A cognitive view of three selected online search facilities

This paper discusses the impact of three selected command language facilities on the man—system interface in relation to operational online information retrieval (IR). The concept of data and information is briefly considered in relation to the cognitive viewpoint and Brookes ‘fundamental equation of information science.’ A cognitive IR model is out‐lined, followed by a discussion of variously experienced searchers' knowledge structures. Recently developed online search facilities such as use of positional operators (free text operations), crossfile searching and term frequency analysis (zooming—as the ES A‐Quest command language calls it) are discussed in relation to the IR process. The cognitive view is applied as the means to describe and emphasise the retrieval possibilities and the state of knowledge involved in the interface processes.