What reflex causes hands to curl tightly around objects?

The palmar grasp reflex is the involuntary reaction where an infant's fingers curl tightly around an object placed in their hand, such as a finger or a toy. This reflex typically emerges in the first few months of life and plays a crucial role in early tactile exploration and bonding with caregivers. It reflects the infant's innate response to grasp, which is essential for developing hand-eye coordination and early motor skills.

In contrast, the Moro reflex is a startle reaction to sudden changes in the environment; the Babinski reflex involves the fanning of toes when the foot is stroked; and the stepping reflex is observed when an infant appears to make stepping motions when held upright. None of these reflexes are responsible for the specific curling action of the fingers around objects, which is why the palmar grasp reflex is the correct answer.