This symposium presents four collaborative research projects conducted as part of LUCID, a unique cross-disciplinary graduate training program funded by the NSF’s National Research Traineeship mechanism. LUCID trains scientists from computational and behavioral disciplines to advance basic and applied research in domains where machines are used to instruct, predict, understand, respond to or learn from human users. Such human-machine interactions have a remarkably broad range of application—in public and private education across the lifespan, industry and information technology, public and private health management, social networking and communication, robotics and human-computer interaction, national security, public policy, and, of course, basic research into the nature of learning, cognition, and intelligent behavior.