Social Relationships and the Emergence of Social Networks

Alistair Sutcliffe,Robin Dunbar,Di Wang

doi:10.18564/jasss.2059

Alistair Sutcliffe, Robin Dunbar + Show 1 more

Open Access

https://doi.org/10.18564/jasss.2059

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Abstract

In complex social systems such as those of many mammals, including humans, groups (and hence ego-centric social networks) are commonly structured in discrete layers. We describe a computational model for the development of social relationships based on agents' strategies for social interaction that favour more less-intense, or fewer more-intense partners. A trust-related process controls the formation and decay of relationships as a function of interaction frequency, the history of interaction, and the agents' strategies. A good fit of the observed layers of human social networks was found across a range of model parameter settings. Social interaction strategies which favour interacting with existing strong ties or a time-variant strategy produced more observation-conformant results than strategies favouring more weak relationships. Strong-tie strategies spread in populations under a range of fitness conditions favouring wellbeing, whereas weak-tie strategies spread when fitness favours foraging for food. The implications for modelling the emergence of social relationships in complex structured social networks are discussed.

Highlights

Evolutionary theories of human social behaviour vary from cultural hypotheses which propose that social behaviour is a product of imitation, social learning and acquired norms of group behaviour (Boyd & Richerson 1988; Tooby & Cosimides 1989) to cognitive mechanisms grounded in plausible genetic origins
Theoretical models of social behaviour among unrelated individuals have demonstrated the evolution of cooperative behaviour and altruism (Nowak & Sigmund 1998, 2005; Roberts & Renwick 2003), where reciprocal rewards accruing from social relationships outweigh the costs of social interaction, thereby providing the incentive to invest in cooperation
Given that cooperation is reasonably well established as a foundation of social relationships in behavioural (Baumeister & Leary 1995; Brown & Brown 2009; Oswald et al 2004) and evolutionary (Boyd & Richerson 1988) terms, the question arises about what patterns of social relationships might emerge from cooperative behaviour and how these might relate to the observed patterns of structure found in real-life social networks

Summary

Introduction

1.1 Socio-psychological theories of social relationships range from relationship formation based on exchange and expectations of reciprocity (Brown & Brown 2009) to explanations of human attitudes towards groups and the relationship between individual and group in terms of social identity (Reicher et al 1995; Tajfel & Turner 1979), and from group socialisation (Moreland & Levine 1982) to wide-ranging frameworks encompassing success criteria for groups with models of their structure, and short-term evolution from formation to dissolution (Arrow et al 2000; Tuckman 1965). In our previous work (Sutcliffe & Wang 2012) we described a computer model of trust based on social interaction between agents and explored how different social predispositions such as favouring fewer strong, or more weak relationships effected the emergence of social structure and networks. Staged: in this dynamic strategy, the search bias is changed over time so the ego agent initially favours the few but progressively favours initiating proportionately more interactions with strangers and low-trust (weak-tie) partners This implements the behavioural predisposition manifest over an individual's lifetime, that strong ties are formed earlier in life, while weaker ties accumulate in later life and strong ties persist (Hays 1989). Decrement Trust by (MaxCR-CI × Trust) Increment Defect by 1 End-If Decrement Trust by W {4} End-Do End-While

Two fitness functions were defined

Trust model parameters were taken from the optimal SBM fit simulation

Discussion and Conclusions

Findings

Limitations and Future