Abstract:  Next time you are on a train with nothing better to do, stare at the scenery rushing past outside the window. When you stop at the next station, the platform may appear to be slowly drifting backwards. This compelling effect, also known as the 'waterfall illusion', is the result of adaptation of the visual system to high image velocities. Motion adaptation also changes our perception of the speed of moving patterns, and increases our sensitivity to changes in image velocity. Remarkably similar effects have been observed in the visual systems of many other animals, from butterflies to wallabies.

Flying insects have arguably the best-understood visual system of any animal. I will describe experiments from flies that provide insights into mechanisms of motion detection and adaptation. My research combines intracellular recordings from motion-sensitive cells with computer modelling of elements thought to underlie biological motion detection.

Resume: Rob Harris received his B.Sc. in Psychology from the University of Sussex and his Ph.D from the University of Cambridge in 2000. He is presently a Wellcome Trust International Visiting Research Fellow at Princeton University, USA, studying retinal physiology and eye movements.