Use of speed cues in the detection of moving objects by moving observers

When an observer moves through an environment containing stationary and moving objects, he or she must be able to determine which objects are moving relative to the others in order to navigate successfully and avoid collisions. We investigated whether image speed can be used as a cue to detect a moving object in the scene. Our results show that image speed can be used to detect moving objects as long as the object is moving sufficiently faster or slower than it would if it were part of the stationary scene.

► We tested whether moving observers use image speed changes to detect moving objects. ► Observers detected objects moving 1.4 times faster than images of stationary objects. ► Observers detected objects moving 0.4 times slower than images of stationary objects. ► Depth variation in the scene did not change the threshold for object detection.