2022-09-06, Merks, Sarah, Sauer, Juergen, Schwaninger, Adrian

2021-03-04, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2020, Hügli, David, Merks, Sarah, Schwaninger, Adrian

Using a simulated X-ray screening task, we tested 122 airport security screeners working with the support of explosives detection systems for cabin baggage screening (EDSCB) as low-level automation. EDSCB varied systematically on three automation reliability measures: accuracy, d’, and positive predictive value (PPV). Results showed that when unaided performance was high, operator confidence was high, and automation provided only small benefits. When unaided performance was lower, operator confidence was lower, and automation with higher d’ provided large benefits. Operator compliance depended on the PPV of automation: We found lower compliance for lower PPV. Automation with a high false alarm rate of 20% and a low PPV of .3 resulted in operators ignoring about one-half of the true automation alarms on difficult targets—a strong cry-wolf effect. Our results suggest that automation reliability described by d’ and PPV is more valid than using accuracy alone. When the PPV is below .5, operators should receive clear instructions on how to respond to automation alarms.

2019-09-10, Hügli, David, Merks, Sarah, Schwaninger, Adrian

This study investigated human-automation interaction with automated explosives detection systems for cabin baggage screening (EDSCB) depending on automation reliability. We conducted a laboratory experiment with 118 screeners of an international airport, which performed in a simulated X-ray screening task. We tested human-machine system performance in four test conditions: one baseline group with no EDSCB and three practically relevant EDSCB algorithms that varied systematically in automation reliability measures, i.e. accuracy, d’ and positive predictive value (PPV). Screeners had to detect improvised explosive devices, bare explosives, guns, or knives. EDSCB increased human-machine system performance for detecting explosives due to direct cueing of targets. The benefit of EDSCB depended on target difficulty and automation reliability in terms of d'. High false alarm rates caused a cry-wolf effect, especially for bare explosives. PPV of EDSCB explained screeners' compliance best. Our results suggest that operators use a probability-matching decision strategy, in particular for difficult targets

2022-05-04, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2020-11-24, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2019-09-20, Merks, Sarah, Hügli, David, Hättenschwiler, Nicole, Schwaninger, Adrian

2021-10, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2020-03-18, Hügli, David, Merks, Sarah, Schwaninger, Adrian

2019-09-11, Isenschmid, Myrta, Hättenschwiler, Nicole, Merks, Sarah, Schwaninger, Adrian

The screening of hold baggage at airports is currently changing from 2D to 3D imaging. In this context, we compared visual inspection performance of screeners using 2D imaging versus 3D imaging versus 3D imaging following a specific on-screen alarm resolution protocol (OSARP). In a simulated hold baggage screening task, professional screeners had to decide whether X-ray images contained an improvised explosive device or not. Results showed that there was no difference in detection performance (d') between 2D and 3D imaging. Visual inspection with 3D imaging following an OSARP resulted in higher detection performance compared to 2D and 3D imaging, but also in a more neutral response bias and longer reaction times. In conclusion, screeners currently working with 2D technology do not need extensive and specific training to achieve comparable detection performance with 3D imaging. However, the application of an OSARP has the potential to further increase screeners’ detection performance.