Higher education has long sought to balance its mass teaching model with personalized learning. The hope was that computers could provide the personalization at low cost through adaptive learning, but these efforts floundered due to the long hours required to populate adaptive learning systems with content and branching scenarios. Plus, it is much easier to program a computer to teach topics with objectively right answers (e.g., math and languages) than those that require students to describe abstract concepts (e.g., philosophy). As a result, adaptive learning systems never progressed much beyond souped-up, self-paced quizzing systems that were not really personalized in any way.