Two experiments were conducted to determine whether the conjoint retention hypothesis (Kulhavy, Lee, & Caterino, 1985) is a viable explanation for the facilitative advantages of adjunct displays by examining whether encoding and retrieval processes involve using the visuospatial sketchpad component of working memory (Baddeley, 1992). Experiment 1 investigated encoding effects on working memory performance by having college students view (a) a verbal or spatial representation, (b) an adjunct display, and then be tested on (c) recognition of the representation, and (d) comprehension of the adjunct display. In Experiment 2, (a) and (b), and (c) and (d) were reversed to examine retrieval effects. Results indicated that spatial memory was worse than verbal memory when processing graphic organizers, concept maps, and outlines, but not text; and when retrieving information after processing graphic organizers and concept maps, but not outlines and text. Thus, the conjoint retention hypothesis explains the facilitative advantages of spatial, but not linear adjunct displays.