Subjective state constructs are defined within the traditional domains of affect, motivation, and cognition. Currently, there is no overarching state model that interrelates constructs within the different domains. This article reports 3 studies that provide converging evidence for 3 fundamental state dimensions labeled task engagement, distress, and worry that integrate constructs across the traditional domains. Study 1 differentiated the state dimensions by factor analysis of the scales of the Dundee Stress State Questionnaire (G. Matthews et al., 1999). Study 2 showed differential state response to performance of tasks making different cognitive demands. Study 3 showed that states are correlated with differing patterns of appraisal and coping. The 3 stress state dimensions provide a general descriptive framework consistent with transactional accounts of stress and performance.

Robertson, Manly, Andrade, Baddeley, and Yiend (1997) proposed that the decline in performance efficiency over time in vigilance tasks (the vigilance decrement) is characterized by "mindlessness" or a withdrawal of attentional effort from the monitoring assignment. We assessed that proposal using measures of perceived mental workload (NASA-TLX) and stress (Dundee Stress State Questionnaire). Two types of vigilance task were employed: a traditional version, wherein observers made button-press responses to signify detection of rarely occurring critical signals, and a modified version, developed by Robertson et al. to promote mindlessness via routinization, wherein button-press responses acknowledged frequently occurring neutral stimulus events and response withholding signified critical signal detection. The vigilance decrement was observed in both tasks, and both tasks generated equally elevated levels of workload and stress, the latter including cognitions relating to performance adequacy. Vigilance performance seems better characterized by effortful attention (mindfulness) than by mindlessness. Actual or potential applications of this research include procedures to reduce the information-processing demand imposed by vigilance tasks and the stress associated with such tasks.

This paper presents a descriptive analysis of over 1000 global NASA Task Load Index (TLX; Hart & Staveland, 1988) scores from over 200 publications. This analysis is similar to that which was suggested by Hart (2006). The frequency distributions and measures of central tendency presented will aid practitioners in understanding global NASA-TLX scores observed in system tests.

Military cognitive readiness is a somewhat new concept that has been defined many ways. In this article, I review these definitions and propose that cognitive readiness is not just one construct, but three inter-related constructs akin to the military levels of war and readiness (tactical, operational, & strategic). Each of these constructs requires cognitive performance in complex, uncertain, and stressful military operations. However, the nature of performance is different for each. Thus, each level of cognitive readiness requires different measures. As a first step in the development of measures for operational and strategic cognitive readiness, a review of research related to predicting cognitive performance in complex, uncertain, and stressful operations was conducted. From this review a set of inherent psychological factors and their measures were identified. The article concludes by indicating what future steps are needed to develop measures of both operational and strategic readiness.

The system usability scale (SUS;Brooke, 1996) is an instrument commonly utilized in usability testing of commercial products. The goal of this symposium is to discuss the validity of the SUS in usability tests and beyond. This article serves as an introduction to the symposium. Specifically, it provides an overview of the SUS and discusses research questions currently being pursued by the panelists. This current research includes: defining usability norms, assessing usability without performing tasks, and the use of SUS for ergonomics. In addition to this paper, there are four other papers in the symposium, which discuss the impact of experience on SUS data, the relationship between SUS and performance scores, the linkage between SUS and business metrics, as well as the potential for using SUS in test and evaluation for military systems.