bullock’s doctorate work was performed at uc berkeley under the supervision of s.f. light, and focused on the organization of the nervous system (both anatomy and physiology) in acorn worms, generally considered a sister group to the chordates. this marked the beginning of his studies on simple nervous systems, which he used to explore the neural mechanisms that work together to produce an output in response to a stimulus, both at the physiological and behavioral level. during this time, the importance of comparative studies also became apparent to him. he believed that to fully understand how the brain and nervous system work, one must search for commonalities, and also for differences in nervous systems across different taxonomic levels.