Airport and border security personnel are working to improve security practices and preparedness to prevent acts of terrorism. While they must guard against false positives that result in needless delays for travelers, they must also balance those against the grave costs of missing a threat. In support of a study investigating individual differences in vigilance tasks, the authors have developed and pilot-tested a controllable simulated airport security screening environment. The simulation enables, in a more realistic setting than typically possible, research focused on understanding issues such as:

• Implications when task instructions differ in detail;

• Implications when task instructions require simultaneous search for multiple classes of objects, or when the classes have differing security implications;

• Implications of distraction (e.g., noise, activity, both expected and not) in the environment.

These factors allow for an examination of distinct contributions to attentional processing, top-down executive control and bottom-up perceptual processing. Both processes need to be considered to adequately address perception of and attention to items in the environment. Ongoing basic studies are comparing use of the simulated environment against traditional techniques. Ongoing work with Government security personnel is directing the application to existing training needs to better determine how training can influence performance.