An empirically-based theory is proposed that relates media's most essential modes of presentation--their symbol systems--to modes of cognitive representation and to the acquisition of knowledge. This book draws upon scholarship in such areas as the study of symbol systems, cognition, cognitive development, psycholinguistics, and mass…

Computer-based learning environments commonly comprise symbolic as well as static and dynamic pictorial representations, frequently combined with the possibility of modifying them interactively. While multiple, dynamic and interactive external representations have the potential to improve learning in various ways, they also place specific demands…

This paper focuses on issues of representation and interaction styles that are relevant considerations in the design and analysis of hypermedia learning environments. Analysis is supported by examples from the "HUGH" series of studies involving learners in reasoning about formal hypermedia representations. The representational issues include…