SPATIAL INVARIANCE OF HANDWRITING - A MATTER OF DEFINITION

Two aspects concerning the production of shapes in handwriting are dis tinguished in the present paper. The first aspect is indicated by the spatial variability of letters measured across replications. Spatial v ariability is assumed to reflect the basic spatial noise observed in e veryday writing. The second aspect deals with the geometric characteri stics of letter shapes, measured by the ratio of the vertical over the horizontal letter size (Y/X-ratio). The main question is whether the geometric characteristics and basic spatial noise originate from a com mon source. More specifically, we are interested in whether Y/X-ratio as well as spatial variability will alter across changed circumstances , or whether Y/X-ratio will alter without a change in spatial variabil ity. Subjects wrote the simple letter sequence lelele in conditions wi th and without vision under three scaling conditions requirements (sma ll, normal and large letter sizes). The main results were that geometr ic aspects of letters altered (Y/X-ratio) under no vision and under th e scaling requirement to write in a small format. In contrast, shapes were produced with unchanged spatial variability in all conditions of vision and scaling requirements. The results suggest that alterations of geometric aspects of letters across changed circumstances do not ne cessarily involve an increase in spatial variability.