Visual conspicuity of a moving dot, horizontal line segment or vertical line segment

The effect of varying the retinal eccentricity of a moving target on its conspicuity were explored for targets whose shape, orientation, size and luminance were the same as the stationary background elements. The target was a dot, horizontal line segment, or vertical line segment. The main results were: (1) conspicuity increased monotically as a function of velocity for all of the cases. (2) The rate of the increase of conspicuity slowed down at around a velocity between 0.6 and 0.8 deg/sec (break in slope). (3) For individual subjects, the size of conspicuity area for a dot was not so different from that for a horizontal line segment, but it was very different from that for a vertical line segment. (4) The position of the break in slope shifted upward or downward from one another but not laterally. The results indicate that the conspicuity was not due to the sum of the outputs in movingness analyzing system (MAS, Transient-channel) and displacement analyzing system (DAS, Sustained-channel), but due to one of them according to velocity of the moving element.