Kaori SEGAWA^1,2*, Hiroyasu UJIKE², Katsunori OKAJIMA¹, and Shinya SAIDA^2,3

¹Faculty of Environment and Information Sciences, Yokohama National University, Yokohama 240-8501, Japan ²National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8566, Japan ³Faculty of Human Sciences, Kanagawa University, Yokohama 221-8686, Japan

(Received October 27, 2011; Revised April 1, 2012; Accepted April 4, 2012)

We investigated the effects that the visual field has on the perception of heading speed. The stimulus was a radial flow pattern simulating a translational motion through a cylindrical tunnel. Observers evaluated the perception of heading speed by using a temporal two-alternative forced choice (2AFC) staircase method. In the first experiment, we manipulated the stimulus area by cutting the visual field along the longitudinal direction. The results showed that the perceived heading speed increases with the stimulus area. In the second experiment, we manipulated both the stimulus area and the eccentricity by cutting the visual field along the longitudinal direction. The results showed that the perception of heading speed increases when the stimulus occupies a large portion of the peripheral visual field. These findings suggest that the effect of eccentricity is a consequence of an incorrect translation of two-dimensional visual information into three-dimensional scaling.

Key words: heading speed, visual field, radial flow, stimulus area, eccentricity

^*E-mail address: segawa@ynu.ac.jp