Abstract
Human reliance on computers to execute job-related tasks has increased immensely with advances in computer technology. One application of computers that is growing rapidly is performing military maneuvers in defense industries such as radar systems or geographical intelligence systems. In a military information station, operators have to carry out data analysis, assessment, and decision-making in a short time. Each decision which may be decided in milliseconds is a matter of life and death for soldiers. Therefore, the operators’ task performance is affected by stress and time load. This makes the interface of the systems to be one of the most important factors for reducing the human’s cognitive load of preventing safety-related accidents. This study conducted three experiments to investigate the common warfighting symbology interface design on human performance and cognitive load. The first experiment investigated the human performance on color discrimination in visual display terminals. It may be affected by illuminant colors, the level of ambient illumination and background colors of the monitor. A complete factorial (2 × 3 × 3) within-subject design was used. The independent variables were three illuminant colors (red, blue, and white), two ambient illumination levels (50 lux and 300 lux), and three background colors (black, blue and brown); the three dependent variables were the color discrimination ability (error scores), completion time and subject preference. The results showed that the illuminant colors and the screen background colors both significantly influenced human color discrimination ability (p < 0.01). The result of this research can be used in control room design when considering the effect of color. The second experiment investigated the visual search performance in visual display terminals. Visual search performance may be affected by target size, background type and the dimensions of the screen. Especially, when there is time pressure for operators to execute the search task in a military information station, visual search performance becomes more important. Thirty-six participants were recruited and a three-factor mixed design was used in which the independent variables were three screen dimensions (7, 15 and 21 inches), five icon sizes (visual angle 40, 50, 60, 70 and 80 min of arc) and two map background clutter types (topography displayed [TD] and topography not displayed [TND]). The five dependent variables were completion time, accuracy, fixation duration, fixation count and saccade amplitude. The results showed that the best icon sizes were 80 and 70 min. The 21 inches screen dimension was chosen as the superior screen for search tasks. The TND map background produced higher accuracy compared to that of TD background. The results of this research can be used in control room design to promote operators’ visual search performance. The third experiment extended the first and the second experiments to a simulated geographical intelligence system. The objective of this research was to investigate the influence of a simulated geographical intelligence system on operators’ cognitive load by galvanic skin response (GSR) and pupil diameter measures. The experiment was to examine the influence of operators on icon types (hollow and filled), icon sizes (visual angle 40, 60, and 80 min of arc) and map background clutters (TD and TND) in the geographical intelligence system (GIS). The results showed that operators’ cognitive load was lower under higher target/background difference. The search efficiency was well when hollow icons were presented on TND map background. The findings of this study can help the designers to develop more efficient and comfortable interfaces to fit users. Finally, some design specifications were recommended.