Development of Handwriting Individuality: An Information-Theoretic Study

The task of writer identification is based on the assumption of individuality of handwriting. While previous studies of individuality have considered different statistical extremes: representative population of the United States and a population of twins, the present study takes a third approach-an analysis of handwriting over time, specifically children´s handwriting as they develop in early grades. Using extended handwriting samples of children in Grades 2-4, the commonly occurring word and written in cursive style as well as hand-print were extracted. The samples were assigned feature values by human questioned document examiners using a truthing-tool. The distribution of the characteristics were analyzed by first constructing probabilistic graphical models of the data. Information theoretic measures-entropy and relative entropy were computed using samples generated from the models. The measures are used to determine the range of variations in handwriting and the changes that take place between grades. Results from this early study indicates that handwriting develops with more conformity in grades 2 and 3, when they are first taught, and diverges as they grow older, between grades 3 and 4.