A Physicist’s View of Wiggling Worms and Fighting Fish

When we think of experimental physics, we often think of the most controlled experiments and precise machines, sometimes as big as a city, probing the largest and smallest measurable quantities. Experiments such as the LHC, LIGO, and the James Webb Space Telescope help us understand how fundamental forces in the universe affect everything from subatomic particles to clusters of galaxies. But what if a physicist wanted to understand something much more approachable in size but seemingly messier, and even alive, such as the behavior of an animal? How accurately can we measure what an animal does and what would those measurements teach us about an animal’s interactions with its environment, the ability of the brain to produce and control behaviors, and interactions between individuals? I will discuss efforts over the last decade to measure what animals do and how these experiments have begun to change our view of behavior and neuroscience. Moving past written descriptions of animal behavior of the greats such as Charles Darwin and Jane Goodall, we use modern techniques in machine learning and statistical physics to turn quantitative measurements of animal movements into a physics-based understanding of behavioral dynamics. I will touch on mind-reading in the nematode worm, optical behavioral control in the fruit fly, and fighting in zebrafish. Much of this modern renaissance in the Physics of Behavior was started ten years ago at a summer workshop at the Aspen Center for Physics.