No full-text available
To read the full-text of this research,
you can request a copy directly from the author.
The Anatomy of Friendship
Abstract
Friendship is the single most important factor influencing our health, well-being, and happiness. Creating and maintaining friendships is, however, extremely costly, in terms of both the time that has to be invested and the cognitive mechanisms that underpin them. Nonetheless, personal social networks exhibit many constancies, notably in their size and their hierarchical structuring. Understanding the processes that give rise to these patterns and their evolutionary origins requires a multidisciplinary approach that combines social and neuropsychology as well as evolutionary biology.
... For instance, Gonçalves et al. [23] analyzed 1.7 million Twitter users' conversation data across six months and found that these users had a maximum of 100-200 stable social relationships on Twitter, which is generally consistent with Dunbar's Number. Similar results were found on largescale mobile phone data [24] and email data [25], lending added support to Dunbar's Number across several online mediums [26][27][28]. ...
... [24]). To be sure, follow-up research has also recognized that there is wide variance around the mean sizes of Dunbar's network layers [28]. Moreover, other researchers have argued that network size may be larger in online ...
... Reflecting on Dunbar's Numbers contexts, thus questioning the numerical limits enumerated above (e.g., [13,14]). Such concerns follow research revealing significant variations in personal network size (e.g., [28,37]), as well as structure ) and perception (e.g., [38,39]). These lines of work not only show that people differ in how they construct and interact with their networks, but also suggest that their perceptions about how they allocate social energy are likely to vary considerably. ...
Past studies have investigated the variability in how people engage with their personal networks, yet less is known about how people perceive their energy allocation to different ties. Drawing on an online survey sample (N = 906), we tested whether subjective perceptions of energy allocation conform to so-called Dunbar’s Number(s). In addition, we evaluated the predictive roles of Big Five personality traits and self-esteem while controlling for differences in network structure. Results revealed significant heterogeneity in perceived energy allocation to different layers of personal networks (i.e., inner 5 vs. middle 15 vs. outer 150 relationships). In contrast to expectations, extraversion was not associated with perceived energy allocation, whereas self-esteem was associated with greater energy allocation to the middle (vs. inner) network layer. Our findings add to our knowledge of how people perceive relationship maintenance across their personal networks, along with the links to key psychological traits. More broadly, the findings suggest that more attention should be paid to psychological implications of the middle layer of personal networks. To conclude, we discuss the importance of studying individual differences in how people prioritize – and reflect on – different relationships in their networks.
... The latter includes both mentalizing (understanding others' intentions) and self-control (the ability to inhibit prepotent actions). [17][18][19] Inhibition allows individuals to coordinate their activities, as well as to avoid destabilizing relationships unnecessarily by pursuing their own short-term selfish interests. 17 Mentalizing is central to this: to avoid responding inappropriately to others' actions, we need to understand their motives and intentions. ...
... [17][18][19] Inhibition allows individuals to coordinate their activities, as well as to avoid destabilizing relationships unnecessarily by pursuing their own short-term selfish interests. 17 Mentalizing is central to this: to avoid responding inappropriately to others' actions, we need to understand their motives and intentions. Both mentalizing and inhibition are much more cognitively demanding than is often supposed, as well as involving dedicated neural systems in the brain (inhibition 7,18,19 ; mentalizing [20][21][22][23][24][25] ). ...
... The core to primate and human social life, then, is friendshipspersonalized relationships between two individuals based on a deep emotional bond. 17 In anthropoid primates, the bonding process is created by social grooming. Social grooming, as I shall show below, triggers β-endorphin release, and this in turn creates a deep sense of belonging. ...
Humans, like all monkeys and apes, have an intense desire to be social. The human social world, however, is extraordinarily complex, depends on sophisticated cognitive and neural processing, and is easily destabilized, with dramatic consequences for our mental and physical health. To show why, I first summarize descriptive aspects of human friendships and what they do for us, then discuss the cognitive and neurobiological processes that underpin them. I then summarize the growing body of evidence suggesting that our mental as well as our physical health and wellbeing are best predicted by the number and quality of close friend/family relationships we have, with five being the optimal number. Finally, I review neurobiological evidence that both number of friends and loneliness itself are correlated with the volume of certain key brain regions associated with the default mode neural network and its associated gray‐matter processing units.
... The authors suggested that the cognitive representations of romantic partners are unique in content and use, chronically accessible, and serve emotion-regulatory functions. In another study, differences between closer individuals (layers 1-3) and less close individuals (layers [4][5] influenced activity patterns in the medial prefrontal, inferior frontal and medial parietal cortices, and the temporoparietal junction 20 . Two other studies 21,22 investigated real-world social networks (layers 1-5) as a whole and found that activity in the temporoparietal junction, the posterior lateral temporal lobe and the retrosplenial cortex was correlated with the personal distance to individuals within these networks. ...
... The vast majority of one's social cognitive efforts are dedicated to individuals in the support clique 54 . Furthermore, social reward provided by individuals in this social layer significantly surpasses reward by individuals in all other social layers and has been shown to be crucial to emotional well-being, stress reduction and healthy social interaction 4,55,56 . The disproportional cognitive effort and social reward associated with the support clique may account for its extensive representation in the brain despite its small size ( Supplementary Fig. 1). ...
... For example, one participant may consider the frequency of contact to be a major factor in identifying close friends, while for another, this factor may hold little significance. However, this general measure of psychological distance has proven itself reliable in many studies 4,11,20,90 . To obtain valid representations of participants' social networks, we did not provide exact definitions for each social layer but instead allowed them to choose the definitions that best fit their network. ...
Healthy social life requires relationships in different levels of personal closeness. Based on ethological, sociological, and psychological evidence, social networks have been divided into five layers, gradually increasing in size and decreasing in personal closeness. Is this division also reflected in brain processing of social networks? During functional MRI, 21 participants compared their personal closeness to different individuals. We examined the brain volume showing differential activation for varying layers of closeness and found that a disproportionately large portion of this volume (80%) exhibited preference for individuals closest to participants, while separate brain regions showed preference for all other layers. Moreover, this bipartition reflected cortical preference for different sizes of physical spaces, as well as distinct subsystems of the default mode network. Our results support a division of the neurocognitive processing of social networks into two patterns depending on personal closeness, reflecting the unique role intimately close individuals play in our social lives.
... ), (2) this relationship actually consists of a set of four grades arranged in a fractal series that explains the multilevel structure of primate (and human) social systems (Zhou et al. 2005;Hill et al. 2008;Sutcliffe et al. 2012;Dunbar and Shultz 2021), (3) the grades differ in group size, brain size, social complexity, cognitive competences, and ecological context (Dunbar and Shultz 2021;Dunbar 2024), (4) the core group size of ~150 for modern humans predicted by the regression equation for the social brain relationship (Dunbar and Shultz 2023) has been confirmed by 23 studies of personal social networks and ethnographic communities (median sample size 5457 individuals, largest sample 61 million) from a wide range of cultures and historical periods over the last 2000 years (Dunbar 2020), (5) this grouping is nested within a fractal series of network layers (a Dunbar Graph) with very specific values (1.5, 5, 15, 50, 150, 500, 1500, 5000) that we find in the face-to-face world (Bird et al. 2019;Dunbar 2020;Wang et al. 2020), on digital social media (telephone calling, texting, Facebook and twitter) Dunbar et al. 2015;MacCarron et al. 2016) and even online multiplayer game environments (Fuchs et al. 2014), (6) this fractal series forms a set of 'attractors' in the form of criticalities (or optima) in the efficiency of information flow in networks (though we don't understand why) (West et al. 2020(West et al. , 2023), (7) these same numbers reappear in both the distribution and their internal structure of primate, carnivore and cetacean social groups (Hill et al. 2008;Dunbar and Shultz 2021;Dunbar 2024), (8) at least in humans, the fractal structure is the product of a trade-off between the time costs required to maintain different kinds of relationships and the benefits these provide (Sutcliffe et al. 2012;Tamarit et al. 2018) and (9) although the population average for human personal social networks is always ~150, there is considerable variation between individuals due to gender, age, personality and social circumstances (Roberts et al. 2008;Dunbar 2018;Tamarit et al. 2018). ...
... In addition, (10) upwards of 20 neuroimaging studies of humans and three of monkeys have shown that the size of an individual's personal social network is highly correlated with the size of core elements in its neocortex (prefrontal cortex, temporo-parietal junction and temporal pole, plus the subcortical amygdala and cerebellum, and the massive white matter connections between them known as the default mode neural network) (Dunbar 2018;Kwak et al. 2018;Kiesow et al. 2020). (11) Several neuroimaging and comparative studies have shown that mentalising, self-control and other advanced cognitive capacities supported by these brain regions act as the intermediate bridge between brain size and group size (Powell et al. 2012;Dunbar 2018). ...
... In addition, (10) upwards of 20 neuroimaging studies of humans and three of monkeys have shown that the size of an individual's personal social network is highly correlated with the size of core elements in its neocortex (prefrontal cortex, temporo-parietal junction and temporal pole, plus the subcortical amygdala and cerebellum, and the massive white matter connections between them known as the default mode neural network) (Dunbar 2018;Kwak et al. 2018;Kiesow et al. 2020). (11) Several neuroimaging and comparative studies have shown that mentalising, self-control and other advanced cognitive capacities supported by these brain regions act as the intermediate bridge between brain size and group size (Powell et al. 2012;Dunbar 2018). (12) the brain's endorphin system plays a central role in creating the bonded relationships that underpin these networks in both primates and humans (and now, it seems, birds too!) (Pearce et al. 2017;Dunbar 2021). ...
... Social relationships vary in their levels of emotional closeness [14,22,36]: personal social networks typically consist of a handful of close and emotionally intense relationships (strong ties) and a larger num-ber of less close relationships (weak ties) (see, e.g. [12,46]). The strong ties at the center of the network are costly to maintain and therefore limited in number. ...
... Rather, there is a heterogeneous structure with a limited number of strong ties at the core of the network, surrounded by larger number of weaker ties. This pattern represents a tradeoff: while strong ties are crucial to our health and well-being [18,19,31], they demand significant time and emotional investment [11,12]. Weaker ties require less effort, but are nevertheless important, e.g., for access to new information and generally, for societal cohesion [14]. ...
... One could envision an underlying complete egocentric network with tie strengths that measure the closeness of all the relationship an ego maintain with their alters. Within this network there is a distribution of tie strengths where there are few strong and many weak ties [26]. Then observations on one channel of commu-nication would be incomplete samples of the underlying complete network (see, e.g., [16][17][18] for studies on network-level differences between calls and texts). ...
... Given the robustness of this finding, further research is now needed on the causes and consequences of individual variation in social signatures. Whilst everyone is subject to similar fundamental time and cognitive constraints on sociality [26], the way people choose to allocate their communication effort across their networks shows stable individual variation. Some of this individual variation appears to be due to personality characteristics [13], which are also broadly stable over time [29]. ...
The structure of egocentric networks reflects the way people balance their need for strong, emotionally intense relationships and a diversity of weaker ties. Egocentric network structure can be quantified with 'social signatures', which describe how people distribute their communication effort across the members (alters) of their personal networks. Social signatures based on call data have indicated that people mostly communicate with a few close alters; they also have persistent, distinct signatures. To examine if these results hold for other channels of communication, here we compare social signatures built from call and text message data, and develop a way of constructing mixed social signatures using both channels. We observe that all types of signatures display persistent individual differences that remain stable despite the turnover in individual alters. We also show that call, text, and mixed signatures resemble one another both at the population level and at the level of individuals. The consistency of social signatures across individuals for different channels of communication is surprising because the choice of channel appears to be alter-specific with no clear overall pattern, and ego networks constructed from calls and texts overlap only partially in terms of alters. These results demonstrate individuals vary in how they allocate their communication effort across their personal networks and this variation is persistent over time and across different channels of communication.
... For example, political disenchantment may be partially explained by an insidious erosion in trust concerning political actors (Hay, 2007) and more generally, people are living in what has been termed a 'risk society'/Risikogesellschaft (Beck, 1986;Giddens, 1990), in which there is a growing lack of trust in experts, and science more generally, to protect them from technological/environmental hazards. Trust is inextricably bound with the quality of human relations; it is recognized, for example, that trust is essential for maintaining and building social relationships and friendships and that breaches of trust place strains on, and can lead to breakdowns in, these relationships (Dunbar, 2018). Establishing trust has been shown to play an essential role in professional-client relations (Mikesell, 2013;Beach and Dozier, 2015;Frankel and Beckman, 2020;Chouliara et al., 2023), which may not only help to facilitate rapport and a safe caring environment, but may also create confidence in the information being presented to clients-see Fonagy and Allison (2014) on epistemic trust. ...
... As already noted, everyday conceptualizations of trust often stress its interpersonal or relational component (Dunbar, 2018), which has been shown to be especially important in medical consultations and psychotherapy sessions-for an overview of discursive studies on relationships, see Muntigl and Scarvaglieri (2023). There has been much research in patient-doctor communication, suggesting how a more caring, trusting relationship may be established and maintained. ...
Trust is argued to be essential in fostering cooperative communication, whereas a lack of trust is seen as detrimental to these aims. Over the years, there has been a slow but steady stream of research that has aimed to shed light on how trust is accomplished or broken down through discursive-interactional practices. In this mini review, we examine existing studies that take trust as a topic of investigation using micro-analytic, interactional methods, in order to provide readers with an up-to-date overview on new developments in this important field of research. From this review, we conclude that there exist two different, yet complementary, views on trust: Trust as an interactional principle and trust as a discursively accomplished phenomenon. We not only summarize important discursive work that provides a unique lens on how trust may be established and maintained through verbal and non-verbal resources, but also suggest some of the challenges interactional trust research still faces and some important areas for further investigation in which trust is a major concern.
... Demir et al. (2007)) identify categories such as 'friend,' 'best friend,' and 'close friend,' following Fehr's (1996) levels: stranger, acquaintance, friend, close friend, and best friend. Dunbar (2018) ordered relationships hierarchically from mere recognition to intimate bonds akin to those with a spouse. Friendship allegedly evolves from superficial to intimate levels through self-disclosure during repeated enjoyable interactions, a symmetrical, self-reinforcing, and reciprocal process. ...
... These levels, from transactional to personal, are guest, regular, casual friend, friend, close friend, and best friend. The levels mirror frameworks from previous friendship research (Fehr, 1996;Dunbar, 2018), which, however, lacked the level of 'casual friend'. This level parallels what Kurth (1970) describes as a "friendly relation". ...
This research explores commercial friendship within Dutch pubs, focusing on the transition from transactional to personal interactions between bartenders and guests. The study uses semi-structured interviews and thematic analysis to reveal that commercial friendship shares many similarities with non-commercial friendship but differs in important aspects. We found six levels of commercial friendship that range from minimal interactions, categorized as 'guest,' to deep, personal connections identified as 'best friend.' We identified three dimensions of commercial friendship quality: activities, self-disclosure, and social support. A critical finding is the 'tipping point'—a stage in the relationship development where interactions shift from professional to personal, characterized by mutual personal disclosure and balanced social support, redefining professional relationships. These findings demonstrate that commercial environments can foster genuine friendships, and provide valuable insights for enhancing interpersonal relationships within the hospitality industry.
... Indeed, some degree of competitiveness is often required to get to the top, whether in social or other competitive environments (e.g., university and workplaces). Such competition can help people gain access to valuable resources (e.g., food, status, and social support) which are, in turn, associated with improved physical and mental health, as well as better social and economic outcomes (Anderson et al., 2015;Dunbar, 2018;Holt-Lunstad et al., 2010). Specifically, competition plays an integral role for women, as gaining access to resources enhances their survival and reproductive fitness, with benefits that extend to the health and well-being of their children (Alami et al., 2020(Alami et al., , 2022. ...
Competition is a fundamental aspect of human behavior, but its social acceptability seems to be dependent on sex. While both men and women benefit from competition as a means of resource acquisition (Anderson et al., 2015; Durkee et al., 2020; Majolo et al., 2012; Zerjal et al., 2003), women tend to be socially penalized for their competitiveness in their friendships (Benenson & Schinazi, 2004; Goodwin, 1990; Maltz & Borker, 1982). We test between gender roles, social ecology, and target-specific accounts for which people, if anyone, disfavors competitive women as friends and friendly coworkers. In four U.S. experiments (N = 1,283; three preregistered) we find: Although women disfavor competitiveness in same-sex friends more than men, this effect is largely specific to competition directed toward oneself (and, secondarily, toward one’s friends); it attenuates when people consider friends’ competitiveness toward other targets (e.g., one’s rival), supporting a target-specific account. The findings imply that while people—especially women—do not universally disfavor competitive women, they selectively disapprove of competition when it poses a personal cost to themselves or their friends.
... Consequently, qualitative differences emerged between online and offline social networks [63]. This may be because, in the hierarchy of social relationships (the Dunbar circle [86,15]), the level of social relationships that an individual can make depends on the means of communication. Online communication via avatars in the virtual world may have forms similar to offline communication, such as online text communication. ...
Online communication via avatars provides a richer online social experience than text communication. This reinforces the importance of online social support. Online social support is effective for people who lack social resources because of the anonymity of online communities. We aimed to understand online social support via avatars and their social relationships to provide better social support to avatar users. Therefore, we administered a questionnaire to three avatar communication service users (Second Life, ZEPETO, and Pigg Party) and three text communication service users (Facebook, X, and Instagram) (N=8,947). There was no duplication of users for each service. By comparing avatar and text communication users, we examined the amount of online social support, stability of online relationships, and the relationships between online social support and offline social resources (e.g., offline social support). We observed that avatar communication service users received more online social support, had more stable relationships, and had fewer offline social resources than text communication service users. However, the positive association between online and offline social support for avatar communication users was more substantial than for text communication users. These findings highlight the significance of realistic online communication experiences through avatars, including nonverbal and real-time interactions with co-presence. The findings also highlighted avatar communication service users' problems in the physical world, such as the lack of offline social resources. This study suggests that enhancing online social support through avatars can address these issues. This could help resolve social resource problems, both online and offline in future metaverse societies.
... The benefits of making friends include providing social support, demonstrating proximity, protecting health, improving quality of life, providing emotional and psychological well-being, protecting the immune system, feeling selected, and reducing stress (Dunbar, 2018;Larivière-Bastien et al., 2022;Morgan, 2023). Letkiewicz et al. (2023) also stated that quality friendships significantly affect lifelong adjustment and psychological well-being. ...
This study investigated the effect of friendship ties education (FTE) on primary school students’ psychological well-being and peer relationships. We conducted the research using one of the quantitative research designs, the experimental design. The research study group consisted of 94 third-grade students enrolled in primary school who were divided into experimental, placebo, and control groups. This study was conducted with students in Istanbul in the spring semester of the 2021–2022 academic year. In the study, we applied FTE to the experimental group, applied cooperative learning (CL) to the placebo group, and did not apply any educational activity to the control group. We gathered the research data using a scale of psychological well-being and peer relationships. We analyzed the data obtained through the scales with the t-test and ANOVA included in the SPSS package program. According to the findings, the experimental group’s psychological well-being and peer relations scores were significantly higher than those of the control and placebo groups following activities. In addition, the placebo group students scored considerably higher than the control group regarding psychological well-being and peer relationships. The findings demonstrate the significance of FTE and CL for developing psychological well-being and peer relationships.
... [17,31] for details). In this sense, a complete understanding of higher-order interactions in social interaction networks has become a compulsory assignment [32][33][34]. ...
Modeling social systems as networks based on pairwise interactions between individuals offers valuable insights into the mechanisms underlying their dynamics. However, the majority of social interactions occur within groups of individuals, characterized by higher-order structures. The mechanisms driving group formation and the impact of higher-order interactions, which arise from group dynamics, on information spreading in face-to-face interaction networks remain insufficiently understood. In this study, we examine some representative human face-to-face interaction data and find the recurrent patterns of groups. Moreover, we extend the force-directed motion (FDM) model with the forces derived from similarity distances within a hidden space to reproduce the recurrent group patterns and many key properties of face-to-face interaction networks. Furthermore, we demonstrate that the FDM model effectively predicts information-spreading behaviors under higher-order interactions. Finally, our results reveal that the recurrence of triangular groups inhibits the spread of information in face-to-face interaction networks, and the higher-order interactions will make this phenomenon more pronounced. These findings represent a significant advancement in the understanding of group formation and may open new avenues for research into the effects of group interactions on information propagation processes.
... Furthermore, women who have <3 friends whom they feel at ease talking about private matters were lonely. The way to maintain the emotional closeness of friendships may differ by gender, with women needing to make an effort to spend more time talking together and men needing to increase doing more activities together (Dunbar, 2018;Roberts & Dunbar, 2015). Fiori et al. reported that the receipt of emotional support was associated with mental health in women only (Fiori & Denckla, 2012). ...
Aim
Loneliness among older people is prevalent. Few studies have examined the association of loneliness with the type of friendship and number of friends. This study aimed to clarify the loneliness‐related factors among older adults by gender focusing on the type of friendship and number of friends.
Methods
An anonymous, self‐administered questionnaire survey was conducted on 1610 older adults in Japan. The questionnaire included basic characteristics, health status used by the self‐administered dementia checklist, type of friendship and number of friends evaluated by the Lubben Social Network Scale, and loneliness evaluated using the University of California, Los Angeles Loneliness Scale. Univariate analysis was performed with loneliness as the dependent variable, and multiple logistic regression analysis was also performed.
Results
A total of 1082 older adults were included for analysis. The loneliness rate was 16.8%. Regarding the type of friendship and number of friends, having <3 close friends to call on for help (tangible aid) was most associated with loneliness (men odds ratio [OR]: 2.88, women OR: 3.10). Higher awareness of the participants of subjective symptoms of dementia was proportionally related to loneliness (men, OR: 3.06; women, OR: 2.40). Among women, economic insecurity (OR: 1.68), subjective health (OR: 2.12), having <3 friends with whom they feel easy to talk about private matters (emotional support) were related to loneliness (OR: 2.38).
Conclusion
The results suggested that the type of friendship and number of friends, economic insecurity, and health status might be associated with loneliness among older adults. Several factors related to loneliness might differ by gender.
... These findings are consistent with previous studies reporting the role of ADM in organizing neuroendocrine responses to stress, including simulating the SNS and HPA axis 57 , as well as regulating stress hormones 58 . Brain-derived ADM has the potential to control oxytocin release 59 , which is a crucial social peptide 60 . Additionally, variant ASGR1 was associated with low cholesterol and a reduced risk of CVD 61,62 . ...
The biology underlying the connection between social relationships and health is largely unknown. Here, leveraging data from 42,062 participants across 2,920 plasma proteins in the UK Biobank, we characterized the proteomic signatures of social isolation and loneliness through proteome-wide association study and protein co-expression network analysis. Proteins linked to these constructs were implicated in inflammation, antiviral responses and complement systems. More than half of these proteins were prospectively linked to cardiovascular disease, type 2 diabetes, stroke and mortality during a 14 year follow-up. Moreover, Mendelian randomization (MR) analysis suggested causal relationships from loneliness to five proteins, with two proteins (ADM and ASGR1) further supported by colocalization. These MR-identified proteins (GFRA1, ADM, FABP4, TNFRSF10A and ASGR1) exhibited broad associations with other blood biomarkers, as well as volumes in brain regions involved in interoception and emotional and social processes. Finally, the MR-identified proteins partly mediated the relationship between loneliness and cardiovascular diseases, stroke and mortality. The exploration of the peripheral physiology through which social relationships influence morbidity and mortality is timely and has potential implications for public health.
... The increased frequency of social behaviour in the shell bed 216 population (B) may be a response to a more active local conspecific environment, with frequent engagement with neighbours who are encountered more often due to their higher density. Maintaining 218 social relationships with many neighbours is thought to be energetically and cognitively costly (Dunbar, 2018) and we found that the shell bed population, which had a four-fold higher interaction rate than the 220 sand and shell population, had concomitantly larger brains. Such a finding was only possible through the use of direct behavioural observation of wild animals in combination with measurements of neuroanatomy. ...
The Social Brain Hypothesis (SBH) proposes that complex social environments drive the evolution of larger brains and specific neuroanatomical adaptations. This relationship can be difficult to study in the wild, because species that differ in social organization may also diverge in morphology, ecology, phylogeny, and other life history parameters. Here we use two populations of the shell-dwelling cichlid Neolamprologus brevis with contrasting social environments to test whether increased social complexity is associated with larger brain sizes or specific regional adaptations. Behavioral observations revealed similarly low feeding rates in both populations, but significantly more frequent social interaction frequencies in the population one of the populations. This population had larger total brain volumes relative to body size, with a disproportionately larger telencephalon and a smaller hypothalamus, suggesting region-specific adaptations to social demands. By integrating behavioral quantification and neuroanatomical analysis, our study highlights the importance of sociality as a driver of brain evolution and demonstrates the utility of cichlid fish as a model for testing the SBH in non-mammalian systems. These findings provide empirical support for the SBH and underscore the value of combining behavioral and morphological data in evolutionary neuroethology.
... The school leaders recognised a mutual and reciprocal relationship of trust and obligation, shared with a willingness to act prosocially (Dunbar, 2018). Trust was viewed as central because it underpinned everything from how they interacted with each other (I trust that you will not betray me) to their willingness to offer help (I trust that you will help me out one day) to trading (I trust that you are giving me high quality graduates). ...
Set within the broader employment crisis facing Australian schools, attracting preservice teachers to teach in a regional, rural, and remote (RRR) school community has been a long-standing educational priority. Research has identified the role of placement initiatives, the benefits of preparing preservice teachers for RRR contexts, and the centrality and significance of community and relationships. What is less frequently acknowledged is the role of school leaders in acting as the nexus between preservice teachers and the RRR community. Specifically, how leaders effectively support and enact relationship-based initiatives for preservice teachers. This research explores the leadership strategies of a group of high school leaders—leaders from a large metropolitan Prep-Year 12 College (Brisbane, Queensland) and Far North Queensland. Central to the leadership partnerships is a preservice teacher RRR preparation program facilitated by a Brisbane College via their Teacher Enhancement Centre. In this paper, we report on the strengths of their program in establishing key connections. Implications are drawn in relation to how school leaders connect with other leaders, and preservice teachers through the program, and how these connections can support place-based experiences for preservice teachers while concurrently addressing the staffing needs of RRR schools.
... Same game, except larger scale and faster deployment. Social media thus have a profound impact on collective cohesion, group interactions but also individual cognitive functions and this is vastly documented namely through the number of data obtained from harnessing social media (Dunbar, 2018;Firth et al., 2019). ...
The use of tech in mental health has drastically increased in the recent years. Indeed advances in technology have made it possible to better characterize, predict, prevent, and treat a range of psychiatric illnesses. What is less paid attention to however is the impact of tech on our mental health and brain functioning, or what we have called, the digitalization of our brains. The acceleration of tech is correlated with an increased prevalence of reported mental health disorders. The overuse of technology and social media is also correlated to cognitive and affective alterations in apparently healthy individuals, including increased feelings of isolation, stress, memory and attention deficits, as well as modifications in information and reward processing. In this review we discuss the impact of technology on our mental health and brains, emphasizing on the need to take into account our brain capacities in order to optimize the integration of tech in our daily lives all while preserving our core cognitive functions.
... In summary, research suggests that the social categorization of individuals into ingroups and outgroups influences how we perceive and interpret information about them and their actions (Hastorf and Cantril, 1954;Gutsell and Inzlicht, 2010;Molenberghs et al., 2012;Molenberghs, 2013;Dunbar, 2018). For instance, Hastorf and Cantril (1954) asked rival football fans to watch a contentious game and assess which team engaged in more aggressive play. ...
Research suggests that individuals consistently demonstrate favorable attitudes towards members of their ingroups compared to those belonging to other social groups. Such ingroup biases are observed not only in well-established historical groups but also in minimal group settings. The current study investigates the robustness of the said ingroup bias across different contexts through four experiments. In Experiment 1, participants were merely assigned to one of the two existing minimal groups, and their ingroup bias was assessed. In the next three experiments (Exps 2a - 2c), the participants were assigned to one of the two minimal groups, and the relationship between the groups was manipulated. In Experiment 2a, both groups were described as good and in a mutually harmonious relationship; in Experiment 2b, the two groups were in a conflicted relationship, with the ingroup described as good and the outgroup as bad; and finally, in Experiment 2c, both groups were again in a conflicted relationship with the ingroup being described as bad and the outgroup as good. The degree of ingroup bias was indexed in terms of faster response times, higher accuracy, and greater sensitivity on a perceptual-matching task. Interestingly, while the preliminary analysis showed a significant moderation of bias measures across the four experiments, a more detailed examination using Bayesian regression analysis and Drift-Diffusion Modeling established a strong persistence of ingroup favoritism despite changing group characteristics and relations. Indeed, the changing relations didn’t affect the robust ingroup bias much as the general trend for favoring one’s own group persisted across all experiments. The minimal yet robust nature of ingroup favoritism is explicated.
... This activity is related to one aspect of social-emotional competence which is social awareness, characterized by the ability to empathize with other people, respect individuals and other groups, and recognize similarities and differences (Dewi, 2016;Hadi, 2011). Through this, teenagers understand that each person has a basic need to be part of a social group (Dunbar, 2018) by showing this can increase a person's identification with the group. ...
Background: Social-emotional competence have a high level of urgency to be actualized especially in middle school students because through this competency it is able to prevent the level of delinquency and crime and is able to improve academic achievement in students. This study aimed to determine the effectiveness of friendship management training with prosocial orientation to improve the social-emotional competence of middle school students. Methods: This study used an experimental method with a pretest-posttest control group design. A total of 39 middle school students in Padang City, Indonesia, were selected by a randomization technique to be assigned to a control or experimental group after completing an informed consent. Social-emotional competence was measured using the Social and Emotional Competencies Evaluation Questionnaire (Coelho et al., 2015) developed by researchers. The scale had an Alpha Cronbach of 0.935, indicating high reliability. Results: Result showed that the ANOVA test results showed that friendship management training effectively improved the social-emotional competence of middle school students (F = 6.633; p < 0.05). The effect of treatment was proven to be significant, indicating an increase in the social-emotional competence of students who received prosocial-oriented friendship management training. The average increase in social-emotional competence of students with friendship management training was higher than that of the control group (F = 2,302; p > 0,05). Conclusions: According the results, friendship management training was found to be effective in increasing social-emotional competence of middle school students. Therefore, the training is recommended as a promising program to be implemented in schools to promote social-emotional competence of students.
... The layers emerge owing to both the frequency with which individuals contact each other [4,5] and the sense of trust they have through increasing familiarity [6]. The evaluation of cues for community membership, known as the Seven Pillars of Friendship [7], and the exchange of tokens have previously postulated this [8,9]. The base of the group hierarchy lies at approximately five individuals. ...
Human communities have self-organizing properties in which specific Dunbar Numbers may be invoked to explain group attachments. By analysing Wikipedia editing histories across a wide range of subject pages, we show that there is an emergent coherence in the size of transient groups formed to edit the content of subject texts, with two peaks averaging at around N=8 for the size corresponding to maximal contention, and at around N=4 as a regular team. These values are consistent with the observed sizes of conversational groups, as well as the hierarchical structuring of Dunbar graphs. We use a model of bipartite trust to derive a scaling law that fits the data and may apply to all group size distributions when these are based on attraction to a seeded group process. In addition to providing further evidence that even spontaneous communities of strangers are self-organizing, the results have important implications for the governance of the Wikipedia commons and for the security of all online social platforms and associations.
... Here, we found structural asymmetry change to largely tie into markers of mental health, cognitive abilities, and environmental factors. One's relationship with one's inner social circle is amongst the most important social interaction for one's psychological and physical well-being (Dunbar, 2018;Schurz et al., 2021). Time since last contact is strongly tied to emotional closeness, particularly for kin relationships (Roberts & Dunbar, 2011). ...
Human beings may have evolved the largest asymmetries of brain organization in the animal kingdom. Hemispheric left-vs-right specialization is especially pronounced in our species-unique capacities. Yet, brain asymmetry features appear to be strongly shaped by non-genetic influences. We hence charted the largest longitudinal brain-imaging adult resource, yielding evidence that brain asymmetry changes continuously in a manner suggestive of neural plasticity. In the UK Biobank population cohort, we demonstrate that asymmetry changes show robust associations across 959 distinct phenotypic variables spanning 11 categories. We also find that changes in brain asymmetry over years co-occur with changes among specific lifestyle markers. Finally, we reveal relevance of brain asymmetry changes to major disease categories across thousands of medical diagnoses. Our results challenge the tacit assumption that asymmetrical neural systems are highly conserved throughout adulthood.
... Prior research has found that opportunities for ERI exploration can depend on the availability of major socializing contexts such as peers and schools (Douglass et al., 2017;Rivas-Drake et al., 2017). In particular, the ethnic/racial composition of one's friendships (relationships selected from available peers that involve an emotional bond over time; Dunbar, 2018), has been shown to play a significant role in how adolescents make sense of their own identities . However, the current literature on how multiple levels of socializing contexts (schools, friends) jointly shape ERI over time remains limited (Douglass et al., 2017;Rivas-Drake et al., 2014). ...
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.
... Even if overlooked in current phenomenological research on interpersonal understanding, the basic idea is not new. The view that close personal relationships tend to constitute a core layer of an individual's social world finds support in social psychology (Baumeister and Leary 1995), cognitive and evolutionary psychology (Dunbar 2018), and moral philosophy (e.g., Broad 1942, pp. 55-56;Lange 2022), where it has been discussed in connection with the "puzzle of partiality," i.e. how to reconcile the preferential treatments of intimates with the impartial demands of morality (Keller 2013). ...
Current research on second-person relations has often overlooked that this is not a new topic. Addressed mostly under the heading of the “I–thou relation,” second-person relations were discussed by central figures of the phenomenological tradition, including Edmund Husserl and Martin Heidegger, but also quite extensively by much lesser-known authors, such as Karl Löwith, Ludwig Binswanger, and Semyon L. Frank, whose work has been undeservedly neglected in current research. This paper starts off by arguing that, in spite of the rightly acknowledged differences between the Husserlian and the Heideggerian approaches to the investigation of the social world, both approaches converge in the claim that the I–thou relation is founded on more basic forms of sociality. In a second step, against the background of Frank’s and Binswanger’s challenges to that claim, I argue that Löwith’s proposal that the I–thou relation is a primordial form of sociality can be vindicated by conceptualizing I–thou relations as close personal relationships (paradigmatically exemplified by companion friendships and romantic partnerships). After assessing how Löwith’s approach to the I–thou relation stands vis-à-vis Heidegger’s and Husserl’s views, I conclude by suggesting how Löwith’s approach can contribute to current research on second-person relations.
... Recent research hinted that there would be a very low chance of learning opportunities for subordinates associated with lower organizational commitment and a higher risk of turnover [22]. This entitles the need to examine how trust can be maintained while interacting online [23]. Ref. [24] extensively studied remote leadership and was able to identify similar concerns shared between employees and their leaders. ...
Remote work as a new working pattern is considered of high importance in determining the competitiveness of the institutions that adopt this form of work. This trend toward remote working has benefited workers greatly in terms of flexibility and work-life balance and has had unanticipatedly positive effects on sustainability. The issue has grown in importance considering recent development of digitalization and high concern of countries to achieve the sustainable goals. This study attempts to examine the effect of three explanatory variables: remote work, institutional efficiency, and work management on the competitiveness of finance institutions in Saudi Arabia. To collect the primary data, a survey was conducted on a stratified random sample that comprised 1270 respondents. The sample covers the three finance sector segments: banks, insurance, and finance companies. Correlation analyses, one-sample t-tests, and multi-regression analyses are applied to analyze the data. The results of the study showed that there is a positive significant relationship between the three explanatory variables of the study and institutional competitiveness. Besides, the regression model revealed that the two explanatory variables; remote work and institution efficiency are statistically significant at 95% confidence intervals, while work management is not statistically significant. The study recommends promoting remote work to increase the finance institution's competitiveness by restructuring the work policies, designing work strategies, and introducing a new management system compatible with remote work.
... Ultimately, friendships contribute to human happiness as they can fulfil several psychological needs (Demir & Özdemir, 2010). Yet, friends demand limited resources like time, cognitive capacity, and preferential treatment (Barakzai & Shaw, 2018;Dunbar, 2018;Powell et al., 2012), thereby constraining the size of friendship networks (Hill & Dunbar, 2003). Given these upper limits on the quantity of friends in whom individuals can invest, humans should carefully select their friends in a process attuned to maximize their own fitness and goals (Krems & Conroy-Beam, 2020). ...
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.
Enduring loneliness has serious physical and mental health implications. Patients with mental health problems are at risk of experiencing problems related to loneliness. Therefore, it is important to increase knowledge about how loneliness is experienced and managed in this particular group. The aim of the study was to explore (1) psychiatric patients' experiences of different forms of loneliness, (2) associated problems, including difficulties with prosocial signaling, and (3) strategies used to combat loneliness, to better understand how loneliness affects psychiatric patients and how patients manage their loneliness. A total of 110 psychiatric patients were recruited at eight outpatient clinics in Region Stockholm for a larger study of loneliness. The first fifteen patients who also agreed to participate in the present substudy were invited to meet a trainee psychologist who conducted a semi-structured interview. A reflexive thematic analysis with a codebook approach was used to analyze the transcripts. The described experiences of loneliness were primarily examples of social and emotional loneliness with one prominent theme: "Hopelessly lonely". Associated problems were summarized in two themes: "The inevitable road to loneliness" and "Social signals are confusing and push others away". Regarding patients' strategies for combating loneliness, one theme emerged: "Using strategies that focus on the current moment". The results also included a total of sixteen subthemes. Loneliness was described as something painful that is inevitable and unchangeable, with a self-reinforcing loneliness loop leading to social and emotional loneliness, and as something that is intertwined with mental health problems. These results are in accordance with research. In addition, patients described a variety of prosocial signaling deficits and feelings of being disconnected from others. They also reported using strategies that primarily alleviated their immediate suffering when they were alone, rather than focusing on approaches with long-term effects on reducing loneliness, such as participating in social activities combined with effective social signaling. Future research should investigate whether increased awareness of social signaling, as well as social activities combined with improved prosocial signaling and strengthened self-belief, would constitute effective steps for patients to combat enduring loneliness. It also seems important to help patients reduce hopelessness related to loneliness.
Myths about a remote shared past can certainly promote cooperation between distantly related people, seemingly via their impact on our social cognition, and ultimately facilitate the achievement of complex tasks in large-scale societies. Nonetheless, the creation and transmission of these complex narratives are not possible without the parallel development of sophisticated language(s), endowed with properties like displacement (enabling mental travels in space and time) and complex syntax (enabling the assembly and communication of complex thoughts).
Representing social systems as networks, starting from the interactions between individuals, sheds light on the mechanisms governing their dynamics. However, networks encode only pairwise interactions, while most social interactions occur among groups of individuals, requiring higher-order network representations. Despite the recent interest in higher-order networks, little is known about the mechanisms that govern the formation and evolution of groups, and how people move between groups. Here, we leverage empirical data on social interactions among children and university students to study their temporal dynamics at both individual and group levels, characterising how individuals navigate groups and how groups form and disaggregate. We find robust patterns across contexts and propose a dynamical model that closely reproduces empirical observations. These results represent a further step in understanding social systems, and open up research directions to study the impact of group dynamics on dynamical processes that evolve on top of them.
The Internet of Things (IoT) necessitates secure communication and high availability among objects at the network edge to ensure reliable object-to-object transactions. In the IoT networks, despite resource limitations, especially at the edge of the network, the potential for error is high. Therefore, a mechanism to increase the reliability, lifetime, and stability of the network is necessary. In this paper, we introduce a trust evaluation framework based on a reliability-based friendly relationship method in IoT networks. We present a conceptual trust model that captures the overall performance of the IoT social network based on parameters such as nodes’ communication history experiences. Trust in the IoT network is built upon a harmonious communication environment that aligns with the trustworthiness of each object and its ability to maintain continuous interactions. We propose an empirical Trust Indicator (TI) that captures individual agents’ experiences in IoT groups, considering the results of system executions, current experience values, and timestamps of interactions. Mathematical models are developed to analyze the dynamics of trust, including trust increase through increased reliability and collaborative interactions and trust decay due to non-cooperative interactions and lack of communication. The model parameters in IoT groups through simulation show that in this system based on the level of reliability and its increase or decrease, its direct effect can be evaluated by quantitative measurement of mean time to failure (MTTF), which is a measure of devices trust and the network itself.
Hlavným cieľom výskumu bolo analyzovať vzťah medzi používaním sociálnych médií a wellbeingom detí a mládeže. Zisťovali či existuje vzťah medzi angažovanosťou na sociálnych médiách a sociálno-emocionálnym well-beingom. Na získanie údajov boli použité nástroje: škála angažovanosti v oblasti sociálnych médií (SMEQ) vytvorená za účelom merania rozsahu zapájania sociálnych médií do kľúčových každodenných aktivít jedincov, dotazník Global Kids Online questionaire zameraný na zistenie skúseností detí a mládeže s internetom a digitálnymi technológiami v každodennom živote a škála na meranie sociálno-emocionálneho well-beingu (SEWB) zameraná na meranie atribútov sociálno-emocionálneho well-beingu. Výskumný súbor tvorilo 699 respondentov z toho bolo 344 mužov a 355 žien s priemerným vekom 13 rokov. Výsledky výskumu preukázali že angažovanosť žiakov na sociálnych médiách nevplýva na ich sociálno-emocionálny well-being.
The man has created a social being, and therefore one of the most basic human needs is his need to escape from solitary confinement. The institution of "friendship" as the spiritual connection of individuals and the basis of their material relations is one of the best ways to satisfy this need and therefore the inherently desirable of man.On the other hand, the central idea of the social capital theory is "social relations". Therefore, it can be concluded that the relationship of "friendship" as a special type of "social relations" between human beings is one of the main factors in promoting the social capital of society. The the present study, first relying on Shiite sources and using the qualitative method of "grounded theory", seeks to present an Islamic theory of friendship and making friends. And then, with rational-logical analysis, the the present study has examined the implications of that theory, which it calls "transcendent friendship," in increasing the positive (constructive) social capital of society.
Remote work as a new working pattern is considered of high importance in determining the competitiveness of the institutions that adopt this form of work. This study attempts to examine the effect of three explanatory variables: remote work, institutional efficiency, and work management on the competitiveness of finance institutions in Saudi Arabia. To collect the primary data, a survey is conducted on a stratified random sample that comprised 1270 respondents. The sample covers the three finance sector segments: banks, insurance, and finance companies. Correlation analyses, one-sample t-tests, and multi-regression analyses are applied to analyze the data. The results of the study showed that there is a positive significant relationship between the three explanatory variables of the study and institutional competitiveness. Besides, the regression model revealed that the two explanatory variables; remote work and institution efficiency are statistically significant at 95% confidence intervals, while work management is not statistically significant. The study recommends promoting remote work to increase the finance institution’s competitiveness by restructuring the work policies, designing work strategies, and introducing a new management system compatible with remote work.
В статье рассмотрены территориальные связи тувинцев-тоджинцев Тоджинского кожууна Республики Тыва, сойотов Окинского района Республики Бурятия, тофаларов Нижнеудинского района Иркутской области, эвенков Тындинского района Амурской области и Нерюнгринского района Республики Саха (Якутия). Это территории традиционного проживания коренных малочисленных народов из разных субъектов Российской Федерации, представляющие собой отдаленные и труднодоступные территории. Исследование направлено на поиск оптимального набора показателей устойчивого развития на локальном уровне для территорий с проживанием коренных народов, сохраняющих традиционные формы природопользования. Авторы считают, что определение таких показателей можно осуществить через применение метадисциплинарной сетевой концепции с онтологиями, моделями и индикаторами, которые показывают согласованность хозяйственной деятельности, экологического равновесия, этнокультурного и социального комфорта. Выявлены типы социальных связей, присутствующие в трех блоках топологического поля: семейные (родственные) отношения, культурное взаимодействие, хозяйственная деятельность и традиционное жизнеобеспечение. Основные выводы авторы видят в стратификации и детализации связей жителей территорий по типу и масштабам взаимодействия.
Relationships with parents and friends may work together to increase the risk of adjustment problems in emerging adulthood. However, it is still undetermined if social relationships act in an additive (i.e., serve as unique predictors) or moderating (i.e., interact with other predictors) fashion. In a cross-sectional sample of 859 female college students ( M age = 19.53, SD = 1.49; 73.9% White) from a large university in the south-central United States, we assessed how parents and best friends impact emerging adult internalizing symptoms, risky behavior, and health problems. We found that low levels of best friend risky behavior attenuated the links between father-emerging adult relationship quality and risky behavior and internalizing symptoms, and high levels of father-emerging adult relationship quality magnified the association between mother-emerging adult relations and internalizing symptoms. Ultimately, these results indicate that relationships with parents and friends served as additive or unique predictors of emerging adult health and behavior.
Background: Students often form project teams by themselves rather than impose pre-defined teams because it leads to better study outcomes. However, few scholars have investigated the mechanisms driving the formation of self-organized groups.
Aims: We examine three underlying and interrelated antecedents of project team formation: friendships, familiarity with fellow team members due to prior co-working experiences, and similarity of team members regarding gender, academic achievement, and preferred collaborators.
Sample: The data encompasses 70 first-year university students asked to self-form teams to carry out a semester project.
Methods: We utilize Exponential Random Partition Models. This new method allows us to model how friendships, familiarity, and similarity affect self-organized group compositions while accounting for each factor's relative importance.
Results: The results show that friends are more likely to end up in the same team than non-friends. Similarity is also an important antecedent for team formation: Students with the same gender and similar grades are more likely to end up in the same team. Familiarity and preferred collaboration showed negligible effects.
Conclusions: Our findings emphasize that educators must consider academic and non-academic factors when allowing students to self-organize in teams, depending on what goal educators strive to achieve with team projects.
We examine community longevity as a function of group size in three historical, small scale agricultural samples. Community sizes of 50, 150 and 500 are disproportionately more common than other sizes; they also have greater longevity. These values mirror the natural layerings in hunter-gatherer societies and contemporary personal networks. In addition, a religious ideology seems to play an important role in allowing larger communities to maintain greater cohesion for longer than a strictly secular ideology does. The differences in optimal community size may reflect the demands of different ecologies, economies and social contexts, but, as yet, we have no explanation as to why these numbers seem to function socially so much more effectively than other values.
The question as to why primates have evolved unusually large brains has received much attention, with many alternative proposals all supported by evidence. We review the main hypotheses, the assumptions they make and the evidence for and against them. Taking as our starting point the fact that every hypothesis has sound empirical evidence to support it, we argue that the hypotheses are best interpreted in terms of a framework of evolutionary causes (selection factors), consequences (evolutionary windows of opportunity) and constraints (usually physiological limitations requiring resolution if large brains are to evolve). Explanations for brain evolution in birds and mammals generally, and primates in particular, have to be seen against the backdrop of the challenges involved with the evolution of coordinated, cohesive, bonded social groups that require novel social behaviours for their resolution, together with the specialized cognition and neural substrates that underpin this. A crucial, but frequently overlooked, issue is that fact that the evolution of large brains required energetic, physiological and time budget constraints to be overcome. In some cases, this was reflected in the evolution of ‘smart foraging’ and technical intelligence, but in many cases required the evolution of behavioural competences (such as coalition formation) that required novel cognitive skills. These may all have been supported by a domain-general form of cognition that can be used in many different contexts.
This article is part of the themed issue ‘Physiological determinants of social behaviour in animals’.
Kinship and friendship are key human relationships. Increasingly, data suggest that people are not less altruistic toward friends than close kin. Some accounts suggest that psychologically we do not distinguish between them; countering this is evidence that kinship provides a unique explanatory factor. Using the Implicit Association Test, we examined how people implicitly think about close friends versus close kin in three contexts. In Experiment 1, we examined generic attitudinal dispositions toward friends and family. In Experiment 2, attitude similarity as a marker of family and friends was examined, and in Experiments 3 and 4, strength of in-group membership for family and friends was examined. Findings show that differences exist in implicit cognitive associations toward family and friends. There is some evidence that people hold more positive general dispositions toward friends, associate attitude similarity more with friends, consider family as more representative of the in-group than friends, but see friends as more in-group than distant kin.
In this paper, we examine the role of lies in human social relations by implementing some salient characteristics of deceptive interactions into an opinion formation model, so as to describe the dynamical behaviour of a social network more realistically. In this model, we take into account such basic properties of social networks as the dynamics of the intensity of interactions, the influence of public opinion and the fact that in every human interaction it might be convenient to deceive or withhold information depending on the instantaneous situation of each individual in the network. We find that lies shape the topology of social networks, especially the formation of tightly linked, small communities with loose connections between them. We also find that agents with a larger proportion of deceptive interactions are the ones that connect communities of different opinion, and, in this sense, they have substantial centrality in the network. We then discuss the consequences of these results for the social behaviour of humans and predict the changes that could arise due to a varying tolerance for lies in society.
Two decades of research suggest social relationships have a common evolutionary basis in humans and other gregarious mammals. Critical to the support of this idea is growing evidence that mortality is influenced by social integration, but when these effects emerge and how long they last is mostly unknown. Here, we report in adult female macaques that the impact of number of close adult female relatives, a proxy for social integration, on survival is not experienced uniformly across the life course; prime-aged females with a greater number of relatives had better survival outcomes compared with prime-aged females with fewer relatives, whereas no such effect was found in older females. Group size and dominance rank did not influence this result. Older females were less frequent targets of aggression, suggesting enhanced experience navigating the social landscape may obviate the need for social relationships in old age. Only one study of humans has found age-based dependency in the association between social integration and survival. Using the largest dataset for any non-human animal to date, our study extends support for the idea that sociality promotes survival and suggests strategies employed across the life course change along with experience of the social world. © 2017 The Author(s) Published by the Royal Society. All rights reserved.
The social brain hypothesis posits that social complexity is the primary driver of primate cognitive complexity, and that social pressures ultimately led to the evolution of the large human brain. Although this idea has been supported by studies indicating positive relationships between relative brain and/or neocortex size and group size, reported effects of different social and mating systems are highly conflicting. Here, we use a much larger sample of primates, more recent phylogenies, and updated statistical techniques, to show that brain size is predicted by diet, rather than multiple measures of sociality, after controlling for body size and phylogeny. Specifically, frugivores exhibit larger brains than folivores. Our results call into question the current emphasis on social rather than ecological explanations for the evolution of large brains in primates and evoke a range of ecological and developmental hypotheses centred on frugivory, including spatial information storage, extractive foraging and overcoming metabolic constraints.
A central assumption that underpins much of the discussion of the role played by social cognition in brain evolution is that social cognition is unusually cognitively demanding. This assumption has never been tested. Here, we use a task in which participants read stories and then answered questions about the stories in a behavioural experiment (39 participants) and an fMRI experiment (17 participants) to show that mentalising requires more time for responses than factual memory of a matched complexity and also that higher orders of mentalising is disproportionately more demanding and requires the recruitment of more neurons in brain regions known to be associated with theory of mind, including insula, posterior STS, temporal pole, and cerebellum. These results have significant implications both for models of brain function and for models of brain evolution.
Both small-scale human societies and personal social networks have a characteristic hierarchical structure with successively inclusive layers of 15, 50, 150, 500, and 1,500 individuals. It has been suggested that these values represent a set of natural social attractors, or “sweet spots,” in organizational terms. We exploited the new phenomenon of permanent (i.e., residential) campsites to ask whether these values are present in the size distribution of the numbers of residents in these naturally small-scale communities. In two separate data sets of different grain, we find consistent evidence for sites with 50, 150, 500, and maybe 1,500 residents. We infer that these reflect numerical sizes at which communities may in some way be socially optimal. Our data do not allow us to say why this pattern emerges, but the consistency of the results and the fact that the predetermined sizes of permanent campsites adhere to this pattern suggest that it may arise from the limits on the number of relationships that make an effective community. © 2017 by The Wenner-Gren Foundation for Anthropological Research. All rights reserved.
Alcohol use has a long and ubiquitous history. Despite considerable research on the misuse of alcohol, no one has ever asked why it might have become universally adopted, although the conventional view assumes that its only benefit is hedonic. In contrast, we suggest that alcohol consumption was adopted because it has social benefits that relate both to health and social bonding. We combine data from a national survey with data from more detailed behavioural and observational studies to show that social drinkers have more friends on whom they can depend for emotional and other support, and feel more engaged with, and trusting of, their local community. Alcohol is known to trigger the endorphin system, and the social consumption of alcohol may thus have the same effect as the many other social activities such as laughter, singing and dancing that we use as a means of servicing and reinforcing social bonds.
Fiction, whether in the form of storytelling or plays, has a particular attraction for us: we repeatedly return to it and are willing to invest money and time in doing so. Why this is so is an evolutionary enigma that has been surprisingly underexplored. We hypothesize that emotionally arousing drama, in particular, triggers the same neurobiological mechanism (the endorphin system, reflected in increased pain thresholds) that underpins anthropoid primate and human social bonding. We show that, compared to subjects who watch an emotionally neutral film, subjects who watch an emotionally arousing film have increased pain thresholds and an increased sense of group bonding.
Social networks require active relationship maintenance if they are to be kept at a constant level of emotional closeness. For primates, including humans, failure to interact leads inexorably to a decline in relationship quality, and a consequent loss of the benefits that derive from individual relationships. As a result, many social species compensate for weakened relationships by investing more heavily in them. Here we study how humans behave in similar situations, using data from mobile call detail records from a European country. For the less frequent contacts between pairs of communicating individuals we observe a logarithmic dependence of the duration of the succeeding call on the time gap with the previous call. We find that such behaviour is likely when the individuals in these dyadic pairs have the same gender and are in the same age bracket as well as being geographically distant. Our results indicate that these pairs deliberately invest more time in communication so as to reinforce their social bonding and prevent their relationships decaying when these are threatened by lack of interaction.
Electronic supplementary material:
The online version of this article (doi:10.1140/epjds/s13688-016-0097-x) contains supplementary material.
Although simple social structures are more common in animal societies, some taxa (mainly mammals) have complex, multi-level social systems, in which the levels reflect differential association. We develop a simulation model to explore the conditions under which multi-level social systems of this kind evolve. Our model focuses on the evolutionary trade-offs between foraging and social interaction, and explores the impact of alternative strategies for distributing social interaction, with fitness criteria for wellbeing, alliance formation, risk, stress and access to food resources that reward social strategies differentially. The results suggest that multi-level social structures characterised by a few strong relationships, more medium ties and large numbers of weak ties emerge only in a small part of the overall fitness landscape, namely where there are significant fitness benefits from wellbeing and alliance formation and there are high levels of social interaction. In contrast, 'favour-the-few' strategies are more competitive under a wide range of fitness conditions, including those producing homogeneous, single-level societies of the kind found in many birds and mammals. The simulations suggest that the development of complex, multi-level social structures of the kind found in many primates (including humans) depends on a capacity for high investment in social time, preferential social interaction strategies, high mortality risk and/or differential reproduction. These conditions are characteristic of only a few mammalian taxa.
Studying the evolution of cooperative breeding and group living requires simultaneous quantification of both helping benefits and competitive costs within groups. Although such research has traditionally focused on the fitness benefits of helping behavior, increasing evidence now highlights reproductive competition in cooperatively breeding animals including humans. Human groups consist of cooperative individuals of varying relatedness, predicted to lead to conflict when resources are limited and relatedness low. However, few studies exist that determine the costs of co-breeding to both parties sharing resources. Here, we studied female reproductive competition in historical Finnish joint-families where brothers stayed on their natal farms and sisters married out, so that several unrelated women of reproductive age co-resided in the same households. Using detailed parish registers we quantified the effects of simultaneous reproduction of these women on their offspring mortality. We found that the risk for offspring mortality before adulthood was increased by 23% if co-resident women reproduced within 2 years of each other, a risk that was not associated with the overall numbers of co-resident reproductive-aged women or children. Such costly competition may have promoted the evolution of birth scheduling, dispersal patterns and life-history traits including menopause that avoid resource competition with other reproductive females.
The social brain hypothesis predicts that humans have an average of about 150 relationships at any given time. Within this 150, there are layers of friends of an ego, where the number of friends in a layer increases as the emotional closeness decreases. Here we analyse a mobile phone dataset, firstly, to ascertain whether layers of friends can be identified based on call frequency. We then apply different clustering algorithms to break the call frequency of egos into clusters and compare the number of alters in each cluster with the layer size predicted by the social brain hypothesis. In this dataset we find strong evidence for the existence of a layered structure. The clustering yields results that match well with previous studies for the innermost and outermost layers, but for layers in between we observe large variability.
Using an agent-based model to study risk-pooling in herder dyads using rules derived from Maasai osotua (“umbilical cord”) relationships, Aktipis et al. (2011) found that osotua transfers led to more risk-pooling and better herd survival than both no transfers and transfers that occurred at frequencies tied to those seen in the osotua simulations. Here we expand this approach by comparing osotua-style transfers to another type of livestock transfer among Maasai known as esile (“debt”). In osotua, one asks if in need, and one gives in response to such requests if doing so will not threaten one’s own survival. In esile relationships, accounts are kept and debts must be repaid. We refer to these as “need-based” and “account-keeping” systems, respectively. Need-based transfers lead to more risk pooling and higher survival than account keeping. Need-based transfers also lead to greater wealth equality and are game theoretically dominant to account-keeping rules.
Personal social network size exhibits considerable variation in the human population and is associated with both physical and mental health status. Much of this inter-individual variation in human sociality remains unexplained from a biological perspective. According to the brain opioid theory of social attachment, binding of the neuropeptide β-endorphin to μ-opioid receptors in the central nervous system (CNS) is a key neurochemical mechanism involved in social bonding, particularly amongst primates. We hypothesise that a positive association exists between activity of the μ-opioid system and the number of social relationships that an individual maintains. Given the powerful analgesic properties of β-endorphin, we tested this hypothesis using pain tolerance as an assay for activation of the endogenous μ-opioid system. We show that a simple measure of pain tolerance correlates with social network size in humans. Our results are in line with previous studies suggesting that μ-opioid receptor signalling has been elaborated beyond its basic function of pain modulation to play an important role in managing our social encounters. The neuroplasticity of the μ-opioid system is of future research interest, especially with respect to psychiatric disorders associated with symptoms of social withdrawal and anhedonia, both of which are strongly modulated by endogenous opioids.
Moving in synchrony leads to cooperative behaviour and feelings of social closeness, and dance (involving synchronisation to others and music) may cause social bonding, possibly as a consequence of released endorphins. This study uses an experimental paradigm to determine which aspects of synchrony in dance are associated with changes in pain threshold (a proxy for endorphin release) and social bonding between strangers. Those who danced in synchrony experienced elevated pain thresholds, whereas those in the partial and asynchrony conditions experienced no analgesic effects. Similarly, those in the synchrony condition reported being more socially bonded, although they did not perform more cooperatively in an economic game. This experiment suggests that dance encourages social bonding amongst co-actors by stimulating the production of endorphins, but may not make people more altruistic. We conclude that dance may have been an important human behaviour evolved to encourage social closeness between strangers.
Although we share many aspects of our behaviour and biology with our primate cousins, humans are, nonetheless, different in one crucial respect: our capacity to live in the world of the imagination. This is reflected in two core aspects of our behaviour that are in many ways archetypal of what it is to be human: religion and story-telling. I shall show how these remarkable traits seem to have arisen as a natural development of the social brain hypothesis, and the underlying nature of primate sociality and cognition, as human societies have been forced to expand in size during the course of our evolution over the past 5 million years.
The social brain hypothesis has suggested that natural social network sizes may have a characteristic size in humans. This is determined in part by cognitive constraints and in part by the time costs of servicing relationships. Online social networking offers the potential to break through the glass ceiling imposed by at least the second of these, potentially enabling us to maintain much larger social networks. This is tested using two separate UK surveys, each randomly stratified by age, gender and regional population size. The data show that the size and range of online egocentric social networks, indexed as the number of Facebook friends, is similar to that of offline face-to-face networks. For one sample, respondents also specified the number of individuals in the inner layers of their network (formally identified as support clique and sympathy group), and these were also similar in size to those observed in offline networks. This suggests that, as originally proposed by the social brain hypothesis, there is a cognitive constraint on the size of social networks that even the communication advantages of online media are unable to overcome. In practical terms, it may reflect the fact that real (as opposed to casual) relationships require at least occasional face-to-face interaction to maintain them.
The availability of co-authorship data from large-scale electronic databases is paving the way for new analyses on human collaboration networks. The complex network of co-authorships can identify specific features that characterise the behaviour of researchers, and impact on their production and performance. In this paper, we analyse a large sample of data regarding scientific publications from Google Scholar. The aim of our analysis is to study a fundamental aspect of co-authorship networks, i.e. the structure of authors’ ego networks. Specifically, we highlight the existence of a hierarchical organisation of these networks in a series of concentric circles, quite similar to that found in general human social networks. In addition, we highlight some properties of the correlation between the ego network structure and the authors scientific productivity, measured in terms of h-index.
Although laughter is probably of deep evolutionary origin, the telling of jokes, being language-based, is likely to be of more recent origin within the human lineage. In language-based communication, speaker and listener are engaged in a process of mutually understanding each other's intentions (mindstates), with a conversation minimally requiring three orders of intentionality. Mentalizing is cognitively more demanding than non-mentalizing cognition, and there is a well-attested limit at five orders in the levels of intentionality at which normal adult humans can work. Verbal jokes commonly involve commentary on the mindstates of third parties, and each such mindstate adds an additional level of intentionality and its corresponding cognitive load. We determined the number of mentalizing levels in a sample of jokes told by well-known professional comedians and show that most jokes involve either three or five orders of intentionality on the part of the comedian, depending on whether or not the joke involves other individuals' mindstates. Within this limit there is a positive correlation between increasing levels of intentionality and subjective ratings of how funny the jokes are. The quality of jokes appears to peak when they include five or six levels of intentionality, which suggests that audiences appreciate higher mentalizing complexity whilst working within their natural cognitive constraints.
It has been proposed that singing evolved to facilitate social cohesion. However, it remains unclear whether bonding arises out of properties intrinsic to singing or whether any social engagement can have a similar effect. Furthermore, previous research has used one-off singing sessions without exploring the emergence of social bonding over time. In this semi-naturalistic study, we followed newly formed singing and non-singing (crafts or creative writing) adult education classes over seven months. Participants rated their closeness to their group and their affect, and were given a proxy measure of endorphin release, before and after their class, at three timepoints (months 1, 3 and 7). We show that although singers and non-singers felt equally connected by timepoint 3, singers experienced much faster bonding: singers demonstrated a significantly greater increase in closeness at timepoint 1, but the more gradual increase shown by non-singers caught up over time. This represents the first evidence for an 'ice-breaker effect' of singing in promoting fast cohesion between unfamiliar individuals, which bypasses the need for personal knowledge of group members gained through prolonged interaction. We argue that singing may have evolved to quickly bond large human groups of relative strangers, potentially through encouraging willingness to coordinate by enhancing positive affect.
Group dancing is a ubiquitous human activity that involves exertive synchronized movement to music. It is hypothesized to play a role in social bonding, potentially via the release of endorphins, which are analgesic and reward-inducing, and have been implicated in primate social bonding. We used a 2 × 2 experimental design to examine effects of exertion and synchrony on bonding. Both demonstrated significant independent positive effects on pain threshold (a proxy for endorphin activation) and in-group bonding. This suggests that dance which involves both exertive and synchronized movement may be an effective group bonding activity.
Significance
Touch is a powerful tool for communicating positive emotions. However, it has remained unknown to what extent social touch would maintain and establish social bonds. We asked a total of 1,368 people from five countries to reveal, using an Internet-based topographical self-reporting tool, those parts of their body that they would allow relatives, friends, and strangers to touch. These body regions formed relationship-specific maps in which the total area was directly related to the strength of the emotional bond between the participant and the touching person. Cultural influences were minor. We suggest that these relation-specific bodily patterns of social touch constitute an important mechanism supporting the maintenance of human social bonds.
Relationships are central to human life strategies and have crucial fitness consequences. Yet, at the same time, they incur significant maintenance costs that are rarely considered in either social psychological or evolutionary studies. Although many social psychological studies have explored their dynamics, these studies have typically focused on a small number of emotionally intense ties, whereas social networks in fact consist of a large number of ties that serve a variety of different functions. In this study, we examined how entire active personal networks changed over 18 months across a major life transition. Family relationships and friendships differed strikingly in this respect. The decline in friendship quality was mitigated by increased effort invested in the relationship, but with a striking gender difference: relationship decline was prevented most by increased contact frequency (talking together) for females but by doing more activities together in the case of males.
Visual attention functions as a filter to select environmental information for learning and memory, making it the first step in the eventual cascade of thought and action systems. Here, we review studies of typical and atypical visual attention development and explain how they offer insights into the mechanisms of adult visual attention. We detail interactions between visual processing and visual attention, as well as the contribution of visual attention to memory. Finally, we discuss genetic mechanisms underlying attention disorders and how attention may be modified by training.
Age and gender are two important factors that play crucial roles in the way
organisms allocate their social effort. In this study, we analyse a large
mobile phone dataset to explore the way lifehistory influences human sociality
and the way social networks are structured. Our results indicate that these
aspects of human behaviour are strongly related to the age and gender such that
younger individuals have more contacts and, among them, males more than
females. However, the rate of decrease in the number of contacts with age
differs between males and females, such that there is a reversal in the number
of contacts around the late 30s. We suggest that this pattern can be attributed
to the difference in reproductive investments that are made by the two sexes.
We analyse the inequality in social investment patterns and suggest that the
age and gender-related differences that we find reflect the constraints imposed
by reproduction in a context where time (a form of social capital) is limited.
This paper examines social network size in contemporary Western society based on the exchange of Christmas cards. Maximum
network size averaged 153.5 individuals, with a mean network size of 124.9 for those individuals explicitly contacted; these
values are remarkably close to the group size of 150 predicted for humans on the basis of the size of their neocortex. Age,
household type, and the relationship to the individual influence network structure, although the proportion of kin remained
relatively constant at around 21%. Frequency of contact between network members was primarily determined by two classes of
variable: passive factors (distance, work colleague, overseas) and active factors (emotional closeness, genetic relatedness).
Controlling for the influence of passive factors on contact rates allowed the hierarchical structure of human social groups
to be delimited. These findings suggest that there may be cognitive constraints on network size.
Homophily, the tendency for individuals to associate with those who are most similar to them, has been well documented. However, the influence of different kinds of similarity (e.g. relating to age, music taste, ethical views) in initial preferences for a stranger have not been compared. In the current study, we test for a relationship between sharing a variety of traits (i.e. having different kinds of similarity) with a stranger and the perceived likeability of that stranger. In two online experiments, participants were introduced to a series of virtual partners with whom they shared traits, and subsequently carried out activities designed to measure positivity directed towards those partners. Greater numbers of shared traits led to linearly increasing ratings of partner likeability and ratings on the Inclusion of Other in Self scale. We identified several consistent predictors of these two measures: shared taste in music, religion and ethical views. These kinds of trait are likely to be judged as correlates of personality or social group, and may therefore be used as proxies of more in-depth information about a person who might be socially more relevant.
We use data on frequencies of bi-directional posts to define edges (or relationships) in two Facebook datasets and a Twitter dataset and use these to create ego-centric social networks. We explore the internal structure of these networks to determine whether they have the same kind of layered structure as has been found in offline face-to-face networks (which have a distinctively scaled structure with successively inclusive layers at 5, 15, 50 and 150 alters). The two Facebook datasets are best described by a four-layer structure and the Twitter dataset by a five-layer structure. The absolute sizes of these layers and the mean frequencies of contact with alters within each layer match very closely the observed values from offline networks. In addition, all three datasets reveal the existence of an innermost network layer at ∼1.5 alters. Our analyses thus confirm the existence of the layered structure of ego-centric social networks with a very much larger sample (in total, >185,000 egos) than those previously used to describe them, as well as identifying the existence of an additional network layer whose existence was only hypothesised in offline social networks. In addition, our analyses indicate that online communities have very similar structural characteristics to offline face-to-face networks.
Previous empirical studies have suggested that language is primarily used to exchange social information, but our evidence on this derives mainly from English speakers. We present data from a study of natural conversations among Farsi (Persian) speakers in Iran and show that not only are conversation groups the same size as those observed in Europe and North America, but people also talk predominantly about social topics. We argue that these results reinforce the suggestion that language most likely evolved for the transmission of information about the social world. We also explore sex differences in conversational behavior: while the pattern is broadly similar between the sexes, men may be more sensitive than women are to discussing some topics in the presence of many other people.
What are the origins of intelligent behavior? The demands associated with living in complex social groups have been the favored explanation for the evolution of primate cognition in general and human cognition in particular. However, recent comparative research indicates that ecological variation can also shape cognitive abilities. I synthesize the emerging evidence that ‘foraging cognition’ – skills used to exploit food resources, including spatial memory, decision-making, and inhibitory control – varies adaptively across primates. These findings provide a new framework for the evolution of human cognition, given our species’ dependence on costly, high-value food resources. Understanding the origins of the human mind will require an integrative theory accounting for how humans are unique in both our sociality and our ecology.
The size of human social networks significantly exceeds the network that can be maintained by social grooming or touching in other primates. It has been proposed that endogenous opioid release after social laughter would provide a neurochemical pathway supporting long-term relationships in humans (Dunbar, 2012), yet this hypothesis currently lacks direct neurophysiological support. We used PET and the μ-opioid-receptor (MOR)-specific ligand [¹¹C]carfentanil to quantify laughter-induced endogenous opioid release in 12 healthy males. Before the social laughter scan, the subjects watched laughter-inducing comedy clips with their close friends for 30 min. Before the baseline scan, subjects spent 30 min alone in the testing room. Social laughter increased pleasurable sensations and triggered endogenous opioid release in thalamus, caudate nucleus, and anterior insula. In addition, baseline MOR availability in the cingulate and orbitofrontal cortices was associated with the rate of social laughter. In a behavioral control experiment, pain threshold—a proxy of endogenous opioidergic activation—was elevated significantly more in both male and female volunteers after watching laughter-inducing comedy versus non-laughter-inducing drama in groups. Modulation of the opioidergic activity by social laughter may be an important neurochemical pathway that supports the formation, reinforcement, and maintenance of human social bonds.
Significance
Social behavior in mammals is underpinned by a number of social neuropeptides. Most studies, however, focus on a single neuropeptide (often oxytocin), and invariably only in the context of reproductive relationships. Here, we examine the associations between the six main social neuropeptides (endorphins, oxytocin, vasopressin, dopamine, serotonin, and testosterone) and social indices in three separate social domains (disposition, dyadic/romantic relationships, and social network). We show that each neuropeptide is quite specific in its domain of influence, although endorphins and dopamine influence all three social domains. The results suggest that the social importance of endorphins may have been underestimated.
Apes understand false beliefs
We humans tend to believe that our cognitive skills are unique, not only in degree, but also in kind. The more closely we look at other species, however, the clearer it becomes that the difference is one of degree. Krupenye et al. show that three different species of apes are able to anticipate that others may have mistaken beliefs about a situation (see the Perspective by de Waal). The apes appear to understand that individuals have different perceptions about the world, thus overturning the human-only paradigm of the theory of mind.
Science , this issue p. 110 ; see also p. 39
Storytelling has played a major role in human evolution as a mechanism for engineering social cohesion. In large measure, this is because a shared worldview is an important basis for the formation not just of friendships but, more generally, of social communities. Storytelling thus provides the mechanism for the transmission of shared cultural icons and shared histories within a community. That being so, the effectiveness with which stories do their job is likely to be related to the storyteller?s ability to make challenging yet realistic stories without overtaxing the listeners? abilities to comprehend the narrative. I summarise some of the constraints likely to act on this both in terms of community size and organisation and in terms of cognition, and explore their implications for storytelling.
Although it has been shown that singing together encourages faster social bonding to a group compared with other activities, it is unknown whether this group-level “collective” bonding is associated with differences in the ties formed between individual singers and individuals engaging in other activities (“relational” bonding). Here we present self-report questionnaire data collected at three time points over the course of seven months from weekly singing and non-singing (creative writing and crafts) adult education classes. We compare the proportion of classmates with whom participants were connected and the social network structure between the singing and non-singing classes. Both singers and creative writers show a steeper increase over time in relational bonding measured by social network density and the proportion of their classmates that they could name, felt connected with, and talked to during class compared to crafters, but only the singers show rapid collective bonding to the class-group as a whole. Together, these findings indicate that the process of creating a unitary social group does not necessarily rely on the creation of personal relationships between its individual members. We discuss these findings in the light of social cohesion theory and social identity theory.
As humans age, they become more selective regarding their personal goals [1] and social partners [2]. Whereas the selectivity in goals has been attributed to losses in resources (e.g., physical strength) [3], the increasing focus on emotionally meaningful partners is, according to socioemotional selectivity theory, driven by the awareness of one's decreasing future lifetime [2]. Similar to humans, aging monkeys show physical losses [4] and reductions in social activity [2, 5-7]. To disentangle a general resource loss and the awareness of decreasing time, we combined field experiments with behavioral observations in a large age-heterogeneous population of Barbary macaques (Macaca sylvanus) at La Forêt des Singes. Novel object tests revealed a loss of interest in the nonsocial environment in early adulthood, which was modulated by the availability of a food reward. Experiments using vocal and visual representations of social partners indicated that monkeys maintained an interest in social stimuli and a preferential interest in friends and socially important individuals into old age. Old females engaged in fewer social interactions, although other group members continued to invest in relationships with them. Consequently, reductions in sociality were not due to a decrease in social interest. In conclusion, some of the motivational shifts observed in aging humans, particularly the increasing focus on social over nonsocial stimuli, may occur in the absence of a limited time perspective and are most likely deeply rooted in primate evolution. Our findings highlight the value of nonhuman primates as valuable models for understanding human aging [8, 9]. download for free here: http://authors.elsevier.com/a/1TOlQ3QW8ResVQ
Conversations are ubiquitous and central elements of daily life. Yet a fundamental feature of conversation remains a mystery: It is genuinely difficult to maintain an everyday conversation with more than four speakers. Why? We introduce a “mentalizing explanation” for the conversation size constraint, which suggests that humans have a natural limit on their ability to model the minds of others, and that this limit, in turn, shapes the sizes of everyday conversations. Using established methodologies for investigating conversation size, we pit this mentalizing hypothesis against two competing explanations—that the size of a conversation is limited by a short-term memory capacity (limiting the factual information we process) or by an auditory constraint (speakers need to be able to hear what each other are saying)—in conversations drawn from a real-world college campus and from Shakespearean plays. Our results provide support for the mentalizing hypothesis and also render alternative accounts less plausible.
Human conversation groups have a characteristic size limit at around four individuals. Although mixed-sex social groups can be significantly larger than this, census data on casual social groups suggest that there is a fractal pattern of fission in conversations when social group size is a multiple of this value. This study suggests that, as social group size increases beyond four, there is a tendency for sexual segregation to occur resulting in an increasing frequency of single-sex conversational subgroups. It is not clear why conversations fragment in this way, but a likely explanation is that sex differences in conversational style result in women (in particular) preferring to join all-female conversations when a social group is large enough to allow this.
In both modern humans and non-human primates, time and cognitive constraints place an upper bound on the number of social relationships an individual can maintain at a given level of intensity. Similar constraints are likely to have operated throughout hominin evolution, shaping the size and structure of social networks. One of the key trends in human evolution, alongside an increase in brain size, is likely to have been an increase in group size, resulting in a larger number of social relationships that would have to be maintained over time. The network approach demonstrates that relationships should not be viewed as dyadic ties between two individuals, but as embedded within a larger network of ties between network members. This network can act as a scaffold to the dyadic tie, reducing the time and cognitive costs of maintaining the relationship. Together with relationships based on kinship, this scaffolding may have allowed for larger group sizes to be maintained among hominins than would be possible if such networks were based purely on dyadic ties between individuals.
Conventional wisdom over the past 160 years in the cognitive and neurosciences has assumed that brains evolved to process factual information about the world. Most attention has therefore been focused on such features as pattern recognition, color vision, and speech perception. By extension, it was assumed that brains evolved to deal with essentially ecological problem-solving tasks. 1.
Human quantitative boundaries for sympathizing are perceived as having been roughly established during human evolution into social beings. Data obtained on 125 American subjects are viewed as consistent with this highly speculative notion.
Socioemotional selectivity theory contends that as people become increasingly aware of limitations on future time, they are increasingly motivated to be more selective in their choice of social partners, favoring emotionally meaningful relationships over peripheral ones. The theory hypothesizes that because age is negatively associated with time left in life, the social networks of older people contain fewer peripheral social partners than those of their younger counterparts. This study tested the hypothesis among African Americans and European Americans, two ethnic groups whose social structural resources differ. Findings confirm the hypothesis. Across a wide age range (18 to 94 years old) and among both ethnic groups, older people report as many emotionally close social partners but fewer peripheral social partners in their networks as compared to their younger counterparts. Moreover, a greater percentage of very close social partners in social networks is related to lower levels of happiness among the young age group, but not among the older age groups. Implications of findings for adaptive social functioning across the life span are discussed.
Human attachment behavior mediates establishment and maintenance of social relationships. Adult attachment characteristically varies on anxiety and avoidance dimensions, reflecting the tendencies to worry about the partner breaking the social bond (anxiety) and feeling uncomfortable about depending on others (avoidance). In primates and other mammals, the endogenous μ-opioid system is linked to long-term social bonding, but evidence of its role in human adult attachment remains more limited. We used in vivo positron emission tomography to reveal how variability in μ-opioid receptor (MOR) availability is associated with adult attachment in humans. We scanned 49 healthy subjects using a MOR-specific ligand [(11) C]carfentanil and measured their attachment avoidance and anxiety with the Experiences in Close Relationships-Revised scale. The avoidance dimension of attachment correlated negatively with MOR availability in the thalamus and anterior cingulate cortex, as well as the frontal cortex, amygdala, and insula. No associations were observed between MOR availability and the anxiety dimension of attachment. Our results suggest that the endogenous opioid system may underlie interindividual differences in avoidant attachment style in human adults, and that differences in MOR availability are associated with the individuals' social relationships and psychosocial well-being. Hum Brain Mapp, 2015. © 2015 Wiley Periodicals, Inc.
© 2015 Wiley Periodicals, Inc.