Elizabeth Hobson (University of Tennessee, Knoxville)
Abstract. Dominance hierarchies are group-level properties that emerge from aggression among individuals. Although individuals can gain critical benefits from their position in a hierarchy, we do not understand how real-world hierarchies form, what signals and decision-rules individuals use to construct and maintain them, or the strategies individuals use to dynamically choose targets. New empirical work on monk parakeets, a highly social avian species, finds that awareness of rank emerges quickly and that individuals respond by focusing their aggression on targets close to them in rank. This strategic behavior appears to draw on knowledge associated with observation of network motifs, including chains of aggression. Follow-up work shows effects of dynamical strategy choice, where individuals condition their behavior on the target choices of others, leading to phenomena such as pile-ons and rank-based retreat. Results such as these, on the relationship between individual strategies and the group-level phenomena they create are an important part of understanding how socially complex groups come into being and how they develop over time.