Problems of Forensic Sciences 2011 Vol. 86 (LXXXVI) 93-102
The development of left-handed writing features of a right-handed person who has undertaken training in writing with his left hand
Tomasz Dziedzic
Institute of Forensic Research, Kraków, Poland
Streszczenie
In a forensic handwriting expert’s casework, an attempt to disguise one’s handwriting by executing it with the hand other than the usual one may be encountered. Such a disguise might concern either disputed writing (e.g. a signature written with the intention of disclaiming it) or reference writings (e.g. requested samples). The effectiveness of detection may depend both on the intensity of the suspect’s training and the expert’s competence. Therefore, it is useful to study and describe the process of developing the features of handwriting executed by a fluent writer who begins to write with an unaccustomed hand. The author, being a right-handed person, trained his left hand in handwriting for the purpose of the present research. He executed 200 samples in the period 2007–2010, each of which consists of 10–20 lines of text and the same number of signatures. In the collected material, the process of development of selected features in consecutive samples was examined. This allowed determination of how fast the particular features change due to the improvement of motor ability of the subject’s left hand and how soon they reach a table state, if indeed they do. The research showed that features which are rooted in the human psychological sphere stabilized in the first 5–10 samples and did not undergo any further changes. The features which depend on the motor skills of the hand carried on developing until the last sample. The signatures show a high level of automation and circa the 150th sample (i.e. after executing about 2000 signatures) gained a natural appearance, free from any motor disorder.
Słowa kluczowe
Handwriting; Left hand; Unaccustomed hand; Lateralization; Handwriting training; Development of handwriting features.