Peer interaction in infant chimpanzees

The peer interactions of 6 infant chimpanzees (Pan troglodytes) ranging in age from 18 to 50 months were observed in a seminatural context. The infants and their mothers lived as members of a captive social group at the Yerkes Regional Primate Research Center. An analysis of contact initiations between infants indicated that the most preferred peer interactant was the youngest and the least preferred was the oldest infant. Infants also initiated more interactions with the offspring of adults that had the closest relationships with both themselves and their mothers. These results indicate that a number of factors may influence the peer affiliations of infant chimpanzees, including the age of the infant and the mother's social relationships.     

Dominance hierarchy and social relationships in a group of Captive black-and-white snub-nosed monkeys (Rhinopithecus bieti)

Different types of dominance hierarchies reflect different social relationships in primates. In this study, we clarified the hierarchy and social relationships in a one-male unit of captive Rhinopithecus bieti observed between August 1998 and March 1999. Mean frequency of agonistic behaviour among adult females was 0.13 interactions per hour. Adult females exhibited a linear hierarchy with a reversal of 10.9%, indicating an unstable relationship; therefore, R. bieti appears to be a relaxed/tolerant species. The lack of a relationship between the agonistic ratio of the adult male towards adult females and their ranks indicated that males did not show increased aggression towards low-ranking females. Differentiated female affiliative relationships were loosely formed in terms of the male, and to some extent influenced by female estrus, implying that relationships between the male and females is influenced by estrus and not rank alone. A positive correlation between the agonistic ratio of adult females and their ranks showed that the degree to which one female negatively impacted others decreased with reduction in rank. Similarly, a positive correlation between the agonistic ratio of females and differences in rank suggests that a female had fewer negative effects on closely ranked individuals than distantly ranked ones. These data indicate that rank may influence relationships between females. A steeper slope of regression between the agonistic ratio and inter-female rank differences indicated that the extent of the power difference in high-ranking females exerting negative effects on low-ranking ones was larger during the mating season than the birth season, suggesting that rank may influence the mating success of females.     

Social Network Analysis Reveals the Negative Effects of Attention-Deficit/Hyperactivity Disorder (ADHD) Symptoms on Friend-Based Student Networks

Introduction

Social network analysis has emerged as a promising tool in modern social psychology. This method can be used to examine friend-based social relationships in terms of network theory, with nodes representing individual students and ties representing relationships between students (e.g., friendships and kinships). Using social network analysis, we investigated whether greater severity of ADHD symptoms is correlated with weaker peer relationships among elementary school students.

Methods

A total of 562 sixth-graders from two elementary schools (300 males) provided the names of their best friends (maximum 10 names). Their teachers rated each student’s ADHD symptoms using an ADHD rating scale.

Results

The results showed that 10.2% of the students were at high risk for ADHD. Significant group differences were observed between the high-risk students and other students in two of the three network parameters (degree, centrality and closeness) used to assess friendship quality, with the high-risk group showing significantly lower values of degree and closeness compared to the other students. Moreover, negative correlations were found between the ADHD rating and two social network analysis parameters.

Conclusion

Our findings suggest that the severity of ADHD symptoms is strongly correlated with the quality of social and interpersonal relationships in students with ADHD symptoms.     

Social relationships of nulliparous young adult females beyond the ordinary age of the first birth in a free-ranging troop of Japanese macaques (Macaca fuscata)

We describe the social relationships of young adult female Japanese macaques (Macaca fuscata) in a free-ranging troop in Arashiyama, Kyoto, Japan, who remained nulliparous beyond the ordinary age of first birth because of contraceptive administration. We observed 12 young nulliparous adult females (6–9 years old) for 270 h and 10 min from 2 February to 5 October 2010. The majority maintained close relationships with their mothers through proximity and grooming, whereas a few had very infrequent social interactions with their mothers. Most had asymmetrical grooming relationships; the grooming they received from unrelated adult females was less than the grooming they gave. Young adult females who had less frequent interactions with their mothers by either proximity or grooming received more grooming from a larger number of unrelated adult females than did those who had more frequent social interactions with their mothers. These results indicate that most young adult females who remained nulliparous beyond the ordinary age of first birth tended to maintain close relationships with their mothers, and their grooming relationships with unrelated adult females were inversely related to the degree of closeness with their mothers.     

Asymmetry and Dimensions of Relationship Quality in the Japanese Macaque (<Emphasis Type="Italic">Macaca fuscata yakui</Emphasis>)

Cords and Aureli (2000) proposed that relationship quality can be described by three components, i.e., value, security, and compatibility, based on the benefits social partners receive from their relationship and on how likely it is for them to maintain a stable friendly relationship over time. We aimed to examine whether this 3-components structure can describe social relationships and to investigate the degree of asymmetry of social relationships. We used the Japanese macaque as our model species, as group members may form strong social relationships with one another. We collected 359.2 h of focal samples, on 21 monkeys, and ran a principal component analysis (PCA) on dyadic scores for 9 variables measuring social relationships, e.g., grooming or aggression. This PCA gave 3 components. However, a second PCA run on scores per individual, i.e. for each variable and dyad we obtained 1 score for the actor and 1 for the receiver of behavior, gave a 5-component structure. We interpreted this result as evidence of the asymmetric nature of social relationships, in terms of the frequency and type of behavior exchanged between social partners, in the Japanese macaque. This interpretation was confirmed by the low correlation coefficients between behaviors given and received within a dyad. Overall these results provide mixed support for the 3-components structure predicted by Cords and Aureli (2000). They also show that social relationships may be largely asymmetric and that this asymmetry should be considered in studies on social behavior.     

White-faced capuchin monkeys show triadic awareness in their choice of allies

The social intelligence hypothesis, which holds that social challenges have selected for increased intelligence and social skills, has been supported by evidence that, in catarrhine primates, individuals know about the characteristics of groupmates' social relationships. Evidence for such ‘triadic awareness’ has not been sought for platyrrhine primates, although two platyrrhine genera, capuchins, Cebus, and squirrel monkeys, Saimiri, are among the most highly encephalized primates. We examined patterns of coalitionary recruitment in wild white-faced capuchins, C. capucinus. Analyses have shown that more dominant individuals are more likely to join aggressive coalitions than low-rankers, and that individuals preferentially support those with whom they have stronger affiliative relationships. Data from 110 fights, analysed using simulation techniques that produced distributions of results expected under null hypotheses, revealed that contestants preferentially solicited prospective coalition partners that (1) were dominant to their opponents, and (2) had better social relationships (higher ratios of affiliative/cooperative interactions to agonistic interactions) with themselves than with their opponents. Further analyses showed that soliciting dominant partners could be explained by either of two simpler rules, ‘Solicit an ally that outranks yourself’ or ‘Solicit the highest-ranking available individual’. However, soliciting partners with better social relationships appears to indicate triadic awareness, because subjects did not preferentially solicit the nearby individual with whom they shared the highest-quality social relationship. Effects of relative relationship quality on coalition solicitation decisions were independent of effects of dominance rank.     

The Pet Factor - Companion Animals as a Conduit for Getting to Know People,Friendship Formation and Social Support

Background

While companion animals have been previously identified as a direct source of companionship and support to their owners, their role as a catalyst for friendship formation or social support networks among humans has received little attention. This study investigated the indirect role of pets as facilitators for three dimensions of social relatedness; getting to know people, friendship formation and social support networks.

Methods

A telephone survey of randomly selected residents in four cities, one in Australia (Perth; n = 704) and three in the U.S. (San Diego, n = 690; Portland, n = 634; Nashville, n = 664) was conducted. All participants were asked about getting to know people within their neighborhood. Pet owners were asked additional questions about the type/s of pet/s they owned, whether they had formed friendships as a result of their pet, and if they had received any of four different types of social support from the people they met through their pet.

Results

Pet owners were significantly more likely to get to know people in their neighborhood than non-pet owners (OR 1.61; 95%CI: 1.30, 1.99). When analyzed by site, this relationship was significant for Perth, San Diego and Nashville. Among pet owners, dog owners in the three U.S. cities (but not Perth) were significantly more likely than owners of other types of pets to regard people whom they met through their pet as a friend (OR 2.59; 95%CI: 1.94, 3.46). Around 40% of pet owners reported receiving one or more types of social support (i.e. emotional, informational, appraisal, instrumental) via people they met through their pet.

Conclusion

This research suggests companion animals can be a catalyst for several dimensions of human social relationships in neighborhood settings, ranging from incidental social interaction and getting to know people, through to formation of new friendships. For many pet owners, their pets also facilitated relationships from which they derived tangible forms of social support, both of a practical and emotionally supportive nature. Given growing evidence for social isolation as a risk factor for mental health, and, conversely, friendships and social support as protective factors for individual and community well-being, pets may be an important factor in developing healthy neighborhoods.     

Social monitoring via close calls in meerkats

Social monitoring of the actions of group members is thought to be a key development associated with group living. Humans constantly monitor the behaviour of others and respond to them in a flexible way depending on past interactions and the current social context. While other primates have also been reported to change their behaviour towards other group members flexibly based on the current state of their relationship, empirical evidence is typically linked to contextually specific events such as aggressive or reproductive interactions. In the cooperatively breeding meerkat (Suricata suricatta), we investigated whether subordinate females use frequently emitted, non-agonistic close calls to monitor the location of the dominant female and whether they subsequently adjust their response based on recent social interactions during conflict and non-conflict periods. Subjects discriminated between the close calls of the dominant female and control playbacks, responding by approaching the loudspeaker and displaying submissive behaviour only if they were currently threatened by eviction. Our results suggest that meerkats assess the risk for aggressive interactions with close associates depending on social circumstances, and respond accordingly. We argue that social monitoring based on non-agonistic cues is probably a common mechanism in group-living species that allows the adjustment of behaviour depending on variation in relationships.     

On Disciplinary Fragmentation and Scientific Progress

Why are some scientific disciplines, such as sociology and psychology, more fragmented into conflicting schools of thought than other fields, such as physics and biology? Furthermore, why does high fragmentation tend to coincide with limited scientific progress? We analyzed a formal model where scientists seek to identify the correct answer to a research question. Each scientist is influenced by three forces: (i) signals received from the correct answer to the question; (ii) peer influence; and (iii) noise. We observed the emergence of different macroscopic patterns of collective exploration, and studied how the three forces affect the degree to which disciplines fall apart into divergent fragments, or so-called “schools of thought”. We conducted two simulation experiments where we tested (A) whether the three forces foster or hamper progress, and (B) whether disciplinary fragmentation causally affects scientific progress and vice versa. We found that fragmentation critically limits scientific progress. Strikingly, there is no effect in the opposite causal direction. What is more, our results shows that at the heart of the mechanisms driving scientific progress we find (i) social interactions, and (ii) peer disagreement. In fact, fragmentation is increased and progress limited if the simulated scientists are open to influence only by peers with very similar views, or when within-school diversity is lost. Finally, disciplines where the scientists received strong signals from the correct answer were less fragmented and experienced faster progress. We discuss model’s implications for the design of social institutions fostering interdisciplinarity and participation in science.     

Relations between group size and composition and feeding competition in mountain gorilla groups

The intensity and patterning of interference competition for food within mountain gorilla (Pan gorilla beringei) social groups is influenced in several ways by group size and composition and varies within and across age/sex classes. Data on 251 spatial displacemtnts associated with feeding, collected during a 17-month study of mountain gorilla feeding ecology, show that overall displacement rates and displacement rates for individuals were positively correlated with social group size. Silverback males were responsible for a disproportionately high number of displacements. Adult females also were involved in competitive interactions over food more often than expected from their representation in groups, and had feeding bouts interrupted disproportionately often, principally by other females and by silverbacks. Competitive relationships between females varied in association with female dominance rank and age, but were not clearly associated with relatedness between females. The results support the argument that social foraging entails a cost which is proportional to group size and which falls particularly on adult females. The comparatively low rates of competitive interactions, however, suggest that this cost is relatively low, and that female mountain gorillas sacrifice little in terms of feeding efficiency by living in social groups.     

Chimaeric load among sympatric social bacteria increases with genotype richness

The total productivity of social groups can be determined by interactions among their constituents. Chimaeric load—the reduction of group productivity caused by antagonistic within-group heterogeneity—may be common in heterogeneous microbial groups due to dysfunctional behavioural interactions between distinct individuals. However, some instances of chimaerism in social microbes can increase group productivity, thus making a general relationship between chimaerism and group-level performance non-obvious. Using genetically similar strains of the soil bacterium Myxococcus xanthus that were isolated from a single centimetre-scale patch of soil, we tested for a relationship between degree of chimaerism (genotype richness) and total group performance at social behaviours displayed by this species. Within-group genotype richness was found to correlate negatively with total group performance at most traits examined, including swarming in both predatory and prey-free environments and spore production during development. These results suggest that interactions between such neighbouring strains in the wild will tend to be mutually antagonistic. Negative correlations between group performance and average genetic distance among group constituents at three known social genes were not found, suggesting that divergence at other loci that govern social interaction phenotypes is responsible for the observed chimaeric load. The potential for chimaeric load to result from co-aggregation among even closely related neighbours may promote the maintenance and strengthening of kin discrimination mechanisms, such as colony-merger incompatibilities observed in M. xanthus. The findings reported here may thus have implications for understanding the evolution and maintenance of diversity in structured populations of soil microbes.     

The coevolutionary dynamics of obligate ant social parasite systems--between prudence and antagonism

In this synthesis we apply coevolutionary models to the interactions between socially parasitic ants and their hosts. Obligate social parasite systems are ideal models for coevolution, because the close phylogenetic relationship between these parasites and their hosts results in similar evolutionary potentials, thus making mutual adaptations in a stepwise fashion especially likely to occur. The evolutionary dynamics of host-parasite interactions are influenced by a number of parameters, for example the parasite's transmission mode and rate, the genetic structure of host and parasite populations, the antagonists' migration rates, and the degree of mutual specialisation. For the three types of obligate ant social parasites, queen-tolerant and queen-intolerant inquilines and slavemakers, several of these parameters, and thus the evolutionary trajectory, are likely to differ. Because of the fundamental differences in lifestyle between these social parasite systems, coevolution should further select for different traits in the parasites and their hosts. Queen-tolerant inquilines are true parasites that exert a low selection pressure on their host, because of their rarity and the fact that they do not conduct slave raids to replenish their labour force. Due to their high degree of specialisation and the potential for vertical transmission, coevolutionary theory would predict interactions between these workerless parasites and their hosts to become even more benign over time. Queen-intolerant inquilines that kill the host queen during colony take-over are best described as parasitoids, and their reproductive success is limited by the existing worker force of the invaded host nest. These parasites should therefore evolve strategies to best exploit this fixed resource. Slavemaking ants, by contrast, act as parasites only during colony foundation, while their frequent slave raids follow a predator prey dynamic. They often exploit a number of host species at a given site, and theory predicts that their associations are best described in terms of a highly antagonistic coevolutionary arms race.     

Oxytocin and vulnerable romantic relationships

Oxytocin (OT) has been implicated in the formation and maintenance of various social relationships, including human romantic relationships. Competing models predict, alternatively, positive or negative associations between naturally-occurring OT levels and romantic relationship quality. Empirical tests of these models have been equivocal. We propose a novel hypothesis (‘Identify and Invest’) that frames OT as an allocator of psychological investment toward valued, vulnerable relationships, and test this proposal in two studies. In one sample of 75 couples, and a second sample of 148 romantically involved individuals, we assess facets of relationships predicting changes in OT across a thought-writing task regarding one's partner. In both studies, participants' OT change across the task corresponded positively with multiple dimensions of high relationship involvement. However, increases in participants' OT also corresponded to their partners reporting lower relationship involvement. OT increases, then, reflected discrepancies between assessments of self and partner relationship involvement. These findings are robust in a combined analysis of both studies, and do not significantly differ between samples. Collectively, our findings support the ‘Identify and Invest’ hypothesis in romantic couples, and we argue for its relevance across other types of social bonds.     

An Agent-Based Model of Private Woodland Owner Management Behavior Using Social Interactions,Information Flow,and Peer-To-Peer Networks

Privately owned woodlands are an important source of timber and ecosystem services in North America and worldwide. Impacts of management on these ecosystems and timber supply from these woodlands are difficult to estimate because complex behavioral theory informs the owner’s management decisions. The decision-making environment consists of exogenous market factors, internal cognitive processes, and social interactions with fellow landowners, foresters, and other rural community members. This study seeks to understand how social interactions, information flow, and peer-to-peer networks influence timber harvesting behavior using an agent-based model. This theoretical model includes forested polygons in various states of ‘harvest readiness’ and three types of agents: forest landowners, foresters, and peer leaders (individuals trained in conservation who use peer-to-peer networking). Agent rules, interactions, and characteristics were parameterized with values from existing literature and an empirical survey of forest landowner attitudes, intentions, and demographics. The model demonstrates that as trust in foresters and peer leaders increases, the percentage of the forest that is harvested sustainably increases. Furthermore, peer leaders can serve to increase landowner trust in foresters. Model output and equations will inform forest policy and extension/outreach efforts. The model also serves as an important testing ground for new theories of landowner decision making and behavior.     

Ecological and social determinants of birth intervals in baboons

Birth rates in primates have long been proposed to result froman interaction between ecological and social factors. We analyzeda variety of social and environmental variables to determinewhich ones best explain the observed variation in interbirthintervals across 14 baboon populations. Both the number offemales in the group and mean annual temperature were foundto be important, and a multivariate equation containing thequadratic components of both these variables accounts for almostall the observed variance in interbirth intervals. The quadraticrelationship with temperature is explained in terms of theenergetic costs of maintaining a stable body temperature at both low and high temperatures. The quadratic relationship withnumber of females results from relationships with both foodavailability and the costs of increasing intragroup competitionas group size increases. Although females may be able to exerta certain degree of choice in their reproductive schedulingdecisions, they are ultimately constrained by limits imposedupon them by the complex interactions between their ecologicaland demographic environment.     

Exploring the components, asymmetry and distribution of relationship quality in wild Barbary macaques (Macaca sylvanus)

Social relationships between group members are a key feature of many animal societies. The quality of social relationships has been described by three main components: value, compatibility and security, based on the benefits, tenure and stability of social exchanges. We aimed to analyse whether this three component structure could be used to describe the quality of social relationships in wild Barbary macaques (Macaca sylvanus). Moreover, we examined whether relationship quality was affected by the sex, age and rank differences between social partners, and investigated the asymmetric nature of social relationships. We collected over 1,900 hours of focal data on seven behavioural variables measuring relationship quality, and used principal component analysis to investigate how these variables clustered together. We found that relationship quality in wild Barbary macaques can be described by a three component structure that represents the value, compatibility and security of a relationship. Female-female dyads had more valuable relationships and same-age dyads more compatible relationships than any other dyad. Rank difference had no effect on the quality of a social relationship. Finally, we found a high degree of asymmetry in how members of a dyad exchange social behaviour. We argue that the asymmetry of social relationships should be taken into account when exploring the pattern and function of social behaviour in animal societies.