Influences of target discrimination capability on hand tracking

We performed a visually guided hand tracking experiment, where subjects using a mouse tracked an ellipsoidally moving target with frequency range from 0.1 to 1.8 Hz, and a fixation experiment, where subjects fixated their eyes during the target moving ellipsoidally. Performance on the natural ellipsoidal experiment showed that hand motion did not statistically precede the target in almost all frequency, while phase precedence was reported in a sinusoidal tracking (F. Ishida and Y. Sawada, 2001). On the other hand, hand motion in the fixation experiment preceded the target with frequency range 0.6 - 1.6 Hz, as well as in the sinusoidal. We assumed that these results could be explained from the viewpoint of target discrimination capability, because eye measurements revealed that mean retinal eccentricity during the ellipsoidal tracking task was smaller than the others. And we claim that the relative phase shifts to be positive, as the target discrimination capability is poor.