A defi ning feature of the fi eld of instructional design (ID) is a commitment to practice. In contrast with educational psychology and the learning sciences, instructional design theories are more explicit in guiding practitioners through the process of creating courses and integrating media. This is in keeping with its origins in the mid-twentieth century, when behavioral psychologists used programmed instruction as a means for implementing scientifi c advances (Reiser, 2001a ). By determining which instructional strategies worked for particular learning objectives, the goal was a comprehensive science of instruction that could also serve as a prescriptive guide for practice (Lumsdaine & Glaser, 1960 ; also Reigeluth, 1983). Practice in those days referred to an opportunity for students to apply a rule or procedure to a case (as in Rule-Example-Practice sequences).