ABSTRACT
The data obtained in the studies of the development of behavior have been examined by R. V. D. Campbell and A. A. Weech in order to determine whether or not they contain criteria which are capable of characterizing the individual child against a background of his peers. The techniques for manipulating the original data in order to determine these criteria, or measures of development, are fairly complicated. The data selected by Campbell and Weech for their study consisted of observations on forty children, including five sets of unisexual twins. The fact that methods led to identical results in describing the emergence of traits characterizing each individual child as age advanced, enhanced considerably the significance of the results. The success of any one criterion in identifying the individual child can be assessed in terms of the consistency exhibited by this criterion throughout the entire series of behavior activities.
