Target acquisition tasks are often augmented by automated aids to advise human observers during the detection process. The question arises whether these automated aids, by nature imperfect, should be implemented under all conditions. This study examines the efficacy of an imperfect automated aid in human target acquisition performance under conditions of high mental workload. Human observers performed a target acquisition task aided by an automated aid (cuer) of varying accuracy concurrently with a military tracking task. Results indicate that the automated aid can improve performance over the unaided condition when it is highly reliable. Evidence of dependence on the system by the observers was found. The thesis here is that the condition of high mental workload induced greater acceptance of and reliance on the automated aid by the observers, which manifested in the highly significant cue dependence results. Another element found in the observers' interaction with the automated aid, which could be a consequence of overreliance, was a high perceived reliability of the cuer, which led observers to respond more confidently to cued targets. These results can help increase the understanding of human behavior vis-à-vis working with automated aids when under conditions of high mental workload.