Tracking moving targets of different predictabilities

Tracking experiments were conducted using the moving targets with different predictabilities. Human temporal information processing during the tracking was examined using physiological measurement. We used nonlinear methods of DFA, chaos theory and phase dynamics to analyzing the data. Our results on tracking errors in positions showed that the most unpredictable random target lead to most larger variance, whereas the target of most predictable sin wave and the one of chaotic motion with predictable in short term had lower variances. As for the tracking error with respect to instant phase, it found that target of sin wave gave arising a minimizing variance in compare with chaos and random. Further analysis by DFA showed that chaotic target resulted in significantly larger in scaling exponent for the instant phase differences between target and tracking, implying the most correlated process during the tracking. In addition, we found clearly changes in physiological status of subjects observed by ear plethysmogram during the tracking tasks. The largest Lyapunov exponent of the plethysmograms was found to be significant higher during tracking chaotic motion, showing a most active temporal information processing.