Effects of cognitive stress in handwriting movements in a pursuit loop-drawing task.

Abstract

The effects of concurrently presented visual traces of hand movements on timing, smoothness, and spatial accuracy were investigated during a loop-drawing tracking task. Thirty-five healthy young right-handed adults used a stylus on a digitizing tablet to track a left-to-right loop-drawing animation presented on a computer monitor. A dot target moved over a template of twelve connected cursive letter e’s, leaving a track as it drew over each loop in the series. Participants were instructed to draw along with the target to reproduce the shape of the loops at the tempo of the target. Participants performed sixteen trials in a 2 × 2 design, eight trials with their trace visible on the computer monitor and eight trials without a visible trace, half with a constant target rate and half with a variable rate change mid-trial. Spatial accuracy was greater when the participant trace was visible, as expected (p < .0001). An inverse relationship was found between drawing speed and spatial accuracy, consistent with the expectation that more spatial errors would occur at increased speeds. However, timing accuracy (p < .0001) and smoothness (p = .0026) decreased when the participant trace was visible. These results suggest that the visual trace of the participant tracking presented on the computer screen disrupted timing characteristics of perception-action coupling and increased the complexity of the task. Findings are discussed in the context of cognitive load.