ABSTRACT

The limited screen space in small touch screen devices imposes considerable usability challenges for human centered design. Thus, the tradeoff between object size and display size is crucial. In a previous study (Oehl, Sutter, and Ziefle, 2007), we found a strong effect of display size on pointing performance in a complex multidirectional serial pointing task. The very same task difficulty resulted in longer pointing times and a worse pointing accuracy on a smaller display compared to a bigger one. The central question of this current experimental study was, if this facilitating effect of display size is robust enough to appear and work even in a less complex and rather easy single pointing task. According to our previous experiment even for the less complex single pointing task, therc was a significant interaction between display size and increased task difficulty for movement time as well as for pointing errors. Results allow applied ergonomic guidelines for an optimized design of touch-based screen devices in terms of human centered design.