Group Social Structure Research Articles

Long-term tracking of social structure in groups of rats

Rodents serve as an important model for examining both individual and collective behavior. Dominance within rodent social structures can determine access to critical resources, such as food and mating opportunities. Yet, many aspects of the intricate interplay between individual behaviors and the resulting group social hierarchy, especially its evolution over time, remain unexplored. In this study, we utilized an automated tracking system that continuously monitored groups of male rats for over 250 days to enable an in-depth analysis of individual behavior and the overarching group dynamic. We describe the evolution of social structures within a group and additionally investigate how past behaviors influence the emergence of new social hierarchies when group composition and experimental area changes. Notably, we find that conventional individual and pairwise tests exhibit a weak correlation with group behavior, highlighting their limited accuracy in predicting behavioral outcomes in a collective context. These results emphasize the context-dependence of social behavior as an emergent property of interactions within a group and highlight the need to measure and quantify social behavior in more naturalistic environments.

Group Dynamics and Social Structure of the Inia araguaiaensis in the Tocantins River, Brazilian Cerrado

Group Dynamics and Social Structure of the Inia araguaiaensis in the Tocantins River, Brazilian Cerrado

PSII-8 The effects of diet and finishing phase on the behavioral time budgets of feedlot cattle

Abstract Feedlot cattle undergo many transitions in diet, social group structure, and environment during the finishing period. Little is known about how their behavior may be altered by these transitions. The objective of our pilot project was to compare the behavior of younger feedlot cattle fed a low-concentrate diet to that of finishing cattle, and to create 24-h time budgets for activity and oral behaviors in these groups. Cattle [n = 20; body weight (BW) = 305 ± 21 kg, mean ± SD] were fed a low-concentrate feedlot diet (60:40, concentrate:forage; ST) and cattle (n = 20; BW = 522 ± 45 kg) received a finishing diet (90:10, concentrate:forage; FI) twice daily. Animals were separated by diet and housed in groups of 10. Trained observers recorded behaviors of each group by live instantaneous recording every 5 min for a continuous 48 h, resulting in 192 h of data collected. We predicted that ST cattle would spend more time eating and ruminating due to the higher forage diet. We also expected that FI animals would rest more and spend less time standing and walking as a result of being more familiar with the environment and their social group structure. We also quantified a wide range of oral behaviors including rumination, grooming and manipulation of non-feed items in the pen. Behaviors were summarized by 24-h period, animal, group, and diet, then averaged by animal, and then averaged again by group (n = 2/diet). Missing values accounted for 3% of the activity data and 11% of the oral behaviors. T-tests revealed that ST cattle ruminated more than FI (352 ± 3 vs. 304 ± 1 min/d, mean ± SE, P = 0.02), but differences between treatments were not detected for time spent eating (196 ± 15 vs. 131 ± 3 min/d), standing (584 ± 13 vs. 588 ± 29 min/d), walking (46 ± 10 vs. 35 ± 5 min/d), or lying (768 ± 16 vs. 772 ± 7 min/d; P ≥ 0.13). When fed the ST diet, cattle spent 5 ± 2 min/d grooming group mates, while FI cattle groomed others for 11 ± 1 min/d, although this was not analyzed statistically because it was rare. Similarly, there were numerical differences in the amount of time spent orally manipulating non-food items (8 ± 3 and 18 ± 1 min/d for ST and FI animals, respectively) that have not been previously described. These results suggest that behavioral differences might be more apparent with larger sample sizes, but with the present experimental design, the predictions were not supported. Nonetheless, these are the first behavioral observations of feedlot cattle and provide a comprehensive time budget of their activity, including a range of oral behaviors over a 48-h period.

Hormonal changes in northern white-cheeked gibbons (Nomascus leucogenys) after the death of a group member.

The small apes, gibbons and siamangs, are monogamous species with their social groups comprising of both parents and their offspring. Therefore, the loss of a member may elicit a stress response in the remaining members due to their strong bonds. Glucocorticoids (GCs) have been useful indicators of stress, but distinguishing between acute versus chronic stress may be limited when measuring these hormones alone. The adrenal hormone dehydroepiandrosterone-sulfate (DHEAS), a GC antagonist, has been implicated in the regulation of the stress response. Thus, the concomitant measurement of these hormones can help examine whether an event, such as the loss of a group member, elicited a stress response. In this brief report, we discuss the hormonal response of two zoo-housed northern white-cheeked gibbons (Nomascus leucogenys) (1 adolescent male and his mother) after the death of the adult male of the group. Baseline fecal samples were collected opportunistically from these two individuals 5months prior, and 3months following the death of their group member. A total of 25 samples were quantified for fecal GC metabolites (FGCMs) and DHEAS by enzyme immunoassay (EIA) to calculate the FGCMs:DHEAS ratio. Our results indicate an increase in FGCMs and FGCMs:DHEAS for the adolescent male, but not the adult female, following the death. Our findings suggest that the integration of FGCMs and DHEAS measurements can provide valuable information to interpret individual stress levels to the sudden change in the group's social structure.

Intraspecific variation in group structure arises due to environmentally-mediated directional dispersal in a cooperative breeder.

Many cooperatively breeding species live in groups with complex structure-large group sizes, low and variable kin structure, and multiple breeding pairs. Since these mixed-kin groups typically form because of immigration of unrelated individuals of both sexes in addition to limited offspring dispersal, differences in patterns of dispersal can generate variation in group structure, even within the same species or population. Here, we examine how environmentally mediated dispersal patterns influence variation in group structure in the plural breeding superb starling (Lamprotornis superbus), an avian cooperative breeder that inhabits a spatiotemporally variable savanna environment and forms mixed-kin groups with variable group sizes and more than one breeding pair per group. Using 4068 genome-wide polymorphic loci and fine-scale, remotely sensed ecological data from 22 groups sampled across a nearly 200 km2 environmental gradient in central Kenya, we find evidence of not only frequent and long-distance dispersal in both sexes (low isolation-by-distance and weak genetic structure), but also directional dispersal from small groups in lower quality habitat with low normalised difference vegetation index (NDVI) to large groups in higher quality habitat with high NDVI. Additionally, we find stronger genetic structure among groups in lower quality habitat, and higher genetic diversity and lower relatedness of groups in higher quality habitat. Previous work using long-term data from groups in the same population has shown that groups with lower relatedness are larger and have more breeding pairs. Long-distance, directional dispersal to maximise individual fitness can thus lead to smaller and simpler kin-based social groups in lower quality habitat, but larger and more complex mixed-kin groups in higher quality habitat. Such intraspecific, within-population variation in group structure, including variation in kin structure of social groups, could have profound implications for the relative importance of the evolutionary mechanisms (i.e. direct vs. indirect fitness benefits) underlying the formation of cooperative societies.

Social structure of Ukrainian society under the influence of full-scale war: conceptual and empirical research

This research is devoted to analyzing the changes that took place in the social-group structure of Ukrainian society during a year and a half of full-scale war. In order to realize this goal, firstly, the author considers the experience and conceptual foundations of the study of the relationship between war and social structure in Western and Ukrainian science and proposes a concept of the impact of total war on the social structure of a society that resists external aggression. Secondly, several preconditions of social-group dynamics were clarified — both destructive (due to which Ukraine quickly acquired characteristic features of the social structure during the martial law), and constructive (which contributed to the reproduction of pre-war social positions of citizens and a high degree of stability of the social system in general). Thirdly, the dynamics of the distribution of social groups and classes was analyzed every six months of the war based on various open official sources and the data of sociological surveys (in particular, the project “Social Inequality: Wartime Monitoring”, which was initiated by the researchers of the Department of Social Structures of the Institute of Sociology, NAS of Ukraine). The author proves that during the year and a half of the full-scale war, significant (both objective and subjective) socio-structural changes took place among the economically active population, though not linear ones, but with certain fluctuations (a rapid and significant transformation in the first six months and a movement towards gradual recovery over the next year). In particular, a significant (three-fold) increase in two groups (members of the armed forces and the unemployed), which were outside economic activity and accounted for almost a third of the working-age population in September 2022, and a quarter — a year later. The most noticeable changes among the employed population were the reduction in the number and restructuring of the working class and the class of owners, including the oligarchs. Fourthly, the author makes a forecast of further social-group dynamics under favorable and unfavorable developments: how will the quantitative distribution and internal structure of the main classes and groups change, as well as the social structure of the country in general.

Agonistic interactions and social behaviors in the Saharan Dorcas gazelle (Gazella dorcas neglecta): Using social network analysis to evaluate relationships and social structure in captive male groups.

Social interactions, including agonistic behavior, are very important for the management and welfare of individuals forming groups in captivity. One of the main concerns for the stability and durability of adult male groups is a noticeable level of intraspecific aggression. This study comprises a Social Network Analysis to illustrate social structure in different groups of captive Saharan Dorcas gazelles (Gazella dorcas neglecta). Our main objectives were to examine the relationship between agonistic, affiliative, and association networks and their reciprocity, assessing also whether the agonistic networks can conform to a linear dominance hierarchy. For these purposes, we recorded the behavior of 23 adult males organized in five herds, three composed only of Saharan Dorcas gazelle males and two mixed herds in which there were also Mhorr gazelle males (Nanger dama mohor). Observations were carried out during 295 h through scan sampling. We found no correlation between the affiliative and association networks in any group, although there was a significant correlation between the agonistic and association networks in mixed-species groups which was not present in single-species groups. Overall, there was no consistent reciprocity in either affiliative nor agonistic networks and none of the agonistic networks showed a linear structure. These results indicate that affiliative behavior in Saharan Dorcas gazelles offers distinctive and valuable information about the bonds between individuals, however, their dominance structure is far more complex than previously thought. As information provided by affiliative and proximity behaviors is different in this species, we suggest considering affiliative interactions to stablish affinity between individuals. Evaluating different social behaviors and not only agonistic interactions in later studies, is also recommended to develop a more accurately daily management in zoos that guarantee group stability and individuals' welfare, which will improve the conservation of captive populations.

Extending the social cohesion hypothesis: is group social structure associated with dispersal in yellow-bellied marmots (Marmota flaviventer)?

Abstract Dispersal is an important individual decision which may influence individual fitness as well as population viability. The social cohesion hypothesis posits more social individuals remain at home, which is supported by prior work across taxa. However, how the sociality and connectivity of the group an individual resides in—their group social structure—relates to dispersal decisions has not been explored. We extend the social cohesion hypothesis to predict individuals residing in more social groups would remain at home, and we quantified the affiliative and agonistic social network structure of female yellow-bellied marmots (Marmota flaviventer), a facultatively social ground-dwelling squirrel, where about half of all females disperse. Using mixed-effects models, we found no support for the hypothesis that affiliative group structure explained any variation in a marmot’s decision to disperse. We did find marmots in groups with less agonistic centralization (around one or few individuals) were less likely to disperse. The former finding may result from limited ability to perceive group structure whereas the latter may reflect individuals in less agonistically centralized groups are less likely to be reproductively suppressed. These results suggest individual dispersal decisions are more impacted by individual sociality and not that of their social group. Thus, the social cohesion hypothesis may not scale to the level of the group. Further work is required to determine whether dispersal decisions in obligately social species are influenced by group social structure.

The effect of social network structure on group anchoring bias

Decisions—whether made by individuals or groups—often involve estimating quantities, a process that is subject to anchoring bias (Tversky and Kahneman in Science 185: 1124–1131, 1974). Differences in susceptibility to anchoring bias between individuals and groups have been recently explored with the result that groups appear less biased than individuals (Meub and Proeger in Theor Decis 85:117–150, 2018). However, existing studies treat groups monolithically without taking into account their network structure—the pattern of relationships among members. The present paper investigates the effects of group social network structure on anchoring bias. Using a structured survey instrument, we gathered data on competence-based trust relationships among 264 students enrolled in a university degree program. An anchoring experiment was conducted in which some of the students made estimates as individuals, while others did so in groups of different structures. The findings provide initial evidence of differences in bias levels across variously structured groups as well as relative to individuals. Groups with highly centralized trust networks (where a single person owned everyone’s trust) showed more anchoring bias than dense groups (where everyone trusted everyone else) and sparse groups (where no one trusted any other member of the group) showed more bias than dense groups. In addition, despite previous research demonstrating groups are less susceptible than individuals to anchoring bias, this study shows a higher presence of bias in both our centralized groups and sparse groups when compared to individuals, suggesting that group structure might moderate the mitigating effect of groups on anchoring bias. The research has implications for organizational behavior and social network literature. Specifically, this study contributes to the debate on anchoring bias for group decisions by highlighting the significant role of social network structure. At the same time, it contributes to the literature on network structure and performance by providing initial evidence of how network structure affects anchoring bias susceptibility. Moreover, our study contributes to management practice by alerting managers to the dangers of centralized networks, suggesting that competence-based trust plays a vital role in the resistance to anchoring bias.

Group structure and individual relationships of sanctuary-living Grauer's gorillas (Gorilla beringei graueri).

The study of individual social relationships and group structure provides insights into a species' natural history and can inform management decisions for animals living in human care. The Gorilla Rehabilitation and Conservation Education (GRACE) center provides permanent sanctuary for a group of 14 Grauer's gorillas (Gorilla beringei graueri), a critically endangered and poorly studied subspecies of the genus gorilla, in the Democratic Republic of the Congo. We monitored the association patterns of the gorillas at GRACE over eight months and here describe their individual relationships and group structure via multiple social network statistics. The group was highly connected but associations between individuals were weak on average. Social network metrics describe that an adult female was the most gregarious and socially central individual within the group. In fact, adult females were the most gregarious and socially central on average. Group level association patterns were significantly correlated over the study period and across observation types, suggesting the group was socially stable during the eight month study period. The data collected in this study were done so by GRACE caregivers as part of their daily husbandry routine and provided important insights into this group's behavior, ultimately informing on their care, welfare and future release considerations. The methodological approaches implemented here are easily scalable to any primate sanctuary or care facility seeking to use data to inform husbandry and management procedures. Lastly, our study is the first social network analysis to be conducted on Grauer's gorillas and provides tentative insights into the behavior of this poorly studied subspecies. Though more research is needed to evaluate if the findings here are reflective of this subspecies' natural history or the idiosyncrasies of the group.

Social Network Evolution of Multiagent Groups in Task Allocation

The social network and group structure can improve the effectiveness of tasks and the management of multiagent systems (MASs). However, in complex task environments, the fixed network and social relation are not necessarily the optimal design. Therefore, agents should be able to adjust social relations in a distributed and self-organized manner to adapt to different task demands. To solve this problem, a hybrid social evolution mechanism based on Q-learning is proposed in this article. The evolution of social relations is realized from the perspective of individual, group, and global situations to improve the success rate and comprehensive effectiveness of task allocation in the system while reducing the communication cost during task execution. In addition, the hybrid evolution mechanism considers the balance of interests between the global and the individual, which can guarantee the rationality of task benefit distribution while improving the global effectiveness. The experiments show that compared with the single-form evolution method, the hybrid mechanism proposed in this article has more advantages in the success rate, communication cost, and comprehensive effectiveness of task allocation. Moreover, the rationality of benefit distribution is also improved, and a strong and harmonious social system is realized.

Study on the regional risk classification method for the prevention and control of emerging infectious diseases based on directed graph theory.

Emerging infectious diseases are a class of diseases that are spreading rapidly and are highly contagious. It seriously affects social stability and poses a significant threat to human health, requiring urgent measures to deal with them. Its outbreak will very easily lead to the large-scale spread of the virus, causing social problems such as work stoppages and traffic control, thereby causing social panic and psychological unrest, affecting human activities and social stability, and even endangering lives. It is essential to prevent and control the spread of infectious diseases effectively. We aim to propose an effective method to classify the risk level of a new epidemic region by using graph theory and risk classification methods to provide a theoretical reference for the comprehensive evaluation and determination of epidemic prevention and control, as well as risk level classification. Using the graph theory method, we first define the network structure of social groups and construct the risk transmission network of the new epidemic region. Then, combined with the risk classification method, the classification of high, medium, and low risk levels of the new epidemic region is discussed from two cases with common and looped graph nodes, respectively. Finally, the reasonableness of the classification method is verified by simulation data. The directed weighted scale-free network can better describe the transmission law of an epidemic. Moreover, the proposed method of classifying the risk level of a region by using the correlation function between two regions and the risk value of the regional nodes can effectively evaluate the risk level of different regions in the new epidemic region. The experiments show that the number of medium and high risk nodes shows no increasing trend. The number of high-risk regions is relatively small compared to medium-risk regions, and the number of low-risk regions is the largest. It is necessary to distinguish scientifically between the risk level of the epidemic area and the neighboring regions so that the constructed social network model of the epidemic region's spread risk can better describe the spread of the epidemic risk in the social network relations.

Group singing is globally dominant and associated with social context.

Music is an interactive technology associated with religious and communal activities and was suggested to have evolved as a participatory activity supporting social bonding. In post-industrial societies, however, music's communal role was eclipsed by its relatively passive consumption by audiences disconnected from performers. It was suggested that as societies became larger and more differentiated, music became less participatory and more focused on solo singing. Here, we consider the prevalence of group singing and its relationship to social organization through the analysis of two global song corpora: 5776 coded audio recordings from 1024 societies, and 4709 coded ethnographic texts from 60 societies. In both corpora, we find that group singing is more common than solo singing, and that it is more likely in some social contexts (e.g. religious rituals, dance) than in others (e.g. healing, infant care). In contrast, relationships between group singing and social structure (community size or social differentiation) were not consistent within or between corpora. While we cannot exclude the possibility of sampling bias leading to systematic under-sampling of solo singing, our results from two large global corpora of different data types provide support for the interactive nature of music and its complex relationship with sociality.

Linguistic landscape in film works and video games

Linguistic landscape studies can yield information about the society inhabiting the given area: the use and distribution of languages, but also social structure and hierarchy of linguistic groups. For these reason, the linguistic landscape can be used in artworks to convey information regarding the fictional reality to the recipient. This paper aims to analyse what functions the linguistic landscape can perform in film works and video games, and how certain aspects of fictional realities are portrayed through the intentional use of linguistic landscapes.

The (surprising) importance of males in a matrilineal society: behavioural insights from a topological knockout study

Social group structure often has consequences for individual fitness and ecological and evolutionary processes, but group structure is not fixed because of demographic processes: individuals die, disperse or are recruited into social groups. Thus, it is important to understand how demographic social roles and the loss of individuals with different roles modify group structure. We studied yellow-bellied marmots, Marmota flaviventer, and performed a series of statistical/topological knockouts on observed marmot social networks to investigate how the social roles of individuals from specific age–sex categories (adult/yearling, males/females) contribute to group social structure and to ask whether the loss of different roles has varying structural effects. We focused on five central aspects of overall social structure: density, the global clustering coefficient, reciprocity, global degree centrality and the coefficient of variation of strength. Somewhat surprisingly, given that marmots live in matrilines, our knockout results suggested that males played a key role in shaping networks: yearling males were a key cohesive element and adult males were central players in agonistic networks. Thus, social networks are dynamic and their structure is shaped in the interplay of demographic processes and individual social behaviour.

Behavioural defences against parasites across host social structures

Abstract Animals exhibit a variety of behavioural defences against socially transmitted parasites. These defences evolved to increase host fitness by avoiding, resisting or tolerating infection. Because they can occur in both infected individuals and their uninfected social partners, these defences often have important consequences for the social group. Here, we discuss the evolution and ecology of anti‐parasite behavioural defences across a taxonomically wide social spectrum, considering colonial groups, stable groups, transitional groups and solitary animals. We discuss avoidance, resistance and tolerance behaviours across these social group structures, identifying how social complexity, group composition and interdependent social relationships may contribute to the expression and evolution of behavioural strategies. Finally, we outline avenues for further investigation such as approaches to quantify group‐level responses, and the connection of the physiological and behavioural response to parasites in different social contexts. Read the free Plain Language Summary for this article on the Journal blog.

Emergent social structure is typically not associated with survival in a facultatively social mammal.

For social animals, group social structure has important consequences for disease and information spread. While prior studies showed individual connectedness within a group has fitness consequences, less is known about the fitness consequences of group social structure for the individuals who comprise the group. Using a long-term dataset on a wild population of facultatively social yellow-bellied marmots (Marmota flaviventer), we showed social structure had largely no relationship with survival, suggesting consequences of individual social phenotypes may not scale to the group social phenotype. An observed relationship for winter survival suggests a potentially contrasting direction of selection between the group and previous research on the individual level; less social individuals, but individuals in more social groups experience greater winter survival. This work provides valuable insights into evolutionary implications across social phenotypic scales.

Macaque progressions: passing order during single-file movements reflects the social structure of a wild stump-tailed macaque group.

Inferring the latent structures of social organisations is a central theme in animal ecology. Sophisticated theoretical frameworks underpin the study of various primate social systems. Single-file movements, defined as serially ordered patterns of animals, reflect intra-group social relationships and provide a key to understanding social structures. Here, we analysed automated camera-trapping data on the order of progression of single-file movements in a free-ranging group of stump-tailed macaques to estimate the social structure of the group. The sequence of single file movements showed some regularities, particularly for adult males. Social network analysis identified four community clusters (subgroups) corresponding to the social structures reported for these stumptailed macaques, i.e. males that had copulated more frequently with females were spatially clustered with females, but males that had copulated less frequently were spatially isolated from females. Our results suggest that stumptailed macaques move in regular, socially determined patterns that reflect the spatial positions of adult males and are related to the social organisation of the species.

Indirect genetic effects for social network structure in Drosophila melanogaster.

The position an individual holds in a social network is dependent on both its direct and indirect social interactions. Because social network position is dependent on the actions and interactions of conspecifics, it is likely that the genotypic composition of individuals within a social group impacts individuals' network positions. However, we know very little about whether social network positions have a genetic basis, and even less about how the genotypic makeup of a social group impacts network positions and structure. With ample evidence indicating that network positions influence various fitness metrics, studying how direct and indirect genetic effects shape network positions is crucial for furthering our understanding of how the social environment can respond to selection and evolve. Using replicate genotypes of Drosophila melanogaster fruit flies, we created social groups that varied in their genotypic makeup. Social groups were videoed, and networks were generated using motion-tracking software. We found that both an individual's own genotype and the genotypes of conspecifics in its social group affect its position within a social network. These findings provide an early example of how indirect genetic effects and social network theory can be linked, and shed new light on how quantitative genetic variation shapes the structure of social groups. This article is part of a discussion meeting issue 'Collective behaviour through time'.

Constitutive depletion of brain serotonin differentially affects rats’ social and cognitive abilities

Central serotonin appears a promising transdiagnostic marker of psychiatric disorders and a modulator of some of their key behavioral symptoms. In adult male Tph2 -/- rats, constitutively lacking central serotonin, we tested individual's cognitive, social and non-social abilities and characterized group's social organization under classical and ethological testing conditions. Using unsupervised machine learning, we identified the functions most dependent on serotonin. Although serotonin depletion did not affect cognitive performances in classical testing, in the home-cage it induced compulsive aggression and sexual behavior, hyperactive and hypervigilant stereotyped behavior, reduced self-care and exacerbated corticosterone levels. This profile recalled symptoms of impulse control and anxiety disorders. Serotonin appeared essential for behavioral adaptation to dynamic social environments. Our animal model challenges the essential role of serotonin in decision-making, flexibility, impulsivity, and risk-taking. These findings highlight the importance of studying everyday life functions within the dynamic social living environment to model complexity in animal models.