ABSTRACT
When a child has to carry out a fairly complex action in order to solve a practical problem, his cognizance of the situa tion proceeds fairly systematically from the periphery to the center, that is, from the results of the action to its internal mechanism. If the action itself is simple but the subject has to use a device of perhaps greater complexity, he has to make a series of successive interpretations linked to the successes or failures of his practical intelligence,- from these interpreta tions he must extract the relevant law.
