“What does it mean, to see?” was the question that David Marr used to motivate his computation approach to understanding
Vision
(Marr, 1982). Marr's answer, building on Aristotle, was that “vision is the process of discovering from images what is present in the world, and where it is” (p. 3). Although we humans might have a preference for visual perception, we are endowed with other senses that provide us with a rich experience (Chapter 14, this volume). Therefore the broader question might be: What does it mean, to perceive? Although this might be seen as a philosophical question of sorts, it gets to the important issue of how we define perceptual experience scientifically so that we may study it. The importance of defining it is crucial for research applications: If we aim to restore a sense such as vision in blindness or hearing in deafness, what does it mean to see or to hear such that we will know when restoration has been successful? This chapter reviews the interaction between multisensory perception and interactive technological approaches to sensory rehabilitation.