Sounds can alter the perceived direction of a moving visual object Department of Psychology, Graduate School of Arts and Letters, Tohoku University, Sendai, Miyagi, Japan,& Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan Wataru Teramoto Department of Psychology, Graduate School of Arts and Letters, Tohoku University, Sendai, Miyagi, Japan Souta Hidaka Neuroscience Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, Japan Yoichi Sugita Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan Shuichi Sakamoto Department of Psychology, Graduate School of Arts and Letters, Tohoku University, Sendai, Miyagi, Japan Jiro Gyoba Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan Yukio Iwaya Research Institute of Electrical Communication, Tohoku University, Sendai, Miyagi, Japan Yôiti Suzuki Auditory temporal or semantic information often modulates visual motion events. However, the effects of auditory spatial information on visual motion perception were reported to be absent or of smaller size at perceptual level. This could be caused by a superiority of vision over hearing in reliability of motion information. Here, we manipulated the retinal eccentricity of visual motion and challenged the previous findings. Visual apparent motion stimuli were presented in conjunction with a sound delivered alternately from two horizontally or vertically aligned loudspeakers; the direction of visual apparent motion was always perpendicular to the direction in which the sound alternated. We found that the perceived direction of visual motion could be consistent with the direction in which the sound alternated or lay between this direction and that of actual visual motion. The deviation of the perceived direction of motion from the actual direction was more likely to occur at larger retinal eccentricities. These findings suggest that the auditory and visual modalities can mutually influence one another in motion processing so that the brain obtains the best estimates of external events. Keywords: audiovisual interaction, motion perception, retinal eccentricity Citation: Teramoto, W., Hidaka, S., Sugita, Y., Sakamoto, S., Gyoba, J., Iwaya, Y., & Suzuki, Y. (2012). Sounds can alter the perceived direction of a moving visual object. Journal of Vision, 12(3):11, 1–12, http://www.journalofvision.org/content/12/3/11, doi:10.1167/12.3.11. Introduction Most objects and events in the external world generate concurrent inputs to several different sensory modalities. It has been assumed that each input is processed in the brain independently to some extent. However, we usually experience an integrated and unified percept of objects and events, suggesting that information from different sensory modalities is appropriately selected and bound together in the brain to represent a single object or event at several stages of perceptual processing. Indeed, recent studies on multisensory perception have revealed that different sensory modalities are closely related and mutually interplaying. In the domain of motion percep- tion, several studies have suggested that visual informa- tion influences auditory motion perception (e.g., Kitagawa & Ichihara, 2002; Soto-Faraco, Lyons, Gazzaniga, Spence, & Kingstone, 2002; Soto-Faraco, Spence, & Kingstone, 2003; Soto-Faraco, Spence, & Kingstone, 2004). These Journal of Vision (2012) 12(3):11, 1–12 http://www.journalofvision.org/content/12/3/11 1 doi: 10.1167/12.3.11 Received January 10, 2011; published March 12, 2012 ISSN 1534-7362 * ARVO