As a platform for research in perception and cognition, the PSL Tools support a variety of experimental designs, including factorial designs and expanded factorial designs (see Massaro, 1998), to investigate the manner in which perceivers combine information from different knowledge sources (e.g., speech sounds and facial movements). The PSL Tools also allow researchers to design and conduct experiments in which people interact with computers to perform interesting and useful tasks. In addition, the PSL Tools provide an ideal tool for use in laboratory courses (e.g., perception, psycholinguistics) to teach students to design and conduct research. Learning to apply the scientific method promotes critical thinking, and offers students new ways to conceptualize problems and investigate the world.