Abstract: The concept of ephemeral adaptation was introduced to reduce visual search time in GUI menus, while preserving spatial consistency and minimizing distraction. We extend this concept to the visual search of app icons on smartphones, in order to speed up launching apps from a homescreen. We created ephemeral highlighting effects based on preattentive visual properties including size, orientation, color, opacity and blur. We then conducted informal design and evaluation cycles from which Twist (icon rotates back and forth) and Pulse (icon grows and shrinks) were the most promising effects. An experiment comparing these two effects to a control condition showed that these effects improve search time performance by 8--10% and Pulse is subjectively preferred.