I investigate the cognitive mechanisms supporting adaptive control over behavior. To be adaptive over both evolutionary timescales and more momentary ones, and over both health and disease, these cognitive control mechanisms must balance constraints common to many resource-limited systems. I take inspiration from such systems, using formal models to refine hypotheses about how cognitive control may address these fundamental constraints. I then test these hypotheses with a convergent cognitive neuroscience approach. I test children and adults using physiological techniques like pupillometry and EEG, and cutting-edge technologies like fMRI and TMS, all building on a computational foundation in neural networks and Bayesian modeling. In my new role in Pfizer's Worldwide R&D department, I use knowledge from my research to assess the impact of novel compounds on cognition and the neural circuits supporting it.