Evidence for preferential processing for centrifugal and centripetal motions is somewhat mixed. On one hand, it has been reported that the primate visual system is more sensitive to centrifugal than to centripetal motion (Duffy & Wurtz,
1991a,
1991b; Graziano, Andersen, & Snowden,
1994; Maloney, Watson, & Clifford,
2013; Saito et al.,
1986; Tanaka, Fukada, & Saito,
1989; Xiao, Barborica, & Ferrera,
2006). This biased sensitivity for centrifugal over centripetal direction of motion is also consistent with an ecological point of view. The motion pattern created by forward movement consists of expanding optic flow (Crowell & Banks,
1993; Freeman, Harris, & Tyler,
1994), which also informs of a potential collision (Franconeri & Simons,
2003; Hassenstein & Hustert,
1999). On the other hand, a significant number of studies support preferential processing of centripetal over centrifugal direction of motion (Badcock & Khuu,
2001; Edwards & Badcock,
1993; Giaschi, Zwicker, Young, & Bjornson,
2007; Raymond,
1994; Shirai, Kanazawa, & Yamaguchi,
2006). In the current study, no preferential processing between centrifugal and centripetal motion directions was observed. However, because the stimuli used in the current study were translational (moving in one direction) motion patterns, they did not clearly represent either expanding or contracting perception, which is prominent in the optic-flow pattern.