310 Detect Concealed Weapons

Based on research by Sweet, Dawn. M., Meissner, Christian. A., & Atkinson, Dominick. J., 2017.  written by Bethany Wellman, M.S.

Terrorist attacks seem all too frequent. To act preventively, how accurate are security personnel in identifying threat indicators in potential offenders’ behavior?

Iowa State University psychologists conducted three experiments to assess accuracy of law enforcement versus untrained personnel to detect concealed weapons.

In study one, about 50 officers and 50 students assessed whether a person was concealing a handgun and reported any behavioral indicators supporting their decision. Both officers and participants poorly identified the concealed weapon. In study two, in three videos showing several students with backpacks, both groups correctly identified the ‘concealed bomb’ only 44% of the time. In Study three, officers and students evaluated a series of videos where one of 2 persons concealed a “bucket of water” in a backpack. Again, there were no significant differences between law enforcement and students, both scored only slightly above chance. However, in all trials, the more experience an officer had, the more likely they said weapons were concealed. The more experienced officers were less accurate.

Sadly, we humans including trained police, can’t detect who is dangerous. With experience, we are often more likely to perceive threats when they are not there. High tech detect needed!


Sweet, D. M., Meissner, C. A., & Atkinson, D. J. (2017). Assessing Law Enforcement Performance in Behavior-Based Threat Detection Tasks Involving a Concealed Weapon or Device. Law and Human Behavior41(5), 411-421.

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