Gredebäck, G., von Hofsten, C., Karlsson, J., & Aus, K. (2005) The development of two-dimensional tracking: A longitudinal study of circular pursuit. Experimental Brain Research, 163(2), 204-213.

We investigated 6- to 12-month-old infants’ ability to track an object moving on circular trajectories, using a longitudinal design. Consistent predictive gaze tracking was not found before 8 months of age. These results indicate that infants’ horizontal and vertical components of circular tracking are less mature than expected from previous studies of one-dimensional horizontal tracking. Vertical components are especially immature, particularly during high velocity tracking (􏰂20°/s). The results also suggest that horizontal and vertical tracking are mutually dependent during early development. Saccades were predictive (average lag >􏰃125 ms) from 6 months onwards.