Experimental studies of human-computer interaction : working memory and mental workload in complex cognition

Abstract: Complex cognition is readily described as cognitive tasks requiring the coordination of multiple steps of processing or tasks exceeding short term memory capacity. Similarly, mental workload may be described as the use and temporary expenditure of a finite amount of information processing capacity. In the current study, the mental workload of complex cognition was manipulated through variations in the mode of presentation (Study I) with the information being presented either printed on paper or displayed on a computer screen as well as through variations in page layout (Study II) with the information being presented, either using a page layout designed to fit the computer screen or on a long page of scroll type. In Study III, the short-term memory demands of the complex cognitive tasks themselves were explored. The principal findings of the three studies may be summarized by the following points: Consumption of information is more effective when information is presented on paper rather than displayed on a computer screen (Study I: Experiment 1). Similarly, Production of information is more effective when information is presented on paper (Study I: Experiment 2) rather than on a computer screen. Consumption of information generates less mental workload when the page layout is adapted to fit the computer screen (Study II: Experiments 1 & 2). Problem solving processes, including both Consumption and Production of information, may be described both in terms of their reliance on either ST-WM or LT-WM (Study III: Experiments 1, 2 & 3) and in terms of their reliance on specific 'slave systems' of the tripartite model (Study III: Experiments 1 & 3). Taken together, Studies I and II show that the presentation of information on screen, versus in printed form, exerts detrimental effects on human information processing and that some of those effects may be attributed to differences in the navigational properties of the two media. In addition, Study II demonstrated that an adaptation of the page layout of the presented material so that it fitted its intended media, mental workload may be alleviated. Finally, the results of Study III showed that, in order to understand the memory demands of complex cognition, it is necessary to include elements of both the ST- and LT-WM paradigm of Ericsson & Kintsch and the tripartite model of Baddeley & Hitch.