As geographic information systems (GIS) technology matures and develops sophisticated decision support applications, there is an increasing need to optimise humancomputer interaction (HG) aspects. Although further advances in graphic interface design and operator training are required, the principal challenge is now in the ergonomics of shared cognitive responsibility between operator and computer system. Asound and comprehensive theoretical framework is required to understand and develop this relationship. Mental modelling provides an appropriate psychological paradigm wh ich may be applied through arranging appropriate levels of cognitive control, (modes of engagement), for GIS operations. The validation of such a theoretical model demands the use of appropriate research methodologies within a multidisciplinary HG in GIS research program. A substantial reference list is provided to ass ist research in this field.