Examined in 4 experiments 2-year-olds' knowledge of solidity in search tasks. Found no evidence that 2-year-olds represented solidity and support constraints on trajectories of falling objects; two experiments included 2.5-year-olds who succeeded on search tasks. Explored implications of 2-year-olds' poor performance in light of very young…

Examined infants' ability to retrieve an object from atop a slightly larger object. Found that even 5-month-olds could retrieve objects close in size and fully contiguous with their bases when demands on reaching skill were reduced. Proposed that when they fail this task, it is because they lack the skill to reach the top object without…

Three experiments examined vision's role in infants' grasping of horizontally and vertically oriented rods. Found that infants differentially oriented their hand regardless of lighting and similar to control conditions where they could see rod and hand throughout reach. Findings suggest that infants may use current sight of object's orientation or…