The ability to sustain attention and maintain goal-directed behaviour for extended periods of time is known as vigilance. It’s a life or death quality in a soldier. Lack of vigilance may not be so fatal in your line of work but you can imagine why increased vigilance would be good.
The purpose of the DARPA study was to examine the effect of tDCS in a vigilance task. tDCS significantly altered baseline task-induced physiologic and behavioral changes. Behavioral measures showed a significant improvement in target detection performance with tDCS compared to the sham stimulation.
The program settings used in this study are shown below.