WORKING MEMORY DUAL-TASK PARADIGM DEMONSTRATES INDIVIDUAL DIFFERENCES IN COGNITIVE STYLE Application for Universal Design Based on Poor users' Cognitive Performances

Abstract

This research aimed to investigate individual differences in human cognitive style using working memory span task and dual-task paradigm. It would be important to know individual differences in performance on dual-task situations, because almost our everyday life is under dual or multi task situations: driving while talking with passenger, emailing while listening to music, or cooking while talking on the phone. We examined the character of “low”working memory span score subjects in detail, because they are more likely to have troubles than high working memory span score subjects when using some tool, devise, and interface in daily dual-task situations. The understanding their performances under dual-task situations can lead to better universal design. First, we divided low working memory span subjects into two groups based on their primary task (listening comprehension task) performances: good-low-span group (G-group) and poor-low-span group (P-group). Then, we compared performances under dual-task conditions between two groups. Secondary tasks were writing task and memory task. The results showed that primary task performances of G-group were decreased under either the writing task or the memory task, on the contrary that of P-group increased under both of dual-tasks. It is interesting to note that their performances were different under dual-task conditions even though their working memory span scores were not different. These results suggested that human cognitive style is highly diversified like G-group and P-group. Thus, they differently interact with tool, machine, or environment, etc. These findings can apply for engineering or designing of man-machine interface and for evaluating the concept of safety or usability.