Following Navigation Instructions: Interdependent Spatial and Verbal Working Memory Processes

This study examined 3 theoretical issues involving working memory (WM) processes, movement dimensions, and serial positions. This examination was made in the context of investigating the ability to follow navigation instructions in a situation that mimicked communication between air traffic controllers and flight crews. Subjects heard navigation instructions describing movement within a 2-dimensional (2-D) computer display of a 3-D space consisting of four 4 x 4 stacked matrices. They repeated the instructions and then followed them by making movements on the computer screen. The 3-D space was shown from 2 different orientations (with the matrices stacked top to bottom or front to back). The effects of movement dimension depended on orientation; the dimension that was most difficult always involved movement outside the picture plane. The movement dimension effects also depended on the response requirements (mouse or keypad); they occurred only when a spatial WM representation was needed to make the movements (mouse). Likewise, serial position effects for the immediate oral repetition responses depended on the subsequent response requirements, providing a clear and strong demonstration that response requirements of the navigation task influence memory representations and memory performance, even for immediate verbatim recall completed before making the responses. More generally, these results support and elucidate the broader proposal that spatial and verbal WM processes are interdependent. The practical implications of these findings are discussed.