BVI Seminar: Diverted by dazzle: testing the ‘motion dazzle’ hypothesis.

Anna Hughes, University College London

Abstract: `Motion dazzle’ is the hypothesis that certain types of patterns, such as high contrast stripes and zigzags, can cause misperceptions in the speed and direction perception of moving targets. Motion dazzle is relevant to both ecological questions, including why striped patterning may have evolved in animals such as zebras, and also for camouflage design for human purposes. My work addresses the question of whether motion dazzle exists, and what mechanisms may underlie it if it does. I use an interdisciplinary approach, combining techniques from psychophysics and behavioural ecology in testing human subjects. I present data showing that targets with striped markings are among the hardest for humans to ‘capture’ in a touch screen task, but that these effects may depend upon factors such as target orientation and whether multiple targets are present. I also present psychophysical data that shows that subjects make small direction judgement errors that depend upon the orientation of the striped pattern on a target relative to the direction of motion, suggesting a possible mechanism for motion dazzle effects. Finally, I discuss future directions for my research, including a new project involving large scale data collection using citizen science methods.

Biography: Anna carried out her PhD at the University of Cambridge under the supervision of Dr David Tolhurst and Dr Martin Stevens, focusing on visual motion perception and how this is affected by camouflage patterns. She now works as a Teaching Fellow in Visual Perception at University College London.