Does the production of letter strokes in handwriting benefit from vision?

In earlier studies the involvement of vision in handwriting was suggested by the finding that the production of a letter sequence in a condition without vision took more time and resulted in larger letter trajectories. The present study raises the question whether vision has an impact on the production of the individual up- and downstrokes constituting the letters. More specifically, the aim is to examine whether vision is employed either during the completion of a movement, or concurrent with the entire course of a stroke movement. Adult writers produced the letter sequence lelele under a no-vision and a vision condition, the latter serving as a base-line condition. It was found that movement time and trajectory size of acceleration and deceleration phases of a stroke movement increased under no vision, the magnitude of which depended on letter type. Letter e, with a smaller size and more frequently used in Dutch writing than letter l, was less affected by the no-vision condition. Although, close examination of downstrokes produced in later letter positions of the sequence revealed that the acceleration as compared to the deceleration phase took proportionally less time, the general finding was that increments in time and size proved to be equally distributed across entire stroke movements.