Stress is a concept that can be studied using a variety of theoretical approaches, with a focus on the individual’s perceptions, the external stressor, or the physiological reactions of stress responding. However these approaches are often used independently, when they can be used complementarily to understand the nuanced relationship between the individual and the situation when appraising stressors as challenges or threats. The current study examined the relationship between individual differences in perceptions, situational strength (both as a categorical and a continuous predictor), and physiological reactions in a leadership task. Situational strength and leadership self-efficacy were found to interact, such that those high is LSE reported more appraisals of challenge as situational strength increased. / Master of Science / Stress is a widely known concept that has been studied in various ways (individual perceptions, situational characteristics, physiology, etc.). However these approaches are often used independently, when they can be used together to more fully understand the process of how individuals appraise stressors. The current study examined the relationship between the previously mentioned approaches within a leadership task. Situational strength and leadership self-efficacy (LSE), or one’s perceived capabilities to perform leadership duties, were found to interact, such that those high is LSE reported more appraisals of challenge as situational strength increased.

This paper investigated the suggestion that situational judgment is a multidimensional evaluation methodology that assesses task and/or contextual job knowledge, and in any given situational judgment test (SJT), there may be items that better tap contextual knowledge while other items may better tap task knowledge. 233 undergraduate students completed questionnaires containing a situational judgment test, personality questionnaire, and cognitive ability test. Results supported the hypothesis that suggested personality significantly predicts contextual knowledge over and above cognitive ability, but did not support the prediction that cognitive ability significantly predicts task knowledge above and beyond personality. Preliminary results suggest that the lack of support for H2 may be due to the SJT utilized in this study, which appears to have tapped primarily contextual knowledge domains. Implications and directions for future research are suggested. / Master of Science

New sensor and display technologies are expected to enhance the performance of soldiers by providing them more information about the battlefield. However, there is concern that greater quantities of information and increases in mental workload might cause distraction, reduce attention to dangers in the immediate environment, and threaten soldier survival. The purpose of this laboratory investigation was to quantify the effects of increases in mental workload on one of the soldier's most basic tasks --- avoiding ground hazards while walking. The participants were 12 U.S. Army infantry soldiers. The study was conducted on a treadmill that was modified to provide the participants a view of impending ground hazards up to 5 meters forward of their walking position. The study was a 2X3 fixed factor design with two levels of terrain difficulty (No Hazards and Hazards) and three levels of mental workload (No Load, Moderate load, and High load), all as within-subject effects. Mental workload was increased from the "No Load" to a "Moderate" level by requiring the participants to perform a mental arithmetic task while walking. Mental workload was increased from the "Moderate" to the "High" level of load by increasing the difficulty of arithmetic problems. The dependent variables included time and error in the performance of the mental arithmetic task, the mean and standard deviation in step length and step rate, the number of ground hazards contacted, and subjective ratings of workload. The participants" scores on the Armed Forces Qualification Test (AFQT) and subtests of the Armed Services Vocational Aptitude Battery (ASVAB) related to arithmetic skills were also obtained. The results of the investigation indicated that when the participants were required to avoid hazards, step length decreased and step rate increased, as was expected. Both measures of gait increased in variability. Subjective ratings of physical demand and effort obtained across the three levels of mental workload increased significantly, along with perceptions of workload associated with a perceived decline in performance. Subjective ratings obtained across the two levels of terrain difficulty indicated that ratings of mental demand and effort increased with each increase in level of mental workload. When the participants were confronted with the more difficult arithmetic problems at the "High" level of mental workload, time and error in performing the mental arithmetic task increased as did ratings of temporal demand, frustration, and workload attributable to a perceived decline in performance; however, subjective ratings of physical demand decreased. Interactions found between terrain difficulty and mental workload indicated that differences in ratings of performance and overall workload scores between the two levels of terrain difficulty decreased significantly between the "No Load" and the "Moderate" level of mental workload, and converged at the "High" level of mental load. Although relationships were found between perceived workload, gait, and performance of the mental arithmetic and hazard avoidance tasks, the analysis did not reveal a significant effect of mental workload on the number of hazards contacted. Some participants tended to contact more hazards at the "High" level of mental workload than at the "No Load" or the "Moderate" levels, as expected. However, other participants tended to contact more hazards at the "Moderate" level of mental load than at either of the two extremes. Still other participants tended to contact more hazards at the "No Load" level of mental workload than at the "Moderate" or the "High" levels. Correlations were found between subjective ratings of workload, mental arithmetic performance, and scores on the AFQT and subtests of the ASVAB related to arithmetic skills, but no relationships were found between test scores and performance of the hazard avoidance task. However, when test scores were used as covariates in the analysis of mental arithmetic performance, the findings revealed that the number of correct responses to the arithmetic problems decreased when the participants were required to avoid hazards. The results of the study may support the belief that the allocation of limited resources will vary based on past experience and other individual differences, and that the amount of resources allocated to a task may be influenced by the difficulty of the task, criteria for performance, and the motivation of the individual. / Master of Science

Situational judgment tests are analogous to earlier forms of "high fidelity" simulations such that an ostensible paradox emerges in the consistent finding of criterion-referenced validity but almost complete lack of construct validity evidence. The present study evaluates the extent to which SJT's can demonstrate convergent and discriminant validity by analyzing a SJT from a multitrait-multimethod perspective. A series of hierarchically nested confirmatory factor models were tested. Results indicate that the SJT demonstrates convergent and discriminant validity but also contains non-trivial amounts of construct-irrelevant method variance. Wide variability in the content and validation methods of SJT's are discussed as the reason previous attempts to find construct validity have failed. / Master of Science

Approved for public release, distribution is unlimited / Due to the rapid development of technology, many simple tasks can now be automated, leaving more difficult and cognitive tasks such as planning, decision making and design to teams. Technology also allows these teams to be distributed through time and space. While this is becoming more and more prevalent in the business world, distributed teams also exist in the military where the stresses are much different. One of the key factors associated with collaboration in military teams is situational awareness. This research used a commercial command and control type video game to investigate the issues of collaboration and situational awareness. The amount of information subjects had access to was varied to see if there was a significant impact upon their level of situational awareness which was measured by the accuracy of maps that the subjects drew. Results from this research may provide insight into how much information is needed by distributed teams and when they need it. Ideas for future research in this area have also been proposed. / Lieutenant Commander, United States Navy

Organizational environment (broadly conceptualized) has been shown to have an important influence on job choice (Chapman, Uggerslev, Carroll, Piasentin & Jones, 2005). Controversy exists, however, regarding how to operationalize organizational environment in a way that is both useful and parsimonious. Consistent with the perspective that situational strength meets these criteria (Meyer & Dalal, 2009), the present study found that participants were attracted to hypothetical organizations that were strong with respect to clarity, consistency, and consequences, but weak with respect to constraints. Further, individual differences in various psychological needs were shown to influence the strength of the relationship between situational strength and organizational attraction; for example, those with a high need for achievement were particularly attracted to organizations that were high with respect to consequences. These results not only contribute to the job choice literature, but also suggest that situational strength is more than just a moderator of personality-outcome relationships – it is an important psychological construct in and of itself, with its own nomological network that is worthy of continued research attention.

"Strong situations" have been shown to decrease behavioral variability, thereby attenuating the criterion-related validity of non-ability individual differences for criteria such as job performance (Barrick&Mount, 1993; Meyer, Dalal,&Bonaccio, 2009). However, it has been suggested that individuals, based on individual differences in implicit motives, may impute discrepant psychological meaning to social stimuli like situational strength--a process sometimes known as differential framing (James&McIntyre, 1996). If different psychological interpretations are attached to strong situation stimuli (e.g., Meyer, Dalal,&Hermida, 2010), an interesting behavioral "double-edged sword" is possible. On the one hand, behaviors pertinent to "primary criteria" (i.e., criteria for which external situational influences and pressures lead to targeted behavioral homogeneity) may occur among those who would not normally engage in them. But, at the same time, behaviors pertinent to "secondary criteria" (i.e., unintended, unforeseen, and potentially reactionary behaviors and/or attitudes) might also increase for some individuals (i.e., those with certain implicit motive characteristics). In other words, high situational strength may simultaneously constrain behavioral variability in primary criteria while serving as a stimulus for differential framing, thereby expanding variability on secondary criteria. The purpose of the present dissertation was twofold: 1) to explore the degree to which situational strength is differentially framed, and 2) to ascertain how the differential framing of situational strength may lead to unintended secondary outcomes. Study 1 findings indicate that, to a partial extent, situational strength is differentially framed by individuals with different implicit motives. Study 2 findings are largely consistent with extant situational strength theory, though partially inconsistent with study predictions.

<p>    </p> <p>Space has become ever more crowded since the launch of Sputnik. The need for predictions of possible collisions between space objects has only ever grown. The development of space, particularly around Earth, increases the density of space objects and skyrockets the number of close approaches between these objects, called conjunctions. This investigation is conducted in the context of probability dilution, a phenomenon leading to a false negative collision prediction where increasing positional uncertainty decreases the predicted likelihood of a collision. Dilution is investigated along two avenues: how to generate accurate collision predictions in an efficient manner and how to obtain better input data with which to make these predictions. Along the first avenue, this research presents a novel analytical rectan- gular probability of collision expression as well as a variety of new covariance scale factor formulations for maximum collision probability that indicate the maximum possible collision risk for any conjunction. Along the second avenue, this research tests new sensor tasking regimes to mitigate dilution, ultimately showing that while dilution can be reduced, shrink- ing the positional covariance through optimal measurement updates may not be enough to avoid false negatives in orbital conjunctions. </p>

<p dir="ltr">Characterizing unknown space objects is an important component of robust space situational awareness. Estimating the shape of an object allows analysts to perform more accurate orbit propagation, probability of collision, and inference analysis about the object’s origin. Due to the sheer distance from the camera combined with diffraction and atmospheric ef- fects, most resident space objects of interest are unresolved when observed from the ground with electro-optical sensors. State of the art techniques for object characterization often rely on light curves — the time history of the object’s observed brightness. The brightness of the object is a function of the object’s shape, material properties, attitude profile, as well as the observation geometry. The process of measuring real light curves is complex, involv- ing the physics of the object, the sensor, and the background environment. The process of recovering shape information from brightness measurements is known as the light curve shape inversion problem. This problem is ill-posed without further assumptions: modern direct shape inversion methods require that the attitude profile and material properties of the object is known, or at least can be hypothesized. This work describes improvements to light curve simulation that faithfully model the environmental and sensor effects present in true light curves, yielding synthetic measurements with more accurate noise characteris- tics. Having access to more accurate light curves is important for developing and validating light curve inversion methods. This work also presents new methods for direct shape inver- sion for convex and nonconvex objects with realistic measurement noise. In particular, this work finds that improvements to the convex shape inversion process produce more accurate, sparser geometry in less time. The proposed nonconvex shape inversion method is effective at resolving singular large concave feature.</p>

<p dir="ltr">With the increase in planned space missions in cislunar space, it is necessary to study the ability of observers to observe and track objects in this regime. This thesis focuses on creating a sensor tasking algorithm for constellations of optical observers to efficiently observe cislunar objects. The circular restricted three body problem is used for the dynamics of the objects while the bi-circular restricted four body problem is used to approximate the position of the sun.</p><p dir="ltr">A new way of discretizing the field of regard is proposed that respects the observers field of view on the unit sphere. A method for providing feedback to the observer in a delayed feedback environment is applied to mean state, single Gaussian, and particle representations of uncertainty. The method of determining a scaling coefficient for Sanson’s probability of detection is recorded. Sanson’s probability of detection is studied for determining the correct effective aperture dimensions of an optical observer. An approximation is presented for expediting calculations of Sanson’s probability of detection. An uncertainty propagation analysis shows there is an efficient number of particles to use for particle uncertainty far below the required number for a full Monte Carlo particle uncertainty representation. </p><p dir="ltr">Mean state, single Gaussian and particle methods of uncertainty characterization are compared in a cislunar simulation showing the benefits of the particles solution over other forms of uncertainty characterization. Particles are not only an effective uncertainty representation in a delayed feedback environment, they are computationally feasible for the sensor tasking problem. The performance of the particle algorithm for a constellation of observers is evaluated in a simulated small satellite breakup in a Lyapunov orbit and a simulated breakup of the proposed Lunar Gateway. The performance of observers in direct retrograde, low lunar, geosynchronous, and northern Halo orbits are evaluated in the breakup simulations. Results from these simulations show that observers in low lunar and Halo orbits can be valuable observation standpoints in breakups around the near-Moon region of cislunar space.</p>