Cohesive Social Groups Research Articles

Connecting global health interventions and lived experiences: suspending ‘normality’ at funerals in rural Tanzania

In this paper, we use the funeral space and its liminal nature as a milieu for exploring how a ‘modern’ health intervention, the mosquito bednet, is negotiated by its recipients in relation to its (non)-usage in such spaces. With a focus on sleeping arrangements at funerals and drawing on empirical data from participants living in rural southern Tanzania, we discuss how the bednet is linked to the notion of being unsympathetic to the death. Viewed as a symbol of modernity and a reflection of wealth and individual pride, the bednet becomes physically and symbolically inappropriate in the more sacred, ‘in-between’ site of the funeral. We also uncover how risk perceptions regarding malaria transmission are re-cast in funeral spaces, with socio-cultural practices and health-related behaviours being simultaneously ‘risky’ for individual mourners and reinforcing in terms of group social cohesion. As individual mourners' concerns about malaria risks are suspended, notions of pain and discomfort come to the fore as part of the mourning process and respect for the deceased.

Development-Induced Displacement and Its Impacts on the Livelihoods of Poor Urban Households in Bahir Dar, North Western Ethiopia

This article attempts to explore urban relocation impacts on the livelihoods of poor households displaced by a development project in Bahir Dar city in northwestern Ethiopia. Qualitative methods were used to generate the necessary data. The findings identified that the urban relocation caused a variety of livelihood risks such as loss of home or shelter, lack of urban infrastructures such as road facilities, electricity, job opportunites, potable water services and cash compensation for rehousing, as well as landlessness and separation of small cohesive social groups (notably coffee members). Though IDPs are exposed to various livelihood challenges because of a lack of addressing environmental impact assessment recommendations, those who received housing land are partly happy with owning legally recognised urban land. Currently, IDPs are the owners of the land registered by the municipality. The study urges the need to assess and address the unmet needs of poor urban residents as well as the environmental impact of urban development projects.

Influence of social interactions on the response to social cues in spiderlings

Mutual attraction is one central mechanism involved in the maintenance of cohesion in group-living species and relies on a modulation of individual behaviours in response to the presence of conspecifics. Social markers left in the environment can play an additional role in the modulation of behaviours and can substantially impact the cohesion of social groups. In this study, our objective was to examine the interplay between the presence of social cues and the individual responsiveness to conspecifics in spiderlings. Spiders are relevant models to address this issue as juveniles lay silk draglines during their displacements and display a transient gregarious phase. We introduced single or pairs of spiderlings in an experimental arena covered with different amounts of silk. Our results indicated that the probability of moving increased with the presence and the quantity of silk in single individuals. In contrast, we did not find evidence for any influence of the quantity of silk on interacting spiderlings and we showed that social interactions inhibited the individual response to social markers. Overall, our study suggests that the influence of social interactions on the modulation of individual behaviours prevailed over the presence of social cues. We discussed our results in the framework of chemical communication to explain the interplay between social cues and social interactions on the modulation of individual behaviours.

Leadership of herd progressions in the Thornicroft's giraffe of Zambia

AbstractIn cohesive social groups, travel progressions are often led by dominant or older individuals, but the leadership traits of individuals residing in flexible social systems are poorly known. Giraffe reside in herds characterized by fission–fusion dynamics frequently mediated by kinship. We analyzed 41 years (1971–2012) of longitudinal data collected from a community of Thornicroft's giraffe (Giraffa camelopardalis thornicrofti) living around South Luangwa National Park, Zambia, to assess the characteristics of herd leaders. Movement of giraffe in a single file progression was not associated with either season or time of day, but progressions were significantly more likely to occur when giraffe traveled in open areas. The oldest female in a herd was significantly more likely to be at the front position than expected, occupying the leadership niche on 79% of observations. We reason that matriarchal leadership in giraffe, as in African elephants, Loxodonta africana, is associated with resource learning. Giraffe societies are constructed on a heretofore unrecognized foundation that integrates relatedness and familiarity with matriarchal leadership in herd movement.

Long-lasting, kin-directed female interactions in a spatially structured wild boar social network.

Individuals can increase inclusive fitness benefits through a complex network of social interactions directed towards kin. Preferential relationships with relatives lead to the emergence of kin structures in the social system. Cohesive social groups of related individuals and female philopatry of wild boar create conditions for cooperation through kin selection and make the species a good biological model for studying kin structures. Yet, the role of kinship in shaping the social structure of wild boar populations is still poorly understood. In the present study, we investigated spatio-temporal patterns of associations and the social network structure of the wild boar Sus scrofa population in Białowieża National Park, Poland, which offered a unique opportunity to understand wild boar social interactions away from anthropogenic factors. We used a combination of telemetry data and genetic information to examine the impact of kinship on network cohesion and the strength of social bonds. Relatedness and spatial proximity between individuals were positively related to the strength of social bond. Consequently, the social network was spatially and genetically structured with well-defined and cohesive social units. However, spatial proximity between individuals could not entirely explain the association patterns and network structure. Genuine, kin-targeted, and temporarily stable relationships of females extended beyond spatial proximity between individuals while males interactions were short-lived and not shaped by relatedness. The findings of this study confirm the matrilineal nature of wild boar social structure and show how social preferences of individuals translate into an emergent socio-genetic population structure.

ECOLOGICAL DRIVERS OF ANTIPREDATOR DEFENSES IN CARNIVORES

Mammals have evolved several morphological and behavioral adaptations to reduce the risk of predation, but we know little about the ecological factors that favor their evolution. For example, some mammalian carnivores have the ability to spray noxious anal secretions in defense, whereas other species lack such weaponry but may instead rely on collective vigilance characteristic of cohesive social groups. Using extensive natural history data on 181 species in the order Carnivora, we created a new estimate of potential predation risk from mammals and birds of prey and used comparative phylogenetic methods to assess how different sources of predation risk and other ecological variables influence the evolution of either noxious weaponry or sociality in this taxon. We demonstrate that the evolution of enhanced spraying ability is favored by increased predation risk from other mammals and by nocturnality, but the evolution of sociality is favored by increased predation risk from birds of prey and by diurnality, which may allow for enhanced early visual detection. These results suggest that noxious defenses and sociality are alternative antipredator strategies targeting different predator guilds under different lighting conditions.

Conversion disorder and mass psychogenic illness in child neurology

A common problem faced by neurologists is the existence of disorders that present with neurological symptoms but do not have identifiable neurological bases. Conversion disorder is the most common of these disorders. In some situations, members of a cohesive social group will develop the same or similar symptoms. This review discusses conversion disorder in children, with an emphasis on function movement disorders. It also reviews a recent occurrence of mass psychogenic illness in New York State with discussion of the key features of mass psychogenic illness.

Transitioning from unstable to stable colony growth in the desert leafcutter ant Acromyrmex versicolor

Like organisms, cohesive social groups such as insect colonies grow from a few individuals to large and complex integrated systems. Growth is driven by the interplay between intrinsic growth rates and environmental factors, particularly nutritional input. Ecologically inspired population growth models assume that this relationship remains constant until maturity, but more recent models suggest that it should be less stable at small colony sizes. To test this empirically, we monitored worker population growth and fungal development in the desert leafcutter ant, Acromyrmex versicolor, over the first 6 months of colony development. As a multitrophic, symbiotic system, leafcutter colonies must balance efforts to manage both fungus production and the growth of the ants consuming it. Both ants and fungus populations grew exponentially, but the shape of this relationship transitioned at a size threshold of 89 ± 9 workers. Above this size, colony mortality plummeted and colonies shifted from hypometric to hypermetric growth, with a distinct stabilization of the relationship between the worker population and fungus. Our findings suggest that developing colonies undergo key changes in organizational structure and stability as they grow, with a resulting positive transition in efficiency and robustness.

Who is coordinating collective movements in black and gold howler monkeys?

Decisions about when and where to travel are likely to have a strong influence on the feeding, ecology, and foraging strategies of individual primates living in a cohesive social group. Specifically, given differences in age, sex, reproductive status, or social dominance, particular group members may benefit from remaining at their present location while others may benefit from traveling to another area of their range to feed or rest. In this study, we present data on movement coordination in two groups of wild black and gold howler monkeys inhabiting Isla Brasilera (27º 20'S and 58º 40'W) in northern Argentina. We examine how factors such as sex, age, reproductive status, and dominance affect patterns of group movement coordination at feeding or resting sites, and in the context of intergroup encounters. Two groups were followed five days a month from sunrise to sunset during June to November 2004. Using focal and scan sampling techniques, we recorded 262 group displacements, the identity of the individual initiating and leading displacement, and the identity of the first individual to arrive at feeding, resting, or intergroup encounter sites. We found that overall age was the only factor that influenced group coordination: adults led more often (94.5%) than immature individuals (5.5%) in both groups. We did not find differences among adults. However, we found that males lead more often than females at intergroup encounters, consistent with the male-mate defense hypothesis. The distributed leadership pattern among adults observed in this study may suggest that adult individuals make equally shared consensus decisions. This pattern should be further examined using this individual-level approach in other populations of black and gold howlers, other species of howlers, and in other atelines in which within-group social tolerance is the rule rather than the exception.

Looking Similar Promotes Group Stability in a Game-Based Virtual Community.

Online support groups are popular Web-based resources that provide tailored information and peer support through virtual communities and fulfill the users' needs for empowerment and belonging. However, the therapeutic potential of online support groups is at present limited by the lack of systematic research on the cognitive mechanisms underlying social group cohesion in virtual communities. We might increase the benefits of participation in online support groups if we gain more insight into the factors that promote long-term commitment to peer support. One approach to foster the therapeutic potential of online support groups could be to increase social selection based on visual similarity. We performed a case study using the popular virtual setting of "World of Warcraft" (Blizzard Entertainment, Irvine, CA). We monitored the social dynamics of a virtual community composed of avatars whose appearance was identical during a period of 3 months, biweekly, for a total of 24 measures. We observed that this homogeneous community displayed a very high level of group stability over time in terms of the total number of members, the number of members that stayed the same, and the number of arrivals and departures, despite the fact that belonging to a heterogeneous group typically favors the success of the group with respect to game progression. Our results confirm that appearance can trigger social selection in online virtual communities. Displaying a similar appearance could be one way to strengthen social bonds among peers who share various health and well-being issues. Thus, the therapeutic potential of online support groups could be promoted through visual cohesion.

Policing Effectiveness Depends on Relatedness and Group Size

Cohesion of social groups requires the suppression of individual selfishness. Indeed, worker egg laying in insect societies is usually suppressed or punished through aggression and egg removal. The effectiveness of such "policing" is expected to increase with decreasing relatedness, as inclusive fitness of group members is more strongly affected by selfish worker reproduction when group members are less closely related to each other. As inclusive fitness is also influenced by the costs and benefits of helping, the effectiveness of policing should decrease with increasing colony size, because the costs for the whole colony from selfish worker reproduction are proportionally reduced in large groups. Here, we show that policing effectiveness in colonies of the ant Temnothorax unifasciatus is low in large groups and high in small groups when relatedness is high. When we experimentally decreased the relatedness in groups, the policing effectiveness reached the same high level as in small, highly related groups, irrespective of group size. Therefore, our results indicate that policing effectiveness is simultaneously shaped by relatedness and group size, that is, an ecological factor. This may have major implications for testing policing across species of animals.

Interactions Between Third Parties and Consortship Partners in Tonkean Macaques (Macaca tonkeana)

Sexual competition is potentially disruptive for the cohesion of social groups because stress and conflicts can extend to other group members. The displays and interactions of sexual partners are liable to influence the behavior of group-mates, which may need to observe them to anticipate possible consequences. We studied 2 captive groups of Tonkean macaques (Macaca tonkeana) to test whether group-mates pay more attention to consort partners, modify their activities and social interactions, and exhibit signs of stress during periods of sexual consortships. We found that group-mates approached the top-ranking male more frequently and were more frequently oriented toward the consort pair at the time of consortship than at other times. Group-mates spent less time sleeping, and devoted less time to manipulating the environment and more time to monitoring during consortship. This indicates that consortships may incur costs in individuals not involved in sexual competition. However, Tonkean macaques did not exhibit any signs of increased stress during consortship periods, as their rates of scratching and yawning did not differ between consortship and nonconsortship periods. This study shows that not only direct competitors but also other individuals monitor the behavior of sexual partners. It is likely that group-mates obtain information this way about ongoing action, and take decisions accordingly.

Role of face‐to‐face and computer‐mediated communication time in the cohesion and performance of mixed‐mode groups

Although the rapid development of information technology has led to the increasing use of computer‐mediated communication (CMC), few studies have examined the relational aspect of mixed‐mode groups that use both face‐to‐face (FTF) communication and CMC. A field study comprising 42 student groups was conducted to assess the relationships among communication time, cohesion, and performance in mixed‐mode groups. The findings suggest that time spent in FTF communication significantly predicted group social cohesion, but time spent in CMC did not. In contrast, group task cohesion was predicted by time spent in CMC but not by time spent in FTF communication. Time spent in CMC was also a strong predictor of group task performance. These results suggest that FTF communication contributes to the social aspect of mixed‐mode groups and that CMC is beneficial to their task‐related aspect. The findings of mediation analyses showed a significant indirect effect among time spent in FTF communication, group social cohesion, and group contextual performance. In other words, time spent in FTF communication had a positive effect on group social cohesion, which in turn positively affected group contextual performance. However, no mediating effect was found among time spent in CMC, group task cohesion, and group task performance. Theoretical and practical implications of these findings are discussed.

The effects of fur rubbing on the social behavior of tufted capuchin monkeys

Fur rubbing has often been attributed as a social as well as a medicinal function in capuchin monkeys, yet to date there have been no studies investigating the effects of fur rubbing on subsequent group dynamics. Here, we report for the first time how social group cohesion is affected by fur rubbing in tufted capuchin monkeys. Fifteen captive capuchins were each observed six times for 45 min, three times following the provision of materials typically used for fur rubbing (onion) and three times following control food items (apple). When compared with the apple condition, monkeys significantly increased proximity to one another in the first 15 min of the onion condition, which is when most fur rubbing took place. Moreover, monkeys were more likely to spend time in groups when fur rubbing but less likely to spend time in groups when manipulating the onion in other ways. In subsequent periods monkeys were less likely to be in proximity to one another in the onion condition compared with the apple condition. Aggression between group members was elevated whereas affiliation was decreased throughout the onion condition. In short, capuchins spent more time further apart and engaged in more aggressive acts and shorter affiliative acts following fur-rubbing bouts. It is possible that these differences in behavior could be owing to differences in how the monkeys competed for and interacted with the items presented in each condition rather than due to fur rubbing as such. Alternatively, fur rubbing with pungent materials might interfere with olfactory cues used to regulate social interactions within a group and thereby cause increased levels of aggression.

Aquatic Exercise in Older Korean Women with Arthritis: Identifying Barriers to and Facilitators of Long-Term Adherence

The purpose of this study was to identify factors influencing long-term adherence to aquatic exercise in older women with arthritis. Participants (n = 72) completed an educational program on aquatic exercise and underwent follow up for 6 months. At follow-up, women who continued aquatic exercise (adherence group, n = 25) had significantly higher scores than women in the nonadherence group (n = 47) in exercise self-efficacy (p < 0.0001) and group cohesion based on social aspects (p = 0.009). Both groups reported experiencing similar barriers to exercise (rho = 0.78). The findings provide insights for the development of strategies to promote long-term adherence to this type of aquatic exercise. Specifically, the findings encourage the fostering of exercise self-efficacy and social group cohesion during participation in educational programs to increase long-term exercise adherence.

Introduction. Social intelligence: from brain to culture

Humans are perhaps the most social animals. Although some eusocial insects, herd mammals and seabirds live in colonies comprising millions of individuals, no other species lives in such a variety of social groups as Homo sapiens . We live in many different sized societies, from small, nomadic hunter

Mate fidelity and intra-lineage polygyny in greater horseshoe bats

Mating strategies that lead to increased kinship within socially cooperative groups may offer inclusive fitness benefits to individuals, but can also result in higher levels of inbreeding. Here we show in a sexually segregated bat species that females avoid this conflict through two mating behaviours. First, most females revisit and breed with specific, individual males across years, so that their single offspring born in different years are full siblings. Second, relatives in the maternal line, including mothers and daughters, share breeding partners (intra-lineage polygyny) more often than expected by chance. Although these behaviours increased levels of co-ancestry among colony members, there was no concomitant rise in inbreeding. We suggest that when females engage in mate fidelity and intra-lineage polygyny, kin ties among female roost mates will be strengthened, thereby potentially contributing to social group cohesiveness. Our findings reveal the hidden complexity that can underlie polygynous breeding, and highlight a new potential route by which female mate choice could influence social evolution.

FINE-SCALE GENETIC STRUCTURE AND SOCIAL ORGANIZATION IN FEMALE WHITE-TAILED DEER

Social behavior of white-tailed deer (Odocoileus virginianus) can have important management implications. The formation of matrilineal social groups among female deer has been documented and management strategies have been proposed based on this well-developed social structure. Using radiocollared (n = 17) and hunter or vehicle-killed (n = 21) does, we examined spatial and genetic structure in white-tailed deer on a 7,000-ha portion of the Savannah River Site in the upper Coastal Plain of South Carolina, USA. We used 14 microsatellite DNA loci to calculate pairwise relatedness among individual deer and to assign doe pairs to putative relationship categories. Linear distance and genetic relatedness were weakly correlated (r = −0.08, P = 0.058). Relationship categories differed in mean spatial distance, but only 60% of first-degree-related doe pairs (full sibling or mother–offspring pairs) and 38% of second-degree-related doe pairs (half sibling, grandmother–granddaughter pairs) were members of the same social group based on spatial association. Heavy hunting pressure in this population has created a young age structure among does, where the average age is < 2.5 years, and < 4% of does are > 4.5 years old. This—combined with potentially elevated dispersal among young does—could limit the formation of persistent, cohesive social groups. Our results question the universal applicability of recently proposed models of spatial and genetic structuring in white-tailed deer, particularly in areas with differing harvest histories.

Analysis of Spix's disc-winged bat association patterns and roosting home ranges reveal a novel social structure among bats

Spix's disc-winged bats, Thyroptera tricolor, roost in young, rolled leaves of Heliconia or Calathea plants. In this paper, we examined how the combination of high habitat availability, low occupancy rate and short longevity of those roosts may affect the pattern of interactions among individuals in the population. We regularly censused a 5.69-ha study area in northeastern Costa Rica and examined patterns of association using mark–recapture data. Thyroptera tricolor formed behaviourally cohesive social groups of mixed sex, ranging in size from four to 14 individuals. Approximately 85% of dyads maintained associations over time periods of up to 100 days, and 40% of dyads maintained longer-term associations of at least 420 days across sex classes. Individuals within social groups did not always roost together, but they shared a small common roosting home range, which averaged just 0.19 ha. Members of different social groups rarely associated, although limited associations between members of select social groups in one subunit were observed. However, roosting home ranges of adjacent social groups often overlapped (up to 39% of home ranges, and up to 92% of the area of the smaller home range), and home range centres were situated less than 100 m apart. Thus, social groups rarely interacted but overlapped in space. The features of this social system are unique among bats and mammals in general, and point to groupings based on kinship or cooperation.

The impact of adult mortality on household dissolution and migration in rural South Africa.

To investigate the effect of adult death on household dissolution and migration. Demographic surveillance of the population in a rural area of northern KwaZulu Natal, South Africa. Data on households resident in the surveillance area on 1 January 2000 were used to examine the effect of adult mortality and household risk factors on household dissolution and mobility between January 2000 and October 2002. Cox regression models were used to assess the risk of household dissolution and migration, controlling for multiple risk factors including causes of death, household composition and household assets. By October 2002, 238 households (2%) had dissolved and 874 (8%) migrated out of the area; 21% (2179) of all households had at least one adult death (18 years and older). Households where one or more adult members died during the follow-up period were four times more likely to dissolve, after controlling for household and community level risk factors [4.3; 95% confidence interval, (CI), 3.3-5.7]. The risk of dissolution was significantly higher in households with multiple deaths (2.3; 95% CI, 1.3-4.3). There were no significant differential risks associated with cause of death, age or sex of the deceased. Adult mortality in the household was not associated with migration. Poorer households, as measured by asset ownership, and households trying to cope with adult deaths are vulnerable to dissolution. The dramatic increase in adult mortality attributable to AIDS will increase the number of households that do not survive as a functional and cohesive social group.