Timothy Vaughan Cottier

2.3.3.4 Flash-Drag Effect This flash-drag paradigm was based upon the original paradigm by (Whitney and Cavanagh 2000). Two sinusoidally modulated greyscale liner gratings (20.5 dva high and 3.6 dva wide) with a spatial frequency of 0.15 cycles per dva were presented 3.85 dva to the left and right of a red fixation cross subtending 0.5 dva. The two gratings drifted vertically in opposite directions with a speed of 26.7 dva/s for 2300 ms. The gratings direction of motion reversed after every trial.

Abstract Motion-Position Illusions (MPIs) involve the position of an object being misperceived in the context of motion (i.e. when the object contains motion, is surrounded by motion, or is moving). A popular MPI is the flash-lag effect, where a static object briefly presented in spatiotemporal alignment with a moving object, is perceived in a position behind the moving object. Recently, Cottier et al.