Department of Psychology and Ergonomics, Technische Universität Berlin, Berlin, Germany.
Sci Rep. 2024 Oct 3;14(1):23003. doi: 10.1038/s41598-024-72210-8.
Human redundancy is often used in safety-critical domains to help protect against errors. For example, mammograms are read by two radiologists, or the dose of a drug is calculated by two physicians who perform the task redundantly one after the other. However, the expected reliability gain may be compromised by social loafing (SL), i.e., a reduction of individual effort caused by the team setting. In two laboratory studies, we therefore investigated whether different forms of human redundancy cause SL and impact task outcome. In each experiment, about 20 participants inspected images alone for rare targets, while 40 participants worked in teams of two, either performing the first or second inspection. We measured effort using inspection time and inspection area, and measured task outcome using the number of detected targets and false alarms. While there was no transfer of target marks in experiment 1 (blinded redundancy), the second inspectors in experiment 2 saw marks set during the first inspection (nonblinded redundancy). In experiment 1, data revealed no indications of SL but increased time, area covered, detections and false alarms for team-based relative to solo performance. In experiment 2, teams clearly adapted their inspection intensity. The second inspectors searched the images significantly shorter than the first inspectors. While detected targets did not differ between the two redundant groups, the second inspectors were found to produce significantly fewer false alarms than the first inspectors. However, the advantage of detected targets and area coverage still favored the teams. Thus, the principle of redundancy was effective in both forms of sequential redundancy, even if it led to different behaviors and perceptions at the individual level.
人为冗余常常被用于安全关键领域，以帮助防止错误。例如，乳房 X 光片由两名放射科医生阅读，或者药物剂量由两名医生计算，他们冗余地依次执行任务。然而，预期的可靠性增益可能会因社会惰化（SL）而受到影响，即团队环境导致个体努力的减少。在两项实验室研究中，我们因此调查了不同形式的人为冗余是否会导致 SL 并影响任务结果。在每项实验中，大约 20 名参与者单独检查图像中的稀有目标，而 40 名参与者以两人一组的形式工作，要么执行第一次检查，要么执行第二次检查。我们使用检查时间和检查区域来衡量努力程度，并用检测到的目标数量和误报来衡量任务结果。虽然在实验 1（盲式冗余）中没有目标标记的转移，但在实验 2（非盲式冗余）中，第二个检查员看到了第一个检查员在检查过程中设置的标记。在实验 1 中，数据没有显示出 SL 的迹象，但团队表现的时间、覆盖面积、检测和误报都有所增加。在实验 2 中，团队明显调整了他们的检查强度。第二个检查员的搜索时间明显短于第一个检查员。虽然两组冗余的检测到的目标没有差异，但发现第二个检查员的误报明显少于第一个检查员。然而，检测到的目标和面积覆盖的优势仍然有利于团队。因此，冗余原则在两种形式的顺序冗余中都是有效的，即使它导致了个体层面不同的行为和认知。
