NSF PRFB 2022: A Bayesian framework for hierarchy: Do past experiences shape self-assessment of fighting ability?

Perkes, Ammon, Sacramento CA

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2022, Integrative Research Investigating the Rules of Life Governing Interactions Between Genomes, Environment and Phenotypes. The fellowship supports research and training of the fellow that will contribute to the area of Rules of Life in innovative ways. By combining video tracking with molecular approaches, the fellow will assess the behavioral and genetic drivers of social dominance. Specifically, the fellow will test the effect of past social interactions on an individual’s decisions in future dominance contests, and how these individual behaviors drive the formation of group hierarchy. These experiments will establish a new framework for analyzing and predicting social behavior, increasing our understanding of what determines the structure of social networks across animal species. The fellowship will also support the mentoring of students at both the high school and undergraduate level to establish opportunities for participation in science research and computational analysis. During social contests, prior winning often increases the likelihood of future victories via the winner-effect, mediated by a shift in individual aggression in subsequent contests. Bayesian updating provides an excellent framework to model the internal processes which drive these changes in behavior. The observed increase in aggression following a win suggests that animals are updating their own expectations of the probability of victory in future contests. Bayesian models allow us to predict changes at multiple scales: from the short-term effect of single contest events on an individual to the outcome of long-term, repeated interactions among larger groups. The fellow will test whether the winner-effect is consistent with Bayesian updating, by performing two experiments that test the model’s predictions: First, by staging repeated contests with controlled outcomes, the fellow will test whether unexpected events (e.g. a win against a larger fish) drive a greater contrast in gene expression and behavior than changes following expected outcomes; second, by performing long-term behavioral tracking in controlled social environments, the fellow will test whether the stability of the winner-effect is dependent on access to new information. This work will be conducted using the Amazon molly (Poecilia formosa), a naturally clonal species, limiting individual variation in biological replicates and providing increased statistical power for testing the mechanisms of social dominance. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.