In 1891 Robinson1 drew attention to the curious ability of the newborn infant to suspend the weight of his body in midair by the strength of his own grip. Since that time the phylogenetic, ontogenetic and neurogenetic import of the phenomenon has received considerable attention. Three major questions which arise in connection with this behavior pattern are:
Why should the newborn baby be capable of a striking performance which for him has no recognized utility?
What are the essential or outstanding changes in this activity as the child develops from infancy to maturity?
In what way do developmental changes in a behavior of this order reflect maturational changes in the central nervous system?
The answer to the first question is still speculative. The theory suggested by Robinson1 in his original article on "Darwinism in the Nursery" has never been impressively challenged or refuted. The idea