Prevalence Effect
In situations where people are expected to be aware and recognize an event that doesn’t occur very often, then often people will struggle to recognize the event. This is can be a problem in cases like TSA security checks; the TSA officer has to be vigilant in order to identify dangerous objects in people’s luggage, but as most luggage does not contain these objects it can be easy for the prevalence effect to occur and for the officer to miss dangerous objects when they do show up. The TSA combats this by regularly planting fake images of guns and then informing the officer that it was just a test when they identify them.
