This chapter traces the history and how it evolved into contemporary mouse-tracking research that features a diversity of theoretical perspectives seeking to answer novel questions across a range of topics, rather than focused squarely on architectural debates. In the early days of mouse-tracking, the method was deployed mainly for architectural debates centered on adjudicating between discrete-stage based, modular explanations of cognitive processing versus a more continuous and integrated view of the mind. With mouse-tracking serving as a continuous output of response competition, one could observe graded partial activation of competing representations, or the extent of such conflicting activation within a single decision. Mouse-tracking is especially suited for measuring the real-time integration of multiple dimensions or attributes during a decision process. Neuroscientific inquiries into cognition have begun to include mouse-tracking to answers outside the domain of social cognition, for example, in the domain of intertemporal choice.