The purpose of this research was to gain a better understanding of how specific aspects of cognitive performance are influenced by operating in lethal environments with the aim of incorporating any helpful insights into the operations performed by human intelligence collectors. Gaining a better understanding of any negative cognitive effects could enable leaders in the intelligence community to take mediating action resulting in a more efficient enterprise. Simulating the cognitive processes expected to be at play in lethal environments was accomplished by utilizing a technique known as mortality salience that has been shown to induce specific psycho-social reactions in individuals. Cognitive performance was tested by using the simple reaction time, attentional switching, and Stroop tests of the Automated Neuropsychological Assessment Metrics (ANAM4TM). Memory recall was tested by asking participants to recall categorized items after watching a video of a fictional intelligence source. This study found mortality salience had a statistically-significant influence on certain aspects of executive function as well as memory recall and suggest the etiology of mortality salience effects are most consistent with modern understandings of cognitive bias. As such, the term “mortality bias” is proposed for future investigations and explanations of the phenomenon.