title: The development of two-dimensional tracking: a longitudinal study of circular pursuit.
abstract: 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 (approximately 20 degrees /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.
authors.affiliation: Department of Psychology, Uppsala University, Box 1225, 75142, Uppsala, Sweden. gustaf.gredeback@psyk.uu.se
authors.forename: Gustaf
authors.initials: G
authors.lastname: Gredebäck
authors.forename: Claes
authors.initials: C
authors.lastname: von Hofsten
authors.forename: Jessika
authors.initials: J
authors.lastname: Karlsson
authors.forename: Kati
authors.initials: K
authors.lastname: Aus
mesh_terms: D000375:Aging / Q000502:physiology; D001921:Brain / Q000254:growth & development*; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology*; D006801:Humans; D007223:Infant; D007858:Learning / Q000502:physiology; D008297:Male; D009039:Motion Perception / Q000502:physiology*; D009434:Neural Pathways / Q000254:growth & development; D009949:Orientation / Q000502:physiology*; D010775:Photic Stimulation; D011698:Pursuit, Smooth / Q000502:physiology*; D012438:Saccades / Q000502:physiology; D013028:Space Perception / Q000502:physiology*