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Abstract:
A moving carrier behind a stationary envelope can cause a perceptual misplacement of this envelope in the direction of the motion (De Valois and De Valois, 1991 Vision Research 31 1619 - 1626). Yamagishi et al (2001 Proceedings of the Royal Society 268 973 - 977) showed that this effect can also be found in visuomotor localisation tasks. We created a motor task in which a vertically moving, curved path on a monitor had to be kept aligned with the centre of a Gabor (stationary Gaussian and moving carrier either horizontally or vertically). The seventeen participants controlled the horizontal position of the path with a joystick. According to previous findings, we expected that the motion of the carrier would elicit a misalignment between path and carrier, with a relative displacement in the direction of the motion of the carrier. We found such a bias. Speed, orientation, and eccentricity of the Gabor were manipulated. The bias was enhanced with increasing speed and the orientation determines the direction of the perceptual misplacement. In addition, large eccentricities created an asymmetry in the bias: the bias was greater for inward than outward motion. Implications of these findings for the general understanding of this bias are discussed.
