Social Science Computer Review

Volume 32, No. 3

June 2014


Table of Contents


Symposium Issue on Social Simulation


Guest Editors: Flaminio Squazzoni & Bruce Edmonds


Symposium issue on social simulation: An introduction /  Flaminio Squazzoni & Bruce Edmonds


Social simulation in the social sciences: An overview / Flaminio Squazzoni, Wander Jager, and Bruce Edmonds

Abstract: This article provides an overview of the social simulation approach to the study of social phenomena. We focus especially on the relevance of heterogeneity of social behavior and dynamics and the complex interplay of agent behavior and social structure. The article identifies the peculiarities and the explanatory achievements of this approach and then discusses its prospects and challenges. Special attention is given to: (i) how micro-level behavioral detail can be used to understand social patterns and dynamics; (ii) the importance of the meso-level of social networks, and (iii) the two way, process linkages between micro and macro aspects as a fundamental source of social uncertainty and unpredictability.


On the coevolution of stereotype, culture and social relationships: An agent0based model  / Kenneth Joseph, Geoffrey Morgan, Michael K. Martin, & Kathleen M. Carley

Abstract: The theory of Constructuralism describes how shared knowledge, representative of cultural forms, develops between individuals through social interaction.  Constructuralism argues that through interaction and individual learning, the social network (who interacts with whom) and the knowledge network (who knows what) co-evolve. In the present work, we extend the theory of Constructuralism and implement this extension in an agent-based model. Our work focuses on the theory’s inability to describe how people form and utilize stereotypes of higher order social structures, in particular observable social groups and society as a whole.  In our agent-based model, we formalize this theoretical extension by creating agents that construct, adapt and utilize social stereotypes of individuals, social groups and society.  We then use this model to carry out a virtual experiment which explores how ethnocentric stereotypes and the underlying distribution of culture in an artificial society interact to produce varying levels of social relationships across social groups.   In general, we find that neither stereotypes nor the form of underlying cultural structures alone are sufficient to explain the extent of social relationships across social groups. Rather, we provide evidence that shared culture, social relations and group stereotypes all intermingle to produce macro-social structure.


Escalation of ethno-nationalist radicalisation: Simulation of the effectiveness of nationalist ideologies / Martin Neumann

Abstract: This paper describes an agent-based simulation model of ethno-nationalist radicalization between political actors and their constituencies based upon evidence from the former Yugoslavia. The central mechanism is the recursive feedback between political and cultural dynamics, focusing on processes prior to the outbreak of actual violence. The results offer theoretical insights by revealing mechanisms which lead to escalation. These can be found within politics as well as among the population: conflicting ethnically homogeneous regions, opposing radicalization forces fuel an es-calation spiral. These processes are driven by political influences. Challenging the theory that di-versity breeds conflict, this suggests that multi-ethnic regions are more capable of withstanding political pressures. However, they are vulnerable to imported violence, driven by the local popula-tion. This finding is tested with a different model of the same events, in which different implemented mechanisms generate results, in line with the diversity-breeds-conflict theory. A comparative discussion demonstrates how simulation is sensitive to theoretical pre-dispositions.


The norm signaling effects of group punishment: Combining agent-based simulation and laboratory experiments / Daniel Villatoro, Giulia Andrighetto, Jordi Brandts, Luis Gustavo Nardin, Jordi Sabater-Mir, & Rosaria Conte

Abstract: Punishment plays a crucial role in favouring and maintaining social order. Recent studies emphasize the effect of the norm signaling function of punishment. However, very little attention has been paid so far to the potential of group punishment. We claim that when inflicted by an entire group, the recipient of punishment views it as expressing norms. The experiments performed in this work provide evidence that humans are motivated not only by material incentives that punishment imposes, but also by normative information that it conveys. The same material incentive has a different effect on the individuals’ future compliance depending on the way it is implemented, having a stronger effect when it also conveys normative information. We put forward the hypothesis that by inflicting equal material incentives, group punishment is more effective in enhancing compliance than uncoordinated punishment, because it takes advantage of the norm-signaling function of punishment. In support of our hypothesis, we present cross-methodological data, i.e., data obtained through agent-based simulation and laboratory experiments with human subjects. The combination of these two methods allows us to provide an explanation for the proximate mechanisms generating the cooperative behaviour observed in the laboratory experiment.


Impact of homophily on diffusion dynamics over social networks / Mustafa Yavas & Gönenç Yücel

Abstract: The purpose of this study is to analyze the impact of homophily on diffusion over social networks. An agent-based simulation model is developed to serve as the experimental ground for this analysis. Diffusion dynamics of a non-sticky innovation is investigated by varying homophily levels in the social network depicted in the model as the primary control variable. First of all, the results show that homophily is self-reinforcing. Secondly, starting from a non-homophilious network, early increases in the level of homophily have a positive effect on the extent of diffusion whereas further increases have a negative impact. Finally, several local minima and maxima are observed in the relation between the homophily level and the extent of diffusion. Our analysis focuses on node properties such as connectedness and average degrees in order to explain the observed regular relationship between homophily and diffusion. We argue that (i) homophily increases the connectedness of different status groups separately, and (ii) increasing levels of homophily decreases the marginal importance of a single homophilious tie by increasing the sources of valuable information. Future research involves investigating the co-evolution of social behavior and networks by allowing the adopted innovation to lead to value homophily, exploration of different diffusion initiation types, and different adoption heuristics.


A model of spatially constrained social network dynamics / Elisabeth Zu Erbach-Schoenberg, Seth Bullock, & Sally C. Brailsford

Abstract: Social networks characterise the set of relationships amongst a population of social agents. As such, their structure both constrains and is constrained by social processes such as partnership formation and the spread of information, opinions and behaviour. Models of these coevolutionary network dynamics exist, but they are generally limited to specific interaction types such as games on networks or opinion dynamics. Here we present a dynamic model of social network formation and maintenance that exhibits the characteristic features of real-world social networks such as community structure, high clustering, positive degree assortativity and short characteristic path length. While these macro-structural network properties are stable, the network micro-structure undergoes continuous change at the level of relationships between individuals. Notably, the edges are weighted, allowing for gradual change in relationship strength in contrast to more abrupt mechanisms, such as rewiring, used in other models.  We show how the structural features that characterise social networks can arise as the result of constraints placed on the interactions between individuals. Here we explore the relationship between structural properties and four idealised constraints placed on social interactions: space, affinity, time, and history. We show that spatial embedding and the subsequent constraints on possible interactions are crucial in this model for the emergence of the structures characterising social networks.


Agent-based modeling of information transmission in early historic trading / Christopher Frantz, Martin Purvis, & Mariusz Nowostawski

Abstract: This work introduces a multi-agent model for informal communication about cheating merchants among investing Genoese traders in the 12th century. The model builds on previous, game theory focused work of Avner Greif and extends it by enabling communication between Genoese traders. A trust-based cooperation model is tested across different network topologies as well as two different communication modes, a) a reactive one representing Genoese trader interrelations, and b) a more proactive one that is based on accounts on the relationships among a North African traders collective, known as the medieval Maghribian Traders. The simulation shows that even for high levels of initial trust among Genoese, their mode of communication would not have sufficed to collectively identify cheating merchants and prevent them from future transactions. The results obtained from the tested network topologies are further discussed in the light of literature accounts of both historical societies.


Social interaction in hunter-gatherer societies. Simulating the consequences of cooperation and social aggregation / Juan Barcelo, Florencia Del Castillo, Ricardo Del Olmo, Laura Mameli, Francisco José Miguel Quesada, David Poza, & Xavier Vila

Abstract: This paper describes the design and operation of an ABM that represents aspects of hunter-gatherer subsistence, technology, and cultural identity. The agents (representing families or households) in the model interact in a world that has a seasonally-variable resource density. Agents must collect resources every step, either independently (by “gathering”) or with cooperation from neighboring agents (“hunting”). Several parameters affect cooperation: understanding these effects is one of the main foci of the paper. Another focus is understanding the effects of cooperation in terms of cultural diversity/homogeneity. Some input parameters are historically and ethnographically calibrated, and the results are contrasted, with ongoing archaeological research of Patagonian hunter-gatherers (from 7000 BC or even earlier to 19th. century). Specific research questions include: How do processes of convergence and divergence occur between groups of hunter-gatherers over the long-term? How could the autonomous local interactions of heterogeneous bounded rational agents generate this kind of regularity? What role outside influence plays on the formation of ethnic identities? Our aim is to integrate the state-of-the-art knowledge from different social sciences and technological developments into a fruitful approach to develop socio-historical studies