How is it that animal groups are often able to exhibit behaviors not possible at the individual level? The field of collective behavior aims to explain this emergence of group behavior, which is often visually remarkable: huge ungulate migrations, coordinated predator avoidance in birds, eusocial insect societies, and more. For my thesis, I am particularly interested in two themes within collective behavior: behavioral cascades and individual variation. I explore these by using a combination of theory and experiments with fish schools in the lab.

Behavioral cascades
How do behaviors spread through groups? Behaviors such as a fear response should be particularly contagious, but the context matters: animals must navigate a delicate cost-benefit tradeoff to avoid expending unnecessary resources on false alarms but being sensitive to true alarms. Understanding how this occurs in animal groups under varying levels of predation risk is a central aim of my PhD work.

Individual variation
Collective behavior models have long assumed homogeneous group membership, which has provided useful insights into group behavior such as the lack of top-down control or leadership required to create coordinated movement. While these models have formed excellent null expectations for group behavior, there is a risk in generalizing their results too strongly to real animal groups, which are innumerably heterogeneous in age, sex, body size, previous experience with the environment, and consistent individual differences (i.e. “animal personality”). This variation is likely to hold paramount importance for group behavior, but there is remarkably little known on its role in collective behavior. In my PhD, I aim to understand how variation in perception of risk may affect coordinated antipredator behavior.

(The photo above is of golden shiners tagged with elastomer dye. The tags glow under a UV light, allowing for individual identification.)