Effect of Visual Feedback on the Static and Kinematic Characteristics of Handwriting

摘要

Research on visual feedback has not produced consistent results to show how visual feedback or the lack, thereof, influences individual handwriting characteristics. A two-pronged approach was designed to investigate the degree of this influence. For this purpose, samples of signatures as well as cursive and block text, written with and without visual feedback, were collected from 40 volunteers and imported into a PC via a pen tablet, using an electronic inking pen. The data was analyzed in a handwriting movement analysis software module specially designed for this research that was added to the software MovAlyzeR by Neuroscript LLC. Two forensic document examiners (FDEs) independently analyzed samples from the two groups (samples executed with normal visual feedback versus the group of samples executed without visual feedback). They found no fundamental differences between these two groups. Their analyses also demonstrated that a large number of similarities existed in the general design of the allographs (alternative forms of a letter or other grapheme) and in the pictorial aspects, regardless of the complexity of the samples. In the cursive and block handwriting, four main qualitative characteristics were linked to the absence of visual feedback: change of overall size, non-uniformity of left margins, change of baseline alignment, and inclusion of extra trajectories. The statistical analysis verified the above findings. The comparative analysis also suggests that gender, educational level (above high school) and handedness create an insignificant influence on the individual characteristics of writing produced with and without visual feedback. The only notable exception is the relationship between signature duration and educational level. The volunteers with a medium education level showed a significant increase in duration while signing their names without visual feedback in comparison to those with higher education levels. The combination of the above findings suggests that handwriting is not fundamentally influenced by visual feedback.