THE GRASPING REFLEX IN THE NEW-BORN MONKEY

Abstract

In 1891, Robinson¹ found that a new-born human infant is able to support its own weight when holding on to a horizontal rod. He tested sixty infants, and found that all except two could hang for at least ten seconds, and one infant hung for two minutes and thirty-five seconds. Robinson believed that this ability is due to the presence of a primitive grasping response seen in monkeys and apes, by means of which the new-born monkeys hold on to the hair on the under surface of the mother's body. It occurred to me that it would be of interest to know more about the reflex in new-born monkeys, particularly as to its strength in comparison with the reflex of the new-born human infant and its persistence after birth. Hitherto there have been no opportunities for making such observations. It is only in recent times that it has been