Effects of Simultaneous Alarms on Resolution Heuristics

Automated signaling systems are frequently used to direct operator attention to potential hazards. Although these automated systems can lead to enhanced human performance, factors such as degraded alarm signal reliability and lack of trust can undermine the potential benefits of automation (Breznitz, 1984; Rice, 2009, Wickens & 2007). Additionally, work by Gilson, Mouloua, Graft, and McDonald (2001), as well as Keller and Rice (2009), suggest that an alarm contained within a larger array of alarms should not be evaluated individually. Due to the increasing use of multiple alarms in complex environments such as operating rooms and cockpits (Konkani, Oakley, & Bauld, 2012; Woods, Suter, & Billings, 1997), it is important to identify reaction strategies that may and should be used when an unreliable alarm is in the presence of other alarms. Accordingly, the influence of reliability level and the number of additional activated alarms on objective trust, reaction time, and acceptance rate with a 12-alarm array was evaluated using a 2 x 12 split-plot factorial design. Overall a significant linear trend was observed in objective trust measures as the number of additional activated alarms (p \u3c .001). This finding indicates the number of additional activated alarms, instead of the given alarm reliability, was used to calibrate objective trust. Reaction time was found to be quadratic (p \u3c .001). Acceptance rate followed a cubic trend (p \u3c .001), with significant quadratic (p = .02) and significant linear (p \u3c .001) derivative trends. This suggests participant response changed from alarm dismissal to acceptance near 50% of alarm array activation. Finally, there was a significant effect of reliability level (p \u3c .001) on acceptance rate, although no significance differences were found between the 50% and 75% groups. Overall, the results constitute evidence for an extension of probability matching theory based on percent system activation and indicate the need to minimize alarms in display design

Alarm handling for health monitoring: operator strategies used in an electrical control room of a rail network

Alarm management is a key component of the successful operation of a prognostic or health-monitoring technology. Although alarms can alert the operator to critical information, false alarms and alarm flooding can cause major difficulties for successfully diagnosing and acting upon infrastructure faults. Human factors approaches seek to design more-effective alarm systems through a deep understanding of the contextual factors that influence alarm response, including strategies and heuristics used by operators. This paper presents an extensive analysis of alarm-handling activity in the setting of an Electrical Control Room on the rail network. The analysis is based on contextual observation, and the application of a time-stamped observation checklist. Functions, performance requirements, and general operating conditions that influence alarm handling are presented, delineating the typical operational constraints that need to be considered in the design and deployment of asset-based alarm systems. The analysis of specific alarm-handling incidents reveals the use of specific strategies that may bias operator performance. Implications for the design of health-monitoring systems are discussed

Behavioral Influences Of Proximal Alarms

Confidence in and responses to an unreliable test alarm were studied in the presence of nearby unspecified alarms. The test alarm\u27s reliability rate was represented as averaging true only 50% or 60% of the time. Confidence or response rates ranged proportionately from 23% to 97% with the number of active alarms within 5, 6, 7, or 9 annunciator arrays. Adjacent alarms resulted in confidence estimates that were higher (by about 10%) than those with the same number of active alarms spaced up to 3 positions away. Simultaneously activated alarms resulted in a more than 20% increase in true responses compared with the same number of alarms offset in time by up to 32 s, regardless of which came first. Active alarms known to be functionally related to, or independent of, the test alarm substantially raised or lowered responding but did not completely overcome prior effects. These findings indicate that presumptions that operators\u27 responses are not influenced by nearby alarms, regardless of their function, may be unwarranted. Applications of this research include suggestions to improve responding and training recommendations

Behavioral influences of proximal alarms

Confidence in and responses to an unreliable test alarm were studied in the presence of nearby unspecified alarms. The test alarm\u27s reliability rate was represented as averaging true only 50% or 60% of the time. Confidence or response rates ranged proportionately from 23% to 97% with the number of active alarms within 5, 6, 7, or 9 annunciator arrays. Adjacent alarms resulted in confidence estimates that were higher (by about 10016) than those with the same number of active alarms spaced up to 3 positions away. Simultaneously activated alarms resulted in a more than 20016 increase in true responses compared with the same number of alarms offset in time by up to 32 s, regardless of which came first. Active alarms known to be functionally related to, or independent of, the test alarm substantially raised or lowered responding but did not completely overcome prior effects. These findings indicate that presumptions that operators\u27 responses are not influenced by nearby alarms, regardless of their function, may be unwarranted. Applications of this research include suggestions to improve responding and training recommendations