Working memory theory, as conceived and innovated by Alan Baddeley, is concerned with the active manipulation of information in mind, as distinct from a passive intuiting of relationships via associationism or a more rote activation of information in short-term memory theories. Interest in understanding the processes involved in the "active manipulation", and identifying the nature and form of the "information", has been the impetus for working memory becoming perhaps THE dominant theory and paradigm of Western cognitive psychology in the last quarter century.
For a review of working memory theory, see: Baddeley, A. (2012). Working memory: theories, models, and controversies. Annual review of psychology, 63, 1-29.