional development, offering everyday situations that promote the recognition, expression, and regulation of emotions (Rieffe et al., 2015). As noted in integrative reviews (Hay et al., 2021; Ladd, 2005), these experiences are especially impactful when they occur in peer contexts that challenge children to navigate complex social cues. Although causal relationships cannot be confirmed in this observational study, our findings point to the value of developing peer closeness as a reflection and potential driver of social-emotional growth. The temporal associations observed suggest a dynamic interaction between peer interaction and SEA.

Addressing H3, the cluster analysis provided a more detailed perspective, revealing divergent developmental trajectories between children with High and Low SEA. Although both groups increased their peer proximity time across the school year, this change was more pronounced among children in the High SEA group. These children also showed a significant reduction in their distance to the center of the group, a possible marker of greater group cohesion. The stronger gains observed among High SEA children mirror previous findings showing that children with more advanced regulatory capacities tend to accumulate more positive social experiences over time (Eisenberg et al., 2010; Ladd and Troop-Gordon, 2003). Taken together, these behavioral changes suggest a “virtuous cycle”, in which children whose social-emotional skills improved most over time also became increasingly integrated into their peer group, thereby gaining more opportunities to strengthen self-regulation, cooperation, and emotional understanding (Eisenberg et al., 2010; Pellegrini et al., 2007).

This pattern aligns with research indicating that greater social engagement is positively associated with school adjustment and social-emotional functioning, whereas a preference for solitary play may signal adjustment difficulties (Ladd and Troop-Gordon, 2003; Ooi et al., 2018; Zhu et al., 2021). These dynamics are further supported by models of emotional socialization, which emphasize that emotionally rich peer contexts promote social-emotional competence (Rieffe et al., 2015; Hay et al., 2021), as well as transactional theories of development that highlight the reciprocal and evolving influences between the child and their social environment (Sameroff, 2009).

In contrast, children in the Low SEA group showed more modest behavioral changes. Although they also spent more time with peers and less time alone at the end of the year, this group showed an increase in externalizing behaviors, with no progress in self-management, peer relations, or inhibitory control, suggesting that their interactions with peers may not have been emotionally constructive or beneficial to development. These behavioral changes occurred without measurable gains in social-emotional functioning. This reinforces the idea that mere proximity does not guarantee meaningful social engagement or emotional growth. This divergence between children's behavior and SEA points to a potential cycle of exclusion, in which children with lower social-emotional adaptability may struggle to engage meaningfully with peers during recess, reinforcing social isolation or rejection by peers and impeding developmental progress (Coplan et al., 2006; Rubin et al., 2009).

This growing disparity between High and Low SEA groups raises important questions about equity in access to the social benefits of recess. Although recess is a shared context, its possibilities may be unevenly distributed depending on children's social-emotional skills. In some cases, the physical or social design of playgrounds may not be inclusive or emotionally accessible to all children, particularly those who struggle with self-regulation, peer engagement, or anxiety. Our reflections echo the studies by Nasri et al. (2022), who emphasized that playground environments should be designed and supervised in a way that considers children's individual differences. These findings underscore the importance of supporting peer interactions and designing socially inclusive play spaces for children who might otherwise remain on the margins. Without intentional adult support or facilitation and without welcoming environments that are adaptable to diverse social-emotional needs, some children may remain on the margins of peer networks, excluded from opportunities that their more sociable peers can easily access.

These findings underscore the importance of implementing inclusive practices to support peer interaction during unstructured moments. Strategies such as play-oriented interventions, peer buddy systems, and school-wide Social-emotional Learning programs can help promote more equitable social environments (Mayfield et al., 2017; Taylor et al., 2017). Just as adult facilitation is critical to creating emotionally safe and inclusive environments (Frank et al., 2018), the physical design of playgrounds must also be considered to ensure that they provide environments conducive to the development of children with different needs and genders (Andersen et al., 2015). Importantly, our GNSS findings can help schools identify when children consistently remain on the margins of peer groups, allowing for timely and targeted support. This ecological, data-driven monitoring could complement teacher observations and improve early identification of children at risk for social-emotional difficulties.

Together, this study contributes to a growing body of evidence (e.g., Nasri et al., 2022; Veiga et al., 2016) showing that spontaneous behaviors during recess are closely linked to children's social-emotional development. The use of GNSS technology offers an ecologically valid way to capture large-scale behavioral data discreetly and over time, allowing insights into real peer dynamics that traditional observational tools may miss.

While average trends at the group level suggest that recess supports positive developmental changes, subgroup analyses reveal growing disparities that highlight the need for targeted interventions. Ensuring that all children equally benefit from the social opportunities of recess requires thoughtful and inclusive approaches that account for individual differences in SEA.

Together, these findings support our hypotheses that social-emotional adjustment and spontaneous behavior at recess develop jointly over time, while also highlighting unequal access to social opportunities that may limit this growth for some children. By integrating longitudinal social-emotional functioning assessments with objective behavioral mapping, this study highlights how naturalistic peer interactions can serve as meaningful indicators of children's SEA and offers new tools for researchers and educators seeking to support all children more effectively.

5.1 Practical implications

These findings carry several practical implications for educators, school psychologists, and policymakers seeking to promote equitable social-emotional development in early schooling. First, the clear associations between SEA gains and increased peer engagement underscore the importance of supporting children's participation in meaningful, unstructured peer interactions. Recess should be viewed not merely as a break from instruction, but as a developmentally rich context in which children practice emotional and social skills. Schools might therefore prioritize adequate recess time and protect it from being reduced for disciplinary or instructional purposes.

Second, the differentiated trajectories observed between High and Low SEA groups highlight the value of early identification. GNSS-derived behavioral indicators, such as consistent distance from peers, limited group involvement, or increased solitary time, could serve as objective markers that complement teacher observations in identifying children who may be at risk for social-emotional difficulties. Integrating these ecological data into existing school monitoring systems could support more targeted and timely interventions.

Third, the findings suggest that simply being physically present with peers is not sufficient for children with lower SEA gains. These children may require intentional scaffolding to help them initiate and sustain emotionally constructive peer interactions. Approaches such as peer-buddy systems, cooperative play interventions, and explicit SEL programs (Taylor et al., 2017; Mayfield et al., 2017) may be particularly beneficial for children who remain socially peripheral. Opportunities to practice turn-taking, problem solving, and emotion regulation could support more meaningful engagement.

Finally, the study highlights the need for inclusive and socially supportive recess environments. Research on inclusive playgrounds further emphasizes that the physical and social design of play spaces can meaningfully shape children's social engagement, especially for children with special needs (Massey et al., 2021; Moreira et al., 2023; Rieffe et al., 2025; Tsou et al., 2025). Ensuring that playground environments accommodate diverse emotional and social needs is essential for enabling all children, not only those who are already socially skilled, to benefit from the developmental opportunities that recess affords.

5.1.1 Conclusions and limitations

This multidimensional longitudinal observational study offers new insights into the dynamic relationship between children's social-emotional adjustment (SEA) and their spontaneous behavior during the first year of elementary school. By combining psychometric data from multiple sources (parents, teachers, and children) with GNSS-derived measures of peer proximity and spatial behavior during recess, we demonstrate that social-emotional adjustment and spontaneous behavior develop together and reflect each other over time. The use of GNSS technology provided ecologically valid and discreet access to children's natural behavior in social contexts, reinforcing its potential as a research tool for studying peer interactions at scale.

The comparison between high and low SEA groups revealed distinct behavioral trajectories, suggesting that children with stronger social-emotional skills become more integrated into peer networks over time, while those with lower SEA may remain on the periphery. These patterns raise important considerations for equity and inclusion in recreational settings and highlight the need for adult-facilitated and design-sensitive approaches to promote the involvement of all children.

Despite its contributions, this study is not without limitations. The relatively small sample size for subgroup analyses and the reliance on only two time points limit the generalizability and granularity of the results. In addition, potential seasonal and spatial constraints, as well as issues of GNSS accuracy in dense playground environments, should be addressed in future research.

It is important to note that GNSS-based proximity data capture physical closeness but not the quality of peer relationships or friendship bonds; therefore, interpretations based on these data should be made with caution. In addition, because each class was monitored separately and only with its own classmates, interactions with children from other classes were not included in the data collected. Future studies involving mixed-class recess periods or sociometric methods could help clarify children's wider peer networks.

Future studies could include mid-year assessments to capture non-linear trajectories of SEA and incorporate collective or context-specific measures to better understand subgroup dynamics. Intervention studies integrating peer-guided interaction strategies and social-emotional learning programs would help clarify whether promoting physical proximity between children with different SEA profiles can improve developmental outcomes.

Theoretically, these findings support transactional perspectives of development, showing that children's peer interactions and social-emotional skills evolve in reciprocal and mutually reinforcing ways. Practically, these results highlight the value of using objective behavioral indicators, such as GNSS-based proximity measures, to identify children who may benefit from early social-emotional support and to guide the design of inclusive recess environments that foster participation for all children.

Together, these findings emphasize the relevance of recess as a developmental context and highlight the value of combining behavioral technologies with inclusive practices to better understand and support children's social-emotional growth.

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Footnotes

Edited by: Yiying Teng, Shanghai Pudong Vocational and Technical College, China

Reviewed by: Ana Baltazar, National Autonomous University of Mexico, Mexico

Ebtesam Rababah, Yarmouk University, Jordan