Icon format on the in-vehicle HMI affects drivers’ cognitive performance

Although there have been many studies on icon preferences and search performances in the past, only a few principles, criteria, and guidelines may be applicable to the design of icons in a time- and safety-critical interaction (driving) context. This study combines a familiarity training task with an icon-semantic meaning recall task to explore the effects of icon format, concreteness and familiarity on drivers’ icon cognitive performance. Icons in 3 formats were created as experimental stimuli. Subsequently, 39 participants were divided into three groups, and each group was required to complete a familiarity training task with a specific icon format. After the participants were familiarised with the icons over two training sessions, their abilities to recall relevant semantic meanings when seeing icons were tested. The results indicated that participants responded more accurately and quickly to the icons in the graphic & keyword format than to the icons in the other two formats. However, the differences between different formats greatly decreased with an increase in familiarity. In addition, compared with concrete icons, abstract icons had an advantage in recognition speed, especially when the icons were unfamiliar. The findings in this study provide practical guidelines for the icon design of in-vehicle HMI.