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Concept: Social systems


Social systems are in a constant state of flux, with dynamics spanning from minute-by-minute changes to patterns present on the timescale of years. Accurate models of social dynamics are important for understanding the spreading of influence or diseases, formation of friendships, and the productivity of teams. Although there has been much progress on understanding complex networks over the past decade, little is known about the regularities governing the microdynamics of social networks. Here, we explore the dynamic social network of a densely-connected population of ∼1,000 individuals and their interactions in the network of real-world person-to-person proximity measured via Bluetooth, as well as their telecommunication networks, online social media contacts, geolocation, and demographic data. These high-resolution data allow us to observe social groups directly, rendering community detection unnecessary. Starting from 5-min time slices, we uncover dynamic social structures expressed on multiple timescales. On the hourly timescale, we find that gatherings are fluid, with members coming and going, but organized via a stable core of individuals. Each core represents a social context. Cores exhibit a pattern of recurring meetings across weeks and months, each with varying degrees of regularity. Taken together, these findings provide a powerful simplification of the social network, where cores represent fundamental structures expressed with strong temporal and spatial regularity. Using this framework, we explore the complex interplay between social and geospatial behavior, documenting how the formation of cores is preceded by coordination behavior in the communication networks and demonstrating that social behavior can be predicted with high precision.

Concepts: Sociology, Systems theory, Social psychology, Social network, Network theory, Network science, Complex network, Social systems


The present research tested whether incidental exposure to money affects people’s endorsement of social systems that legitimize social inequality. We found that subtle reminders of the concept of money, relative to nonmoney concepts, led participants to endorse more strongly the existing social system in the United States in general (Experiment 1) and free-market capitalism in particular (Experiment 4), to assert more strongly that victims deserve their fate (Experiment 2), and to believe more strongly that socially advantaged groups should dominate socially disadvantaged groups (Experiment 3). We further found that reminders of money increased preference for a free-market system of organ transplants that benefited the wealthy at the expense of the poor even though this was not the prevailing system (Experiment 5) and that this effect was moderated by participants' nationality. These results demonstrate how merely thinking about money can influence beliefs about the social order and the extent to which people deserve their station in life. (PsycINFO Database Record © 2013 APA, all rights reserved).

Concepts: Poverty, United States, Sociology, All rights reserved, Economic inequality, Capitalism, Free market, Social systems


Social dynamics are an important but poorly understood aspect of bat ecology. Herein we use a combination of graph theoretic and spatial approaches to describe the roost and social network characteristics and foraging associations of an Indiana bat (Myotis sodalis) maternity colony in an agricultural landscape in Ohio, USA. We tracked 46 bats to 50 roosts (423 total relocations) and collected 2,306 foraging locations for 40 bats during the summers of 2009 and 2010. We found the colony roosting network was highly centralized in both years and that roost and social networks differed significantly from random networks. Roost and social network structure also differed substantially between years. Social network structure appeared to be unrelated to segregation of roosts between age classes. For bats whose individual foraging ranges were calculated, many shared foraging space with at least one other bat. Compared across all possible bat dyads, 47% and 43% of the dyads showed more than expected overlap of foraging areas in 2009 and 2010 respectively. Colony roosting area differed between years, but the roosting area centroid shifted only 332 m. In contrast, whole colony foraging area use was similar between years. Random roost removal simulations suggest that Indiana bat colonies may be robust to loss of a limited number of roosts but may respond differently from year to year. Our study emphasizes the utility of graphic theoretic and spatial approaches for examining the sociality and roosting behavior of bats. Detailed knowledge of the relationships between social and spatial aspects of bat ecology could greatly increase conservation effectiveness by allowing more structured approaches to roost and habitat retention for tree-roosting, socially-aggregating bat species.

Concepts: Sociology, Bat, Social network, Network theory, Social structure, Indiana bat, Social systems, Mouse-eared bats


1.Animal social networks are descriptions of social structure which, aside from their intrinsic interest for understanding sociality, can have significant bearing on across many fields of biology. 2.Network analysis provides a flexible toolbox for testing a broad range of hypotheses, and for describing the social system of species or populations in a quantitative and comparable manner. However, it requires careful consideration of underlying assumptions, in particular differentiating real from observed networks and controlling for inherent biases that are common in social data. 3.We provide a practical guide for using this framework to analyse animal social systems and test hypotheses. First, we discuss key considerations when defining nodes and edges, and when designing methods for collecting data. We then discuss different approaches for inferring social networks from these data and displaying them. We follow with an overview of methods for quantifying properties of nodes and networks, as well as for testing hypotheses concerning network structure and network processes. Finally, we provide information about assessing the power and accuracy of an observed network. 4.Alongside this manuscript, we provide appendices containing background information on common programming routines and worked examples of how to perform network analysis using the R programming language. 5.We conclude by discussing some of the major current challenges in social network analysis and interesting future directions. In particular, we highlight the under-exploited potential of experimental manipulations on social networks to address research questions. This article is protected by copyright. All rights reserved.

Concepts: Scientific method, Sociology, Networks, Social network, Network theory, Complex network, Social structure, Social systems


Variation in extra-pair paternity (EPP) among individuals of the same population could result from stochastic demography or from individual differences in mating strategies. Although the adaptive value of EPP has been widely studied, much less is known about the characteristics of the social environment that drive the observed patterns of EPP. Here, we demonstrate how concepts and well-developed tools for the study of social behaviour (such as social network analysis) can enhance the study of extra-pair mating decisions (focussing in particular on avian mating systems). We present several hypotheses that describe how characteristics of the social environment in which individuals are embedded might influence the levels of EPP in a socially monogamous population. We use a multi-level social approach (Hinde, 1976) to achieve a detailed description of the social structure and social dynamics of individuals in a group. We propose that the pair-bond, the direct (local) social environment and the indirect (extended) social environment, can contribute in different ways to the variation observed in the patterns of EPP, at both the individual and the population level. A strength of this approach is that it integrates into the analysis (indirect) interactions with all potential mates in a population, thus extending the current framework to study extra-pair mating behaviour. We also encourage the application of social network methods such as temporal dynamic analysis to depict temporal changes in the patterns of interactions among individuals in a group, and to study how this affects mating behaviour. We argue that this new framework will contribute to a better understanding of the proximate mechanisms that drive variation in EPP within populations in socially monogamous species, and might ultimately provide insights into the evolution and maintenance of mating systems.

Concepts: Population, Ecology, Sociology, Monogamy, Social network, Network theory, Mating system, Social systems


1.The disease costs of sociality have largely been understood through the link between group size and transmission. However, infectious disease spread is driven primarily by the social organization of interactions in a group and not its size. 2.We used statistical models to review the social network organization of 47 species, including mammals, birds, reptiles, fish and insects by categorizing each species into one of three social systems, relatively solitary, gregarious and socially hierarchical. Additionally, using computational experiments of infection spread, we determined the disease costs of each social system. 3.We find that relatively solitary species have large variation in number of social partners, that socially hierarchical species are the least clustered in their interactions, and that social networks of gregarious species tend to be the most fragmented. However, these structural differences are primarily driven by weak connections, which suggests that different social systems have evolved unique strategies to organize weak ties. 4.Our synthetic disease experiments reveal that social network organization can mitigate the disease costs of group living for socially hierarchical species when the pathogen is highly transmissible. In contrast, highly transmissible pathogens cause frequent and prolonged epidemic outbreaks in gregarious species. 5.We evaluate the implications of network organization across social systems despite methodological challenges, and our findings offer new perspective on the debate about the disease costs of group living. Additionally, our study demonstrates the potential of meta-analytic methods in social network analysis to test ecological and evolutionary hypotheses on cooperation, group living, communication, and resilience to extrinsic pressures. This article is protected by copyright. All rights reserved.

Concepts: Infectious disease, Evolution, Structure, Sociology, Social network, Social, Mark Granovetter, Social systems


This article analyzes the trajectory of national health policy in Brazil from 1990 to 2016 and explores the policy’s contradictions and conditioning factors during the same period. Continuities and changes were seen in the policy’s context, process, and content in five distinct moments. The analysis of the policy’s conditioning factors showed that the Constitutional framework, institutional arrangements, and action by health sector stakeholders were central to the expansion of public programs and services, providing the material foundations and expanding the basis of support for the Brazilian Unified National Health System at the health sector level. However, historical and structural limitations, institutional legacies, and the dispute between projects for the sector have influenced national health policy. Interaction between these conditioning factors explains the policy’s contradictions during the period, for example with regard to health’s position in the national development model and social security system and the financing and public-private relations in health. Expansion of public services occurred simultaneously with the strengthening of private segments. Dynamic health markets that compete for resources from government and families, limit the possibility of consolidating a universal health system, and reiterate social stratification and inequalities in health.

Concepts: Health economics, Medicine, Universal health care, Sociology, Health care system, Health policy, Social security, Social systems


This study addressed the shaping of Mexico’s health system in recent years, with an analysis of the social determination conditioning the system’s current formulation, the consequences for the population’s living and working conditions, and the technical and legal reform measures that shaped the system’s transformation. The article then analyzes the survival of social security institutions and the introduction of an individual insurance model and its current implications and consequences. From the perspective of the right to health, the article compares the measures, resources, and interventions in both health care models and highlights the relevance of the social security system for Popular Insurance. The article concludes that the measures implemented to reform the Mexican health system have failed to achieve the intended results; on the contrary, they have led to a reduction in interventions, rising costs, and a decrease in the installed capacity and professional personnel for the system’s operation, thus falling far short of solving the problem, rather aggravating the inequities without solving the system’s structural contradictions. Health systems face new challenges, inevitably requiring that the analyses be situated in a broader framework rather than merely focusing on the functional, administrative, and financial operation of the systems in the respective countries.

Concepts: Health care, Health economics, Medicine, Healthcare, Insurance, Health care system, Social security, Social systems


This study applied a temporal social network analysis model to describe three affiliative social networks (allogrooming, sleep in contact, and triadic interaction) in a non-human primate species, Macaca sylvanus. Three main social mechanisms were examined to determine interactional patterns among group members, namely preferential attachment (i.e., highly connected individuals are more likely to form new connections), triadic closure (new connections occur via previous close connections), and homophily (individuals interact preferably with others with similar attributes). Preferential attachment was only observed for triadic interaction network. Triadic closure was significant in allogrooming and triadic interaction networks. Finally, gender homophily was seasonal for allogrooming and sleep in contact networks, and observed in each period for triadic interaction network. These individual-based behaviors are based on individual reactions, and their analysis can shed light on the formation of the affiliative networks determining ultimate coalition networks, and how these networks may evolve over time. A focus on individual behaviors is necessary for a global interactional approach to understanding social behavior rules and strategies. When combined, these social processes could make animal social networks more resilient, thus enabling them to face drastic environmental changes. This is the first study to pinpoint some of the processes underlying the formation of a social structure in a non-human primate species, and identify common mechanisms with humans. The approach used in this study provides an ideal tool for further research seeking to answer long-standing questions about social network dynamics.

Concepts: Human, Sociology, Primate, Networks, Social network, Network theory, Complex network, Social systems


The recent developments in the field of social networks shifted the focus from static to dynamical representations, calling for new methods for their analysis and modelling. Observations in real social systems identified two main mechanisms that play a primary role in networks' evolution and influence ongoing spreading processes: the strategies individuals adopt when selecting between new or old social ties, and the bursty nature of the social activity setting the pace of these choices. We introduce a time-varying network model accounting both for ties selection and burstiness and we analytically study its phase diagram. The interplay of the two effects is non trivial and, interestingly, the effects of burstiness might be suppressed in regimes where individuals exhibit a strong preference towards previously activated ties. The results are tested against numerical simulations and compared with two empirical datasets with very good agreement. Consequently, the framework provides a principled method to classify the temporal features of real networks, and thus yields new insights to elucidate the effects of social dynamics on spreading processes.

Concepts: Scientific method, Sociology, Systems theory, Dynamics, Statics, RealNetworks, Social systems, TiE