The motion-induced shift in the perceived location of a grating also shifts its aftereffect Anna A. Kosovicheva # $ Department of Psychology, University of California, Berkeley, Berkeley, CA, USA Gerrit W. Maus # $ Department of Psychology, University of California, Berkeley, Berkeley, CA, USA Stuart Anstis # $ Department of Psychology, University of California, San Diego, San Diego, CA, USA Patrick Cavanagh # $ Laboratoire Psychologie de la Perception, Universit ´ e Paris Descartes, Paris, France Peter U. Tse # $ Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH, USA David Whitney # $ Department of Psychology, University of California, Berkeley, Berkeley, CA, USA Motion can bias the perceived location of a stationary stimulus (Whitney & Cavanagh, 2000), but whether this occurs at a high level of representation or at early, retinotopic stages of visual processing remains an open question. As coding of orientation emerges early in visual processing, we tested whether motion could influence the spatial location at which orientation adaptation is seen. Specifically, we examined whether the tilt aftereffect (TAE) depends on the perceived or the retinal location of the adapting stimulus, or both. We used the flash-drag effect (FDE) to produce a shift in the perceived position of the adaptor away from its retinal location. Subjects viewed a patterned disk that oscillated clockwise and counterclockwise while adapting to a small disk containing a tilted linear grating that was flashed briefly at the moment of the rotation reversals. The FDE biased the perceived location of the grating in the direction of the disk’s motion immediately following the flash, allowing dissociation between the retinal and perceived location of the adaptor. Brief test gratings were subsequently presented at one of three locations—the retinal location of the adaptor, its perceived location, or an equidistant control location (antiperceived location). Measurements of the TAE at each location demonstrated that the TAE was strongest at the retinal location, and was larger at the perceived compared to the antiperceived location. This indicates a skew in the spatial tuning of the TAE consistent with the FDE. Together, our findings suggest that motion can bias the location of low-level adaptation. Keywords: motion processing, flash-drag effect, tilt-aftereffect, orientation adaptation Citation: Kosovicheva, A. A., Maus, G. W., Anstis, S., Cavanagh, P., Tse, P. U., & Whitney, D. (2012). The motion-induced shift in the perceived location of a grating also shifts its aftereffect. Journal of Vision, 12(8):7, 1–14, http:// www.journalofvision.org/content/12/8/7, doi: 10.1167/12.8.7. Introduction One of the most fundamental tasks for our visual system is to localize objects within the visual field. Object localization can be influenced by a number of factors independent of retinal position. For example, eye movements (Cai, Pouget, Schlag-Rey, & Schlag, 1997; Ross, Morrone, & Burr, 1997), spatial attention (e.g., Suzuki & Cavanagh, 1997), frames of reference (Roelofs, 1935), and adaptation (Whitaker, McGraw, & Levi, 1997) have all been shown to produce illusory shifts in perceived position. Notably, a substantial body of literature has shown that object motion can systematically bias perceived location (e.g., De Valois & De Valois, 1991; Ramachandran & Anstis, 1990; Whitney & Cavanagh, 2000). For instance, when a brief stationary flash is presented in alignment with a moving object, the flash appears to lag behind the moving object (Nijhawan, 1994). The motion of an object can Journal of Vision (2012) 12(8):7, 1–14 1 http://www.journalofvision.org/content/12/8/7 doi: 10.1167/12.8.7 ISSN 1534-7362 Ó 2012 ARVO Received March 02, 2012; published August 15, 2012