A simple saliency model predicts a number of motion popout phenomena

Visual search for a moving target among stationary distracters is more efficient than searching for a stationary target among moving distracters, and searching for a fast target among slow distracters is more efficient than vice versa. This indicates that the ease of search for a target with a particular motion is not determined simply by the difference between target and distracter velocities. We suggest a simple model for predicting ease of search for a unique motion, based upon a quantitative measure of target saliency. Essentially, search will be easier the more the target motion deviates from the general pattern of velocities in the scene. Our model predicts a number of well-known motion search phenomena, and suggests that one control for target saliency as well as target discriminability when drawing conclusions about visual system mechanisms from search experiments. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.