The ability to detect threats is particularly critical for Soldiers who serve in the dynamic and irregular battlefields of the U.S. Army's current Operational Environment (OE). Threat detection encompasses a variety of cognitive and perceptual skills, such as attention management, pattern matching, reasoning about threats, and change/anomaly detection. Training the cognitive skills associated with effective threat detection takes an understanding of the threat detection processes engaged in by experienced Soldiers. To identify these cognitive skills, research was conducted to understand threat detection in the OE and to differentiate between the threat detection performance of more and less experienced Soldiers. From these data, a computer-based training exemplar was developed with the goal of enhancing Soldier ability to detect animate (i.e., human) and inanimate (i.e., IEDs) threats. This paper presents research findings that suggested time pressure, threat relevance, and experience played a role in threat detection performance. A threat search task demonstrated that less experienced Soldiers were more susceptible to time pressure with accuracy increasing slightly with the number of deployments. Results also revealed that all Soldiers could infer threat-relevant locations and appropriately focus their attention on those areas as well as identify threatrelevant changes. Interview analysis provided insight into the reasoning of more and less experienced Soldiers. Less experienced Soldiers tended to make context-free procedurally based statements, indicating they did not have mental models to draw from to make specific interpretations of the situations in the photos. These finding indicated that Soldiers, even in threat search tasks using static photos, directed their search to relevant threats rather than randomly over the photo, making this useful stimulus for training. From this research, a computer-based training prototype was created to improve Soldier ability to identify relevant threats, detect relevant changes, and develop causal reasoning skills applicable to the operational environment.