Impact of Icon Design Variables on Visual Search Behavior in Computer Numerical Control Machine Interfaces: A Comparison of Younger and Elderly Workers

Abstract

With the acceleration of global aging and the implementation of progressive retirement policies, elderly workers continue to remain active on the frontlines of industrial production worldwide. Computer Numerical Control (CNC) machine tools, as representative equipment in manufacturing, rely on control panel icons to convey critical information and guide operations. This study utilized eye-tracking technology to examine the differences in visual search efficiency between elderly and young workers when interacting with various visual representations of CNC machine tool icons. A total of 20 elderly and 20 young workers participated, with eye-tracking metrics including Area of Interest (AOI) fixation duration, AOI fixation count, and search time recorded. The results revealed that elderly workers had significantly longer search times compared to young workers. Icons with a line width of 1.5 px and a figure/background area ratio of 60% demonstrated the highest visual search efficiency. Based on the theory of white space, the analysis indicated that the interaction between line width and figure /background area ratio had a significant impact on all eye-tracking metrics. Excessively thick lines and large figure/background area ratios compressed active and passive white space, thereby reducing icon recognizability. Furthermore, the combination of visual representations affected visual search efficiency independently of age. These findings not only support the standardization of CNC machine tool icon designs but also provide empirical evidence for optimizing industrial interface designs tailored to elderly workers, holding significant theoretical and practical implications.

Keywords: Icon Design, Eye-Tracking, Aging Workforce, CNC Machine Tools