Considerations on efficient touch interfaces - How display size influences the performance in an applied pointing task

The limited screen space in small technical devices imposes considerable usability challenges. On the one hand objects displayed on small screens should be big enough to be hit successfully, but also small enough to house several objects on the screen at the same time. However, findings up to now show that single pointing is more effective in a large display compared to a smaller display. In the present experiment this was also confirmed for an applied multidirectional serial pointing task. Especially in more difficult tasks, results point at a shift of the speed-accuracy tradeoff. In large displays a fast and comparably accurate execution is chosen in contrast to a very inaccurate and time-consuming style in small displays. From an ergonomie point of view the outcomes recommend an optimized balance of task difficulty and display size in small screen devices.