The U.S. Transportation Security Administration has "red teams" who try to sneak dangerous items through airport security. The security personnel often fail up to 95% of these tests. Is this high failure rate to be expected because of habituation to visual stimulus? Specifically, a screening agent is expected to find a single weapon amidst thousands of X-rays without a weapon.

If this is habituation, are there techniques for reducing its impact in scenarios such as this?

  • $\begingroup$ Huh: an interesting question! This may foster mostly opinionated answers, though... All the same, I wonder to what degree this has to do with the false positive paradox $\endgroup$
    – mflo-ByeSE
    Commented Jun 19, 2017 at 22:52
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    $\begingroup$ Jobs like this (radiology, security, quality assurance, etc) are getting replaced with AI, which is more accurate and not susceptible to habituation or fatigue. $\endgroup$
    – Arnon Weinberg
    Commented Jun 19, 2017 at 22:58
  • $\begingroup$ For clarification, is this question asking if habituation is directly and solely responsible for inaccurate airport screenings, or if it is one facet of inaccurate airport screenings? I believe I have an answer either way, but would like to know how to word it. $\endgroup$ Commented Jun 22, 2017 at 4:39
  • $\begingroup$ I intended to ask whether habituation was a substantial factor contributing to the inaccurate screenings. If there are other significant factors, I'd enjoy hearing about those too. $\endgroup$
    – mndrix
    Commented Jun 22, 2017 at 12:57

1 Answer 1


The main reason for these failures is mental fatigue and lost of concentration, in conjuction with the weak target signals.

Vigilance decrement is defined as "deterioration in the ability to remain vigilant for critical signals with time, as indicated by a decline in the rate of the correct detection of signals". Vigilance decrement is most commonly associated with monitoring to detect a weak target signal. Detection performance loss is less likely to occur in cases where the target signal exhibits a high saliency. ... Under most conditions, vigilance decrement becomes significant within the first 15 minutes of attention, but a decline in detection performance can occur more quickly if the task demand conditions are high ... More recent studies indicate that vigilance is hard work, requiring the allocation of significant cognitive resources, and inducing significant levels of stress.

Habituation plays very little role in these failures.

Early theories of vigilance explained the reduction of electrophysiological activity over time associated with the vigilance decrement as a result of neural habituation. ... More recent ERP studies indicate that when performance declines during a vigilance task, N100 amplitude was not diminished. These results indicate that vigilance is not the result of boredom or a reduction in neurological sensitivity

Training and motivation can decrease failures.

Training and practice significantly reduce the vigilance decrement, reduce the false alarm rate, and may improve sensitivity for many sustained attention tasks. Training improvements may also occur due to the reduced mental workload associated with task automaticity. In pilotage and airport security screening experiments, trained or expert subjects exhibit better detection of low salience targets, a reduction in false alarms, improved sensitivity, and a significantly reduced vigilance decrement. In some cases the vigilance decrement was eliminated or not apparent.


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