Methods and Mechanisms of Motion Dazzle

‘Motion dazzle’ is a phenomenon where high contrast patterns are hypothesised to cause errors in speed and direction perception of targets that are in motion. Motion dazzle is relevant to both ecological questions, such as why striped patterning may have evolved in animals, and also for camouflage design for human purposes. I have used an interdisciplinary approach to address questions about motion dazzle in human subjects, combining techniques from psychophysics and behavioural ecology. I have focused on what aspects of a target are important in creating motion dazzle effects and what specific perceptual effects are seen, with a view to understanding the phenomenon at a mechanistic level. Using touch screen technology, I have replicated recent work that shows that targets with striped markings are relatively difficult for humans to capture, and have also shown that both overall luminance match of a target to the background, the distribution of ‘features’ on a target, and the orientation of target stripes relative to target motion are crucial in determining capture success. I have also made measurements of speed and direction judgements for targets with different patterning using psychophysical techniques. Speed judgments do not seem to be affected systematically by static striped patterning; however, subjects do show directional errors based on static stripe orientation relative to the direction of motion. Motion dazzle may therefore be an effective camouflage strategy caused by several different misperceptions, not all of which have been predicted previously