The Palmar grasp is a reflex that all infants exhibit, until about 3 to 4 months of age. Stimulation on the baby's palm causes the child to automatically clamp down and grasp it. We've all seen this in action - placing a finger in a baby's palm causes the child grips it with surprising strength. This not only is this endearing to the parents (which encourages them to respond lovingly and caringly), but it prepares them to develop the reaching and grasping motor skill.