Audio or tactile feedback: which modality when?

When designing interfaces for mobile devices it is import-ant to take into account the variety of contexts of use. We present a study that examines how changing noise and dis-turbance in the environment affects user performance in a touchscreen typing task with the interface being presented through visual only, visual and tactile, or visual and audio feedback. The aim of the study is to show at what exact environmental levels audio or tactile feedback become inef-fective. The results show significant decreases in perform-ance for audio feedback at levels of 94dB and above as well as decreases in performance for tactile feedback at vibration levels of 9.18g/s. These results suggest that at these levels, feedback should be presented by a different modality. These findings will allow designers to take advantage of sensor enabled mobile devices to adapt the provided feed-back to the user's current context.