The goal of my research is to understand the structure of higher-level cognition with a particular focus on mathematical problem solving. This has led us to focus on what are called "unified theories of cognition." A unified theory is a cognitive architecture that can perform in detail a full range of cognitive tasks. Our theory is called ACT-R and takes the form of a computer simulation which is capable of performing and learning from the same tasks that subjects in our laboratories work at. ?We develop cognitive models for various tasks of interest constrained by the overall architecture
    Our current work has focused on analyzing brain imaging data to test cognitive models and to guide their development. In particular, we have been interested in parsing the time course of brain imaging data to get information about what is happening "under the hood" as people perform a complex task. This information is being used to help design instruction that will enable students extend their knowledge beyond the procedures that are taught.