Latencies and kinematics reflect graphic production rules

Abstract

Graphic production rules govern starting points, directions, and stroke order in copying and drawing. Recently, the authors proposed a working model and a quantitative specification of such rules for the copying of a well-defined set of geometrical patterns (Thomassen and Tibosch 1991). The present paper presents a reaction-time and kinematic analysis of the movements involved in reproducing these patterns. It shows that rule-governed copying is clearly reflected by the latency and kenematic measures. Movement sequences corresponding to graphic production rules are less variable, are generally preceded by shorter reaction times and are produced more rapidly due to shorter pen-up trajectories. An interpretation of those findings in terms of a hierarchical model of movement preparation shows that the rule-bound selection of a stroking sequence occurs at a relatively high level of preparation. As predicted, ‘anchoring’ constitutes a special rule, reflecting its advance planning by longer latencies and its precision features by higher accuracy and lower velocities of the involved movements. The latter results are also in agreement with the hierarchical model to the extent that, following the higher-level selection of an anchoring solution, the actual execution of anchored strokes is dealt with at a lower level in the hierarchy.