Learning through experience: an emergent connectionist account of letter production behaviour

In handwriting the drawing or copying of an individual letter involves a process of linearising whereby the form of the letter is broken down into a temporal sequence of strokes for production. In experienced writers, letters are produced consistently using the same production methods that are economic in terms of movement. This regularity permits a rule-based description of such production processes, which can be used in the teaching of handwriting skills. In this paper, the outstanding question from rule-based descriptions as to how consistent and stable letter production behaviour emerges as a product of practice and experience is addressed though the implementation of a connectionist model of sequential letter production. This model: (1) examines the emergence of letter production behaviour, namely-the linearising process, (2) explores how letters may be internally represented across both spatial and temporal dimensions, and (3) investigates the impact of learning certain letter production methods when generalising to produce novel letterforms. In conclusion, the connectionist model offers an emergent account of letter production behaviour, which addresses the co-representation of spatial and temporal dimensions of letters, and the impact of learning experiences upon behaviour. 3 1. Introduction Handwriting involves the structured sequencing of movements in order to produce a letter or a string of letters. The process whereby a complete static letterform is broken down into a temporal sequence of strokes for production is known as 1991). This fundamental initial stage in the handwriting process is relatively autonomous, and is likely to be subject to a variety of influences such as culture and handedness, in combination with the level of skill and practice b). Generally, the sequence in which individual letter strokes are produced is strongly influenced by the direction in which the writing will be read (Alston and Taylor 1990). For writing that is produced from left to right (as in Western cultures), the sequence of strokes usually commences at the leftmost point of the letter, progressing through neighbouring strokes, although in some cases letters are produced starting with the topmost point of the first vertical line of the letter. In the experienced writer, letter production is fluent and economical (Thomassen, Meulenbroek, and Tibosh 1991). Letters are produced in a manner that is both biomechanically and cognitively efficient, and is typified by a production trajectory that uses the minimum number of strokes, with ideally the movement trajectory being as continuous (as few pen-up movements and positional changes) …