1. Motor Development I. Age norms for important motor milestones II. The development of reaching A. Underlying skills of visually-guided reaching 1. Perceptual abilities 2. Motor skill 3. Perceptual-motor coordination B. Reaching in neonates C. Normative sequence of reaching D. Reaching for a moving object E. Is visually-guided reaching a myth? III. The development of locomotion A. Perceptual information in locomotion 1. Perceiving the properties of surfaces 2. Control of balance 3. Visually-guided locomotion B. A systems approach to development of walking 1. Component skills 2. Relation between skills

2. Age Norms For Important Motor Milestones Skill50%90% Lifts head 90° 2.2 3.2 when lying on stomach Rolls over2.84.7 Sits (propped up)2.94.2 Sits (no support)5.57.8 Stands holding on5.810.0 Walks holding on9.212.7 Stands alone11.513.9 Walks well12.114.3 Walks up steps17.022.0 Kicks ball forward20.024.0

3. Necessary Skills for Visually-Guided Reaching 1.Perceptual skills Object recognition Figure-ground separation 2.Motor skills Arm and hand coordination Fine-motor coordination and control 3.Visual-motor integration and coordination Visual guidance of the hand Timing of the grasp

4. The Normative Sequence of Reaching 1 – 2 Months Glance at objects when present Begin to fixate objects for 5-10 sec Arms not organized with vision 2 – 3 Months Isolation of components breaks down Focus on objects Beginning of prehensory behavior Raise hand towards object 3 – 4 Months Mutual grasping, 1 or 2 hands Sometimes turn torso towards object 4 – 5 Months Integrated looking and grasping “Top-level” reaching Good grasping of object

5. Reaching For A Moving Object The number of reaches at each speed and age, expressed as a proportion of the maximum number of possible reaches (3 per condition).

6. Type of Contact With a Moving Object The type of contact with the object. Proportion of total number of reaches for “grasp,” “touch,” and “miss.”

7. Is Visually-Guided Reaching a Myth Reaching in the light versus the dark – individual subjects

8. Infants’ Perceptions of the Traversability of Surfaces The Walkway Apparatus

9. The Visual Control of Posture The Moving Room Apparatus

10. Visually-Guided Locomotion in Toddlers

12. A Systems Approach to Locomotion