The Development of Prospective Grasping Control Between 5 and 7 Months: A Longitudinal Study

By 7 months, infants, when reaching for an object, visually guide their grasp by preorienting their hands to match the object's orientation. Evidence at earlier ages, however, for prospective grasp control via anticipatory hand orientation is mixed. This study examined longitudinally the development of anticipatory hand orientation in 15 infants, seen every 3 weeks between 5 and 7.5 months. On each visit, infants were given 8 trials of reaching for an object oriented vertically and horizontally. Hand orientation at the first point of contact, prior to any tactile feedback, indexed infant prospective grasp. Between 5 and 7 months, infants showed evidence for qualitative transition in prospective control of grasp, supporting the contention that control of grasp shifts from being based on tactual feedback to being visually and therefore prospectively based. Implications for how prospective grasp emerges developmen-tally are discussed.