His research explores the relationship between imaginative cognition and computation. He develops new forms of social media, gaming, computational narrative, and related computational media systems based in computer science, cognitive science, and digital media arts. The National Science Foundation has recognized Harrell with an NSF CAREER Award for his project "Computing for Advanced Identity Representation." He has worked as an interactive television producer and as a game designer. His recent book, Phantasmal Media: An Approach to Imagination, Computation, and Expression, is a Fall 2013 publication with the MIT Press.