Touch Zone Sizing for Mobile Devices in Military Applications

Of late, the desire to adopt devices such as Apple iPads for use in military cockpits (for example, as "electronic flight bags" to replace paper-based reference materials) has increased. Two sources for touch screen design guidance for military applications are MIL-STD-1472 and manufacturer (e.g., Apple) interface style guides. However, minimum touch zone size and separation recommendations vary considerably between these sources. This study assessed the impact of manipulating touch zone size and separation in ungloved and gloved conditions. Despite a small sample size (n = 6), significant main effects of gloves and sizing guidelines were found. Unsurprisingly, participants were less accurate hitting targets on the first try when wearing gloves. Participants made no errors (i.e., activating a button other than the target) in the MIL-STD-1472 sizing condition irrespective of gloves. These results indicate that following MIL-STD-1472 guidelines reduces the likelihood of activation errors at the cost of decreased information density.