  For graphical user interface (UI) design, it is important to understand what
attracts visual attention. While previous work on saliency has focused on
desktop and web-based UIs, mobile app UIs differ from these in several
respects. We present findings from a controlled study with 30 participants and
193 mobile UIs. The results speak to a role of expectations in guiding where
users look at. Strong bias toward the top-left corner of the display, text, and
images was evident, while bottom-up features such as color or size affected
saliency less. Classic, parameter-free saliency models showed a weak fit with
the data, and data-driven models improved significantly when trained
specifically on this dataset (e.g., NSS rose from 0.66 to 0.84). We also
release the first annotated dataset for investigating visual saliency in mobile
UIs.
