Personality heterophily and friendship as drivers for successful cooperation.

Cooperation is widespread and arguably a pivotal evolutionary force in maintaining animal societies. Yet, proximately, what underlying motivators drive individuals to cooperate remains relatively unclear. Since 'free-riders' can exploit the benefits by cheating, selecting the right partner is paramount. Such decision rules need not be based on complex calculations and can be driven by cognitively less-demanding mechanisms, like social relationships (e.g. kinship, non-kin friendships, dyadic tolerance), social status (e.g. dominance hierarchies) and personalities (social and non-social traits); however, holistic evidence related to those mechanisms is scarce. Using the classical 'loose-string paradigm', we tested cooperative tendencies of a hierarchical primate, the long-tailed macaque (Macaca fascicularis). We studied three groups (n = 21) in their social settings, allowing partner choice. We supplemented cooperation with observational and experimental data on social relationships, dominance hierarchies and personality. Friendship and dissimilarities in non-social 'exploration' and 'activity-sociability' personality traits predicted the likelihood of cooperative dyad formation. Furthermore, the magnitude of cooperative success was positively associated with friendship, low rank-distance and dissimilarity in the activity-sociability trait. Kinship did not affect cooperation. While some findings align with prior studies, the evidence of (non-social) personality heterophily promoting cooperation may deepen our understanding of the proximate mechanisms and, broadly, the evolution of cooperation.

A cognitive script perspective on how early caregiving experiences inform adolescent peer relationships and loneliness: A 14-year longitudinal study of Chinese families.

Leveraging data from a longitudinal study of Chinese families (n = 364), this research aims to understand the role of secure base script knowledge as a cognitive mechanism by which early caregiving experiences inform adolescents' friendship quality and feelings of loneliness. Results showed that observed maternal sensitivity at 14 and 24 months old was negatively associated with adolescents' self-reported conflicts with close friends (ß = -0.17, p = 0.044) at 15 years old, and this association was partially mediated by their secure base script knowledge assessed at 10 years old. Further, secure base script knowledge moderated the link between adolescents' friend conflict and feelings of loneliness (ß = -0.15, p = 0.037). The results support a cognitive script perspective on the association between early caregiving experiences and later socio-emotional adjustment. Furthermore, this study adds to the developmental literature that has previously focused on more stringent and authoritarian aspects of parenting in Chinese families, thereby contributing to our understanding of how sensitive and supportive parenting practices contribute to socio-emotional development outside of Western contexts. RESEARCH HIGHLIGHTS: Maternal sensitivity during infancy and toddlerhood has a long-term association with adolescents' friendship quality and adolescents' secure base script partially explains the association. First evidence to demonstrate that the secure base script in attachment relationships mediates the association between early maternal caregiving and socio-emotional development in Chinese adolescents. Adolescents lacking secure base script knowledge are particularly vulnerable to feelings of loneliness when facing high levels of conflict in close friendships.

Exploring Within-Gender Differences in Friendships Using an Online Social Network.

People tend to befriend others similar to themselves, generating a pattern called homophily. However, existing studies on friendship patterns often rely on surveys that assess the perspective of relatively few participants on their friendships but do not measure actualized friendship patterns. Here, we used data from a large Slovakian online social network to assess the role of gender, age, and body mass index (BMI) in same-gender online connections among more than 400,000 users. We found that age and BMI homophily occurred in both men's and women's same-gender connections, but somewhat more strongly among men's. Yet, as women diverged in BMI, their connections were less likely to be reciprocated. We discuss how the evolutionary legacy of men's coalitional competition (e.g., warfare) and women's mating competition or recruitment of allocare providers might contribute to these patterns in modern same-gender relationships. For example, men's engagement in physical activities may lead to similar formidability levels among their same-gender peers. Altogether, our findings highlight the importance of trait similarity to same-gender friendship patterns.

The influence of friendships on the mental health of maltreated youth: A pre-registered systematic review using a developmental psychopathology perspective.

Friendships are a potential factor that influence maltreated children's risk for psychopathology. This systematic review examined (1) how friendships influence the association between child maltreatment and psychopathology and (2) developmental differences in how friendships influence this association. Four databases were searched. Inclusion criteria were primary study, quantitative, measures of maltreatment and friendship up to the age of 18 years, measures of psychopathology up to the age of 24 years, and a non-maltreated sample. Exclusion criteria were qualitative, reviews or meta-analyses, no distinction between maltreatment and other trauma, and no differentiation between friendships and other support. Risk of bias was assessed. Data were narratively synthesized. Two hundred thirty-five articles were retrieved for full review. Fourteen met inclusion criteria (N = 98,676 participants). Eleven of the fourteen studies found that some aspect of friendships influenced the association between maltreatment and psychopathology, with positive qualities generally decreasing risk and negative qualities increasing risk for psychopathology. However, peer support exacerbated maltreated children's risk for psychopathology in two studies. Only three studies assessed friendship prior to adolescence, which precluded conclusions regarding developmental differences. Future research should consider developmental differences and use findings and validated measures from the peer relations literature to better understand how friendships influence maltreated youth's vulnerability to psychopathology.

A healthy balance: the ratio of social support-to-demands is associated with metabolic syndrome.

Metabolic syndrome is associated with increased risk for negative health events, decrements in quality of life, and greater health costs. The current study sought to identify whether the ratio of social support to social demands across multiple relationship types (spouse, friends, children, or other family members) were associated with concurrent metabolic syndrome in a nationally representative sample of US adults ages 32-40. Results indicate that the ratio of total social support to social demands was associated with a greater likelihood of meeting criteria for metabolic syndrome, even after statistically controlling for the effects of race, ethnicity, sex, age, income, and prior metabolic syndrome. When considering the relative contributions of each relationship type, greater support relative to demands from friends was the only relationship type that was significantly independently associated with lower likelihood of metabolic syndrome. Although not statistically significant, a trend-level negative association with spousal support/demands emerged, as did a trend-level positive association with support/demands from children. Taken together, the current study reaffirms the relevance of considering social support and demands with regards to metabolic syndrome and highlights the ways in which specific relationships may differentially relate to health risk.

Recent stressful life events and identity development in emerging adults: An examination of within-person effects.

OBJECTIVE: To examine longitudinal associations among stressful life events and identity processess in emerging adults while accounting for within-person and between-person effects. BACKGROUND: Theoretical perspectives suggest that stressful life events may impact one's identity (i.e., coherent sense of self), but few studies have considered how changes in stressful life events are associated with changes within an individual's identity development over time (within-person effects). METHODS:  Recent stressful life events (i.e., academic problems, friendship problems, romantic problems, and time pressure) and the processes through which identity develops (e.g., exploring in breadth and depth) were examined longitudinally (T1-T3) in a sample of emerging adults (N = 1125, Mage = 17.96 years). RESULTS: Random-intercept cross-lagged modeling demonstrated that at the between-person level, emerging adults with greater academic and friendship problems, as well as more time pressures (relative to their counterparts), tended to engage in greater ruminative exploration. Further, those with more academic problems tended to demonstrate weaker commitment-making and exploration in breadth and depth (relative to their counterparts). Within-person increases in romantic problems predicted lower commitment-making and higher ruminative exploration over time. CONCLUSION: Findings suggest that romantic problems may predict within-person changes in identity processes, whereas academic problems, friendship problems, and time pressure may be more concurrently related to identity development.

Influence of perceived peer behavior on engagement in self-damaging behaviors during the transition to university.

As students transition to university, they experience significant social changes that can affect their behaviors, including self-damaging behaviors like disordered eating, problematic alcohol/drug use, suicidal thoughts, and non-suicidal self-injury (NSSI). Building on prior work, we examined the associations between (1) perceptions of peers' engagement in self-damaging behaviors predicting one's own subsequent engagement in such behaviors (i.e., socialization) and (2) one's own engagement in self-damaging behaviors predicting perceptions of peers' subsequent engagement in such behaviors (i.e., selection). We also examined whether these associations were moderated by the source of influence (close peer/acquaintance) and degree of social disconnection experienced by the student. First-year university students (N = 704) were asked to complete seven monthly surveys. Multilevel models indicated that when students perceived their close peers had engaged in NSSI or suicidal thinking, they had seven times greater odds of future engagement in the same behavior, implying that socialization increases the risk of these behaviors among university students. Perception of acquaintances' NSSI also predicted greater odds of a student's own NSSI the following month. Social disconnection increased the likelihood of matching own behaviors to perceptions of acquaintances' alcohol abuse, highlighting the importance of fostering connections/mentors to reduce self-damaging behaviors on college campuses. Furthermore, when students engaged in alcohol abuse, they had almost four times greater odds of reporting that their acquaintances abused alcohol the following month, emphasizing the importance of the wider social network in alcohol use behaviors.

Friendship attachment style, intolerance of uncertainty, and psychological distress among unaccompanied immigrant minors in times of COVID-19.

INTRODUCTION: This cross-sectional study used a convergent parallel mixed-method design to investigate friendship attachment style, intolerance of uncertainty, and psychological distress among unaccompanied immigrant minors (UIMs) during the second wave of the COVID-19 pandemic in Italy. METHOD: Participants were 80 male UIMs (Mage = 17 years, standard deviation = 0.84) hosted in residential care communities. Individual interviews comprising questionnaires and open-ended questions assessed the constructs of interest. Qualitative data were analyzed through thematic content analysis, whereas descriptive statistics and regression analysis were computed on quantitative data. RESULTS: Several UIMs mentioned positive relationships with peers, but more than half also felt reluctant to trust others and build new friendships due to events experienced before and during migration. However, in quantitative data, 69% identified themselves with the secure friendship attachment style. Regarding intolerance of uncertainty, participants expressed feelings of worry about the pandemic, but also emphasized their resources in terms of confidence, optimism, and planning skills, as well as being accustomed to uncertainty; indeed, levels of this variable were low-to-medium. In regression analysis, insecure attachment and higher intolerance of uncertainty were each associated with greater psychological distress. Moreover, psychological distress was lower among securely attached UIMs with low (vs. high) levels of intolerance of uncertainty. CONCLUSION: The findings suggest that, even in conditions of societal insecurity, UIMs display resilience and employ effective coping strategies; however, a lack of trust in peer relationships and the inability to tolerate uncertainty may undermine their psychological adjustment. Implications for developmental theory and practice are discussed.

Communication modality matters: Co-rumination via in-person versus digital modalities has different prospective associations with depression and friendship quality.

INTRODUCTION: Co-rumination is an interpersonal emotion regulation strategy in which negative feelings and problems are discussed perseveratively with another person. Although co-rumination is salient in adolescence, research to date has focused on co-rumination occurring in person and has not kept pace with the surge in digital communication that begins in adolescence. This study examined the degree, associations among, and consequences (i.e., depressive symptoms, and friendship quality) of adolescents' co-rumination via in-person, text, social media, and phone modalities. METHODS: Adolescents (n = 109; 51 girls, 57 boys, 1 nonbinary; Mage = 12.83 years) residing in Canada, completed self-report questionnaires on co-rumination, depressive symptoms, and friendship quality for up to 2 years. RESULTS: Adolescents engaged in co-rumination across all modalities, particularly in-person. Findings indicated a negative association between in-person co-rumination at baseline and in-person co-rumination over time. Whereas less text co-rumination was associated with increased depressive symptoms over time, greater phone co-rumination was associated with increased depressive symptoms over time. Although greater in-person co-rumination was positively associated with friendship quality concurrently, it was negatively associated with friendship quality prospectively. CONCLUSIONS: Taken together, co-rumination outcomes may vary depending on communication modality. Implications for adolescents' mental and social wellbeing are discussed.

The coevolution of bullying and friendship networks.

The coevolution of bullying and friendship networks and the moderating effects of classroom bullying popularity norms were examined in a sample of 965 students (52.1% boys) in 22 fourth- and fifth-grade classes. Longitudinal social network analysis showed that children were more likely to bully their friends' victims (bully influence effect) and to be bullied by their friends' bullies (victim influence effect); two children bullying the same child were likely to be friends (bully selection effect), and two victims bullied by the same child were likely to be friends (victim selection effect). Bullying popularity norms served as moderators, and the bully selection effect was significant weaker in the context of low bullying popularity norms. This study adds understanding of bullying as a group process and provides implications for preventing school bullying.

Internet addiction and depressive and anxious symptoms among Chinese rural left-behind adolescents: Mediating roles of resilience and friendship quality.

BACKGROUND: Rural left-behind adolescents are more vulnerable to Internet addiction and depressive and anxious symptoms due to the lack of family support and parental supervision. This study was the first to investigate the longitudinal relationships between Internet addiction and depressive and anxious symptoms and to examine the mediating roles of resilience and friendship quality in rural left-behind adolescents. METHODS: Included in this study, which was from a longitudinal study conducted five times over 2 years, were 1001 rural left-behind adolescents. The internationally used scales for depressive and anxious symptoms, Internet addiction, resilience and friendship quality were administered. A structural equation model was used for analysis. RESULTS: The prevalence of Internet addiction, depressive and anxious symptoms among rural left-behind adolescents were 17.7%, 35.8% and 27.6%, respectively. Internet addiction predicted the later depressive and anxious symptoms (ß = 0.200, 95% confidence interval [CI]: 0.116-0.274 and ß = 0.263, 95% CI: 0.188-0.330). Resilience acted as an independent mediator in the relationships between Internet addiction and depressive and anxious symptoms (ß = 0.037 and 0.034, P < 0.01). Resilience and friendship quality played a chain-mediating role on the longitudinal relationships between Internet addiction and depressive and anxious symptoms (ß = 0.011 and 0.010, P < 0.001). The mediating effects accounted for 24.0% and 16.7% of the total effects, respectively. CONCLUSION: Resilience and friendship quality play an independent or chain-mediating role in longitudinal relationships between Internet addiction and depressive and anxious symptoms. The findings inform targeted intervention strategies to improve the mental health of left-behind adolescents.

Longitudinal Associations Between Friendship Ethnic/Racial Composition and Ethnic/Racial Identity: The Role of School Ethnic/Racial Diversity.

Schools and friendships represent important but distinct contexts for adolescent identity development. However, research has yet to explore the long-term interplay between these factors on ethnic/racial identity (ERI). This study included a sample of 640 adolescents from 9 public high schools in a diverse United States metropolis (Mage = 14.50, SD = 0.67; 44% Asian, 20% Black, 36% Latinx; female = 68%, male = 32%, non-binary = 0%). Latent growth curve modeling was conducted to investigate longitudinal associations in friendship ethnic/racial composition and ERI exploration. From the 9th-11th grades, same-race friends and ERI exploration increased linearly whereas friendship ethnic/racial diversity decreased linearly. Adolescents attending more ethnically/racially diverse schools maintained more ethnically/racially diverse friends over time but did not differ in changes in ERI exploration compared to adolescents in less diverse schools. There was no association between the rates at which adolescents' friendship ethnic/racial composition and ERI changed over time. More ethnically/racially diverse friends in the 9th-grade predicted faster increases in subsequent ERI exploration. The findings highlight important differences in the roles of friendship and school contexts on ERI, suggesting that friendship ethnic/racial diversity, but not school ethnic/racial diversity, facilitated ERI exploration over time. School ethnic/racial diversity did facilitate a slower decline in friendship ethnic/racial diversity, emphasizing the importance of school integration.

The Relation between Residential Mobility and Internalizing and Externalizing Problems in Adolescence: The Role of Subjective Moving Experience, Gender, and Friendship Quality.

Adolescent residential mobility can be a stressful life event, potentially aggravating internalizing or externalizing problems. However, the longitudinal effects of residential mobility are understudied and may be context-dependent. This study investigates the longitudinal associations between adolescent residential mobility and internalizing and externalizing problems. Additionally, this study examines for whom residential moves are most detrimental by including subjective moving experience, gender, and friendship quality before the move as moderators. Longitudinal data from 2,029 adolescents (51% female) from the TRacking Adolescents' Individual Lives Survey (TRAILS) were used (Mage [SD] at T1 = 11.1 [0.55], T2 = 13.6 [0.52], and T3 = 16.3 [0.70]). Results from stepwise multi-level random-effect models showed that adolescents who experienced an unpleasant move remained stable in internalizing problems, while others decreased over time. Adolescents who moved increased stronger in externalizing problems than adolescents who did not move, independent of whether they experienced the move as unpleasant. Gender and friendship quality before the move did not moderate the relation between residential mobility and internalizing or externalizing problem development. These results emphasize that residential moves in adolescence, especially when experienced as unpleasant, can have long-lasting negative effects on adolescent development.

Friendship Homophily Trajectories among Asian American Youth from High School to College.

Friendship racial homophily, the tendency to form friendships with individuals who share the same racial background, is a normative developmental phenomenon that holds particular significance for youth of color in a racialized society. Yet, there exists a paucity of longitudinal research elucidating the stability and change of friendship racial composition across developmental span. This study aimed to examine the friendship racial homophily trajectories over a six-year period encompassing four time points. The sample comprised 437 Asian American youth (MAge = 16.52, SDAge = 1.36, 53% female), with 197 Filipino and 240 Korean participants. Using logistic multilevel modeling analyses, it was found that both Filipino and Korean American youth demonstrated an increase in friendship racial homophily from high school to college, but that Filipino youth overall reported lower levels of racial homophily compared to their Korean counterparts. The study findings also pinpointed several influential factors impacting these trajectories, including proficiency in heritage languages, ethnic identity, and encounters with racial discrimination from both White Americans and other People of Color. These results highlight the continuous evolution of friendship racial composition from high school to college and emphasize the crucial role of ethnic identity and experiences of discrimination in influencing these dynamics, with ethnic identity exerting more enduring effects and experiences of discrimination showing more situational impacts on the levels of racial homophily.

Shaping Citizenship in the Classroom: Peer Influences on Moral Disengagement, Social Goals, and a Sense of Peer Community.

Despite the important role of peers in the social process of classroom citizenship, the peer influence related to moral disengagement, social goals, and a sense of peer community remain unclear. To this end, it was examined to what extent youth become similar to their friends in moral disengagement, social goals, and a sense of peer community. Participants were 283 South Korean third to sixth graders (Mage = 9.60 years, SD = 0.97; 51.6% girls) who completed an online survey for moral disengagement, social goals, the sense of peer community and friendship network across the beginning (Time 1) and end (Time 2) of the school semester (September to December). Longitudinal social network analyses indicated that youth became more similar to their friends concerning moral disengagement and a sense of peer community, but did not select friends based on these aspects. The strength of these influence effects varied in terms of different levels of these aspects. Specifically, youth were more likely to become similar to their friends at lower levels of moral disengagement. Youth tended to be similar to the friends' level of sense of peer community. This tendency was relatively strong at the lowest and the highest levels of a sense of peer community. Future research should address the role of friendship in shaping classroom citizenship and the importance of classroom daily teaching practice in youth citizenship development.

The Social Processes of Excessive Online Gaming Homophily: Peer Selection or Influence?

Adolescents who befriend online game using peers may be at risk for initiated and continued excessive game use (online gaming use homophily). The present article examined how adolescents' severity of online gaming use related to their friends' online gaming behavior bi-directionally across a semester (peer selection or peer influence effect). Students from two universities completed three waves of online surveys within four and a half months (N = 3079; 33.6% female; Mage = 19.16; SD = 0.97). Random-intercepts, Cross-Lagged Panel Model (RI-CLPM) analyses revealed that peer selection and peer influence both promote online gaming use homophily in adolescents' friendship groups. Furthermore, participants were more likely to form new friendships with peers exhibiting similar online gaming behavior as their behavior, subsequently reinforcing their online gaming use behaviors within these relationships. These social processes may exhibit a time lag among girls, which needs to be confirmed through longer-term follow-up. In general, findings suggest that effective prevention programs targeting excessive online gaming should not only focus on promoting social influence skills but also consider the structure of peer environments.

How do people with intellectual disabilities understand friendship? A systematic meta-synthesis.

BACKGROUND: Previous systematic reviews of the relationships of people with intellectual disabilities have included consideration of intimate relationships. In this paper, we report a systematic review of papers describing friendship only. METHOD: A systematic qualitative meta-synthesis of the research exploring experiences of friendship as reported by people with intellectual disabilities. RESULTS: Seven papers met the inclusion criteria for analysis. Three superordinate themes were identified. (1) Reciprocity, 'Someone who helps me, and I help them'. (2) The building blocks of friendships, 'I can tell her some secrets'. (3) Managing friendship difficulties, 'In real life it's much harder'. CONCLUSION: People with intellectual disabilities value friendship and actively engage in reciprocal exchanges. We explore the strengths and limitations of current research, clinical implications, and directions for future research.

Psychological and social outcomes of befriending interventions for adults with intellectual disabilities: A systematic review.

BACKGROUND: Befriending is an intervention intended to provide companionship and support to socially isolated populations. This review aimed to understand the key characteristics and psychological and social outcomes of befriending interventions for adults with intellectual disabilities. METHODS: Systematic searches of electronic databases (PsycINFO, MedLine and Web of Science) identified 11 studies for inclusion. A narrative synthesis of the findings was completed, along with critical appraisal of study quality. RESULTS: Increased community participation, positive changes to social networks and mood were frequently reported outcomes for befriendees. Increased knowledge, new experiences and opportunities to 'give back' were most reported for befrienders. CONCLUSIONS: The review highlighted that existing research in this field is limited in scope and methodologically diverse. Future research should focus upon the effectiveness and long-term impact of befriending interventions, understanding the mechanisms of change, and eliciting the views of people with intellectual disabilities on their experiences.

Understanding experiences of 'Gig Buddies': A befriending scheme for people with intellectual disabilities.

BACKGROUND: Research into befriending for people with intellectual disabilities is limited. This study aimed to explore the impact, mechanisms of change, and limitations of a befriending scheme for adults with intellectual disabilities and/or autism. METHODS: Participants were recruited using convenience sampling. Thirteen individuals with intellectual disabilities and/or autism were interviewed and data thematically analysed. RESULTS: Four themes were generated: 'Something fun for me'; 'A good connection'; 'Increasing independence'; and 'A life less quiet'. Befriending had direct benefits through the activities undertaken and the befriending relationships themselves being fun and reducing isolation. Befriending facilitated belonging, improved access to mainstream activities, and fostered independence by providing safety and support. The importance of shared interests and external support for the relationship was highlighted. CONCLUSIONS: Positive outcomes of befriending were found, supporting existing literature and revealing new information from the voices of participants with intellectual disabilities themselves.

Attitudes toward persons with epilepsy as friends: Results of a factorial survey.

OBJECTIVE: Discrimination against persons with epilepsy (PWEs) may persist. The aim of this study was to examine whether epilepsy is an obstacle to desired friendship. METHODS: A factorial survey (vignettes), which is less biased by social desirability, was applied to PWEs, their relatives, and lay persons. The vignettes described a person who was varied by the dimensions of age (younger, same age, older), gender (male, female), disease (healthy, mild epilepsy, severe epilepsy [generalized tonic-clonic seizures], diabetes), origin (German, non-German), contact (phone/internet, activities at home, activities outside), frequency of contacts (weekly, monthly), and distance (around the corner, 10 km away). Respondents rated their willingness to befriend the person on a 10-point Likert scale. Multivariate regression determined the contribution of each dimension on the judgment. RESULTS: Participants were 64 PWEs (age = 37.1 ± 14.0 years), 64 relatives of PWEs (age = 45.1 ± 13.6 years), and 98 controls without contact with PWEs (age = 24.4 ± 10.1 years). Controls were less interested in a friendship with a PWE with mild epilepsy (-3.4%) and even more avoided PWEs with severe epilepsy (-11.7%), whereas in PWEs with tonic-clonic seizures, a mild form of epilepsy was actually conducive to friendship (+7.0%). Controls preferred females (+5.0%) and disliked younger people (-12.3%) and contacts via the internet or telephone (-7.3%). PWEs were also less interested in younger people (-5.8%), and relatives of PWEs had a lower preference for friendships with longer distance (-2.3%). SIGNIFICANCE: PWEs still suffer from a risk of social avoidance, and this becomes more evident with generalized motor seizures.