The linear dependence between the response time and the concealment time in prediction of motion studies is confirmed. The parameters of the linear relationship could be considered as individual characteristics of the subjects. Our and other experimental results show that the parameters of the linear relationship could be manipulated selectively. Factors, which influence velocity perception and the subject's knowledge of the results, change mainly the slope value. Factors, changing the concealment time uncertainty, e. g. the moment of target presentation, affect the intercept value. It is supposed that the slope value reflects the subjective velocity scale and that the intercept value is related to the individual peculiarities of the subjects in organization and execution of a response in a definite moment.