This paper explores the insights that psychology can offer in shedding light on why hypermedia may work and thus in suggesting fruitful areas for future research. The philosophy underlying the paper is that research into the instructional efficacy of hypermedia should begin with a knowledge and appreciation of relevant psychological phenomena. Most discussions about hypertext tend to expound the virtues of hypertext and then go on to explain the coincidence of how this new technology happens to mirror the functioning of the brain. This paper takes the opposite approach, as it starts with an examination of theories and studies on how people learn, access, and use information and ideas, and only then moves on to consider the new technology that may mirror the way the brain works. Hypermedia has unique characteristics that point to relevant areas of learning research. An examination of the psychology and learning phenomena will inform the research and development of hypermedia. A brief explanation of the terms hypertext, hypermedia, interactive multimedia, interactive video, and multimedia is provided, followed by a discussion of various learning theories expounded in the literature of cognitive psychology. Cognitive flexibility theory, information processing theory, case based reasoning, generative learning, semantic networks, and dual coding theory are all discussed in reference to the new technology of hypermedia. (37 references) (Author/DB)