Triplet and Sibling Handwriting Study to Determine Degree of Individuality and Natural Variation

There have been no reports in the literature of handwriting studies that involved the comparisons of writings of triplets or comparisons of writings of multiple-birth siblings with their nonmultiple-birth siblings. The purpose of this small study, therefore, was to determine if the writing of one set of triplets and their nontriplet sibling could be distinguished and, if so, the degree of individuality in each subject’s writing. Unlike previous twin/sibling studies, normal or natural variation (intrawriter variation) is examined and contrasted with differences or dissimilarities (interwriter variation). The findings support the concept of natural variation in handwriting and two of the axioms of handwriting identification: (1) no two individuals write exactly alike, and (2) no one individual writes the same text exactly the same way twice.