The Role of Visual Information Quantity in Fine Motor Performance

Abstract

Background/objectives: Fine motor movements are essential for daily activities, such as handwriting, and rely heavily on visual information to enhance motor complexity and minimize errors. Tracing tasks provide an ecological method for studying these movements and investigating sensorimotor processes. To date, our understanding of the influence of different quantities of visual information on fine motor control remains incomplete. Our study examined how variations in the amount of visual feedback affect motor performance during handwriting tasks using a graphic pen tablet projecting on a monitor.

Methods: Thirty-seven right-handed young adults (20 to 35 years) performed dot-to-dot triangle tracing tasks under nine experimental conditions with varying quantities of visual cues. The conditions and triangle shape rotations were randomized to avoid motor training or learning effects. Motor performance metrics, including absolute error, time of execution, speed, smoothness, and pressure, were analyzed.

Results: As visual information increased, absolute error (from 6.64 mm to 2.82 mm), speed (from 99.28 mm/s to 57.19 mm/s), and smoothness (from 4.17 mm²/s⁶ to 0.80 mm²/s⁶) decreased, while time of execution increased (from 12.68 s to 20.85 s), reflecting a trade-off between accuracy and speed. Pressure remained constant across conditions (from 70.35 a.u. to 74.39). Spearman correlation analysis demonstrated a moderate to strong correlation between absolute error and time of execution across conditions. The Friedman test showed significant effects of experimental conditions on all motor performance metrics except for pressure, with Kendall's W values indicating a moderate to strong effect size.

Conclusion: These findings deepen our understanding of sensorimotor integration processes and could potentially have implications for optimizing motor skills acquisition and training and developing effective rehabilitation strategies.

Keywords: fine motor behavior; fine motor movements; graphic pen tablet; motor performance; sensorimotor integration; tracing task; visual feedback.

Figure 1

Experimental setup. The upper gray rectangles represent the conditions displayed to the participant. The conditions not represented between 9 points and full shape are summarized inside square brackets. Numbers ‘1’, ‘2’, ‘3’ were positioned around each vertex of the triangle to indicate the order in which the sides should be traced. Other informations are in the text. Below is the experimental setup. In the figure, a stylized depiction shows the seated subject drawing on a tablet while looking at the monitor.

Figure 2

Boxplots representing the distribution of absolute error (A) and time of execution (B) across the experimental conditions. The dotted lines indicate the trendlines, obtained by connecting the means of each condition. (C) Comparison between the trendlines of absolute error (green) and time of execution (orange). The shaded areas around both trendlines represent the standard error of the mean. The values above the trendlines indicate the Spearman correlation coefficient R. The ‘*’ indicates that the Spearman correlation test is statistically significant, while ‘ns’ indicates no significant correlation.

Figure 3

Boxplots representing the distribution of speed (A), smoothness (B), and pressure (C) across the experimental conditions. Each color gradation of the circles inside the boxplots corresponds to a different experimental condition. The dotted lines indicate the trendlines, obtained by connecting the means of each condition.

Figure 4

Triangular heatmap of pairwise comparisons using Durbin–Conover post hoc analysis with Bonferroni correction (p-values = 0.0056) of absolute error (A), time of execution (B), speed (C), and smoothness (D). Dark green indicates p-values < 0.001, light green indicates p-values between 0.001 and 0.0056, and yellow indicates non-significant p-values > 0.0056.