Palmar grasp reflex

[1] Placement of the object triggers a spinal reflex, resulting from stimulation of tendons in the palm, that gets transmitted through motor neurons in the median and ulnar sensory nerves.

[1][8][9][10] Biologists have found that the reflex is significantly more frequent in infants of fur carrying primate species.

It is theorized that the grasping reflex evolved as it is essential to survival in species, usually primates, where the young are carried in the fur.

The grasp reflex also allows young individuals to have more developed food manipulation and dexterity skills.

In other words, signals from the stimulation of tendons in the palm are being interrupted before they have a chance to make it to the spinal cord, resulting in a lack of the reflex.