An Investigation of Target Acquisition with Visually Expanding Targets in Constant Motor-space
Philip J Brock
Department of Computer Science
University of Canterbury
Abstract
Target acquisition is a core part of modern computer use. Fitts’ law has frequently been proven to predict performance of target acquisition tasks; even with targets that change size as the cursor approaches. Research into expanding targets has focussed on targets that expand in both visual- and motor-space. We investigate whether a visual expansion with no change in motor-space offers any performance benefit. We investigate constant motor-space visual expansion in both abstract pointing tasks (based on the ISO9241–9 standard) and in a realistic deployment of the technique within fisheye menus. Our fisheye menu system eliminates the ‘hunting effect’ of target acquisition observed in Bederson’s initial proposal of fisheye menus, and in an evaluation we show that it allows faster selection times and is subjectively preferred to Bederson’s menus. We also show that visually expanding targets can improve selection times in target acquisition tasks, particularly with small targets.
