My research has focused on the relationship between perception, cognition, and action control. It is commonly understood that we gather information from the environment and use it to intelligently guide our behaviors. My work has suggested that the control flows in the opposite direction as well; when we choose to engage in a particular type of behavior, our perceptual and cognitive systems change, in fundamental ways, to better mediate those actions. As the response demands of a task behavior are altered, even when the overt informational demands of the task remain the same, adult experimental participants become selectively sensitive to certain sources of information and remarkably insensitive to others. Related work with infants suggests that when they engage in active reaching behaviors, rather than simpler looking behaviors, a separate system of knowledge is recruited to interpret the surrounding world. Such results indicate a need for theories of mental and neural processing that are able to account for rapid, fundamental shifts in the structure of human cognition and perception.