Y. Tomino, a Japanese famous animator, suggested that leftward motions would be perceived faster than rightward motions. A psychologist Yoshida (2006) found that people held different activity impression to the leftward and rightward motion. The present research aimed at directly catching the directional difference in the speed perception using the method of paired comparisons. Adding to the horizontal motions, we also examined the directional differences in the vertical dimension in which the gravity might influence on the speed perception. The participants were divided into two groups; 31 students were requested to compare the uniform motions and 38 students were requested to compare the accelerated motions. We provided three different speed (accelerated) motions which were moderately difficult to discriminate to each other. The participants in the uniform motion condition showed consistent tendencies; they perceived the leftward motion to be faster than the rightward motion and upward motion faster than the downward motion. In the accelerated motion condition, however, our participants didn’t show any consistent tendency.
method of paired comparisons