Kah Loon Ng

Systems approach to studying animal sociality: individual position versus group organization in dynamic social network models.

Social networks can be used to represent group structure as a network of interacting components, and also to quantify both the position of each individual and the global properties of a group. In a series of simulation experiments based on dynamic social networks, we test the prediction that social behaviors that help individuals reach prominence within their social group may conflict with their potential to benefit from their social environment. In addition to cases where individuals were able to benefit from improving both their personal relative importance and group organization, using only simple rules of social affiliation we were able to obtain results in which individuals would face a trade-off between these factors. While selection would favor (or work against) social behaviors that concordantly increase (or decrease, respectively) fitness at both individual and group level, when these factors conflict with each other the eventual selective pressure would depend on the relative returns individuals get from their social environment and their position within it. The presented results highlight the importance of a systems approach to studying animal sociality, in which the effects of social behaviors should be viewed not only through the benefits that those provide to individuals, but also in terms of how they affect broader social environment and how in turn this is reflected back on an individuals fitness.

Plasticity in Individual Choice in Social Network Evolution

Constant re-evaluation of social affiliation is known to cause populations of individuals with different predetermined affiliation preferences to diverge into different network structures. In this study, rather than assigning to each individual a fixed affiliation preference, held throughout the duration of the dynamic network evolution, individuals were allowed an initial “learning period” during which they compared their own relative success, using each of three strategies, at maximizing their social status under three different metrics. Based on the outcomes from this learning period, individuals then chose one particular strategy. The organizational success and stability of the resulting populations was seen to be higher than those of the populations of individuals whose behaviors were predetermined. This indicates that individual-level evaluation and strategy choice in social affiliation preferences can yield strong benefits to the organizational success of the population as a whole.

Graph theory : undergraduate mathematics

NUS represents National University of Singapore. NTU represents National Technological University, Singapore.