A Model for Pointing at Targets with Different Clickable and Visual Widths and with Distractors

In this study, we extend Fitts' law to enable it to predict the movement time of pointing operations in interfaces, such as those in navigation bars whose items have different clickable and visual widths and intervals between a target and distractors. For this, we conduct two experiments to investigate the effects of distractors on pointing operations and how increasing the interval size changes user performance. We find that the movement time is significantly affected by the clickable width and intervals whereas it is only slightly affected by the visual width. Based on the results, we construct a time prediction model for considering the differences between clickable and visual widths and the intervals between a target and distractors. Our model shows a good fit for not only the data of our two experiments but also for those of three previous studies.