The goal of MultiWorld is to further integrate cognitive models with the real world. Traditionally, psychologists studying task switching have studied simple laboratory tasks in isolation. This approach has yielded decades of data, but little relevance to the sorts of tasks humans perform routinely. How are we able to perform multiple, complex tasks simultaneously? How do we decide to switch between two tasks? What is the mechanism enabling task switching? MultiWorld seeks to answer these questions by providing a framework for studying multitasking in complex environments. By running tasks and cognitive models on seperate computers, MultiWorld ensures that the dividing line between the two is made explicit. Thus the model sees only what its human counterpart sees.