Vanessa Bowden

Situation Awareness Measures for Simulated Submarine Track Management

Objective: The aim of this study was to examine whether the Situation Present Assessment Method (SPAM) and the Situation Awareness Global Assessment Technique (SAGAT) predict incremental variance in performance on a simulated submarine track management task and to measure the potential disruptive effect of these situation awareness (SA) measures. Background: Submarine track managers use various displays to localize and track contacts detected by own-ship sensors. The measurement of SA is crucial for designing effective submarine display interfaces and training programs. Method: Participants monitored a tactical display and sonar bearing-history display to track the cumulative behaviors of contacts in relationship to own-ship position and landmarks. SPAM (or SAGAT) and the Air Traffic Workload Input Technique (ATWIT) were administered during each scenario, and the NASA Task Load Index (NASA-TLX) and Situation Awareness Rating Technique were administered postscenario. Results: SPAM and SAGAT predicted variance in performance after controlling for subjective measures of SA and workload, and SA for past information was a stronger predictor than SA for current/future information. The NASA-TLX predicted performance on some tasks. Only SAGAT predicted variance in performance on all three tasks but marginally increased subjective workload. Conclusion: SPAM, SAGAT, and the NASA-TLX can predict unique variance in submarine track management performance. SAGAT marginally increased subjective workload, but this increase did not lead to any performance decrement. Application: Defense researchers have identified SPAM as an alternative to SAGAT because it would not require field exercises involving submarines to be paused. SPAM was not disruptive, but it is potentially problematic that SPAM did not predict variance in all three performance tasks.

Uncovering continuous and transient monitoring profiles in event-based prospective memory

The present study implemented response time distribution modeling to better characterize context-specific attention dynamics underlying task interference due to possessing a prospective memory intention. During a three-phase paradigm in which prospective memory cues appeared only in the final phase, prospective memory performance was better when participants were informed at encoding of the context in which cues were to appear than when participants were not informed. Additionally, task interference increased during the third phase when the cue context was previously specified. Ex-Gaussian parameter estimates revealed that task interference during the third phase was due to a greater relative frequency of longer latencies, rather than an overall increase in latencies across all trials, suggesting that participants relied primarily on transient, rather than continuous, monitoring processes to support cue detection. Functionally, variability in transient and continuous monitoring profiles was predictive of prospective memory cue detection. More generally, the results from the present study suggest that ex-Gaussian parameter estimation procedures may provide a fruitful avenue for better understanding how attention is differentially allocated to ongoing tasks, what processes might underlie monitoring behavior, and how this behavior is related to eventual intention fulfillment.

Modulated textures with shape structures implied by a closed flow are processed globally

Radial frequency (RF) patterns, shapes deformed from circular by a sinusoidal modulation of radius, have been used to demonstrate global integration of shape information around a closed path by showing that the modulation depth required to detect shape deformation decreases rapidly as larger segments of the contour are modulated. In this psychophysical study we use a field of Gabor patches to examine integration of shape information in sampled RF patterns either alone or placed within an orientation-noise background and show that orientation-noise can be disregarded during the integration of modulation information. We also examine integration in modulated textures with local orientations that flow parallel or perpendicular to an underlying RF shape-structure. In using modulated textures comprising of elements with a random radial position but with orientation modulated such that it conforms to the local orientation of an RF pattern (RF texture) we demonstrate integration around texture patterns that imply shape. Texture patterns with element orientations locally orthogonal (RFO textures) to those of RF textures, however, exhibit a rate of decrease in modulation threshold, which is substantially reduced. When the textures are scrambled by permuting the polar positions of the patches the rate of decrease in threshold with increasing number of patches modulated in orientation is reduced for RF textures but not RFO textures. Detection of modulation in both scrambled textures is shown to be consistent with the detection of local cues. We conclude that implied closure in a modulated flow appears to be critical for global integration of textures.

Global shape processing: A behavioral and electrophysiological analysis of both contour and texture processing.

The number of corners on the boundary of a closed contour is thought to be particularly critical for shape detection and discrimination. The aim of the current study was to examine the relative contribution of the number of corners and the angle between corners to shape discrimination in complex visual scenes as well as to determine the time course and neural substrates of global shape processing based on the presence or absence of these specific features. In Experiment 1, event-related potentials were recorded while participants discriminated between two radial frequency (RF) patterns with the same maximum local curvature defining corners but varying arrangements of those corners. The results showed that the angle separating corners was more critical than the overall number of corners for discrimination performance. An enhanced negativity (posterior N220) over the occipital lobe was elicited following the presentation of an RF with three modulation cycles (RF3) but not following a circle, suggesting that the posterior N220 is sensitive to variation in curvature on a contour. In Experiment 2, we confirm the primary effect of the presence of corners on the amplitude of the posterior N220 component and extend the stimuli to include shapes defined by texture. Source localization on the N170 and N220 components was conducted in Experiment 2, and a source in cortical area V4 was identified. These findings suggest that corners contain vital information for the discrimination of shapes. Additionally, this study shows that the perceptual characteristics and neuroanatomical substrates can be detected using electrophysiological measures.

The Impact of Uncertain Contact Location on Situation Awareness and Performance in Simulated Submarine Track Management.

Objective: The aim of these studies was to examine the extent to which uncertainty in contact location in submarine track management affected operator situation awareness (SA), workload, and performance and whether operator SA predicted unique variance in performance. Background: We extend prior research by manipulating uncertainty in contact location and by including a sample of expert track managers in a submarine combat system. Method: In Experiment 1, university students completed a track management task. In Experiment 2, expert submariners were embedded in a real submarine combat system. Uncertainty was manipulated and SA was measured using the situation present assessment method. Results: Increased uncertainty led to higher student workload and moderately impaired SA and performance, and SA predicted incremental variance in performance. Uncertainty had no effect on expert SA or the accuracy of the tactical picture compiled. On average, experts took 20 s to accept SA queries (compared with 2.18 s for students). The time taken for experts to accept SA queries, but not their subsequent response to SA queries, was positively associated with their tactical picture accuracy. Conclusion: Uncertainty can negatively impact SA, workload, and performance. Some key findings from the laboratory were replicated using experts, but the fact that experts took on average 20 s to accept SA queries presents a challenge for using SPAM in submarine control rooms. Application: Contact location is uncertain due to the use of passive sonar and hostile deception. It is essential to measure track manager SA in order to inform work design and training.

Visual search reveals a critical component to shape

Objects are often identified by the shape of their contours. In this study, visual search tasks were used to reveal a visual dimension critical to the analysis of the shape of a boundary-defined area. Points of maximum curvature on closed paths are important for shape coding and it was shown here that target patterns are readily identified among distractors if the angle subtended by adjacent curvature maxima at the target patterns center differs from that created in the distractors. A search asymmetry, indicated by a difference in performance in the visual search task when the roles of target and distractor patterns are reversed, was found when the critical subtended angle was only present in one of the patterns. Performance for patterns with the same subtended angle but differing local orientation and curvature was poor, demonstrating insensitivity to differences in these local features of the patterns. These results imply that the discrimination of objects by the shape of their boundaries relies on the relative positions of their curvature maxima rather than the local properties of the boundary from which these positions are derived.

The effect of Virtual Reality in reducing preoperative anxiety in patients prior to arthroscopic knee surgery: A randomised controlled trial

Preoperative anxiety positively correlates with postoperative levels of pain, analgesic use and length of hospital stay. This preliminary study aimed to determine if the principle of distraction, using a relaxing Virtual Reality (VR) immersion, would reduce preoperative anxiety in patients undergoing arthroscopic knee surgery. Sixty patients were randomised into three groups (Standard care group, Virtual Reality group and iPad group). Anxiety scores (Hospital Anxiety and Depression Scale), Galvanic Skin Response (GSR), heart rate and blood pressure were measured pre and post intervention. The Standard care group received no intervention. The iPad group watched a video slideshow of beaches around the world and the VR group experienced a virtual beach immersion. Guided relaxation audio content (via headphones) was replicated across VR and iPad groups. Planned comparisons showed a significant difference between the average GSR measures at Time 1 and Time 2 between the Standard group and VR group. GSR measures for the Standard care group increased by 54 per cent from time 1 to time 2 and the VR and iPad groups reduced slightly, demonstrating an ameliorating effect on anxiety levels. A marginal difference between the Standard care group and VR group in anxiety change scores was reported. Whilst the VR condition reduced anxiety more than Standard care in both GSR and Anxiety change score measures, it provided no significant advantage over iPad condition. In conclusion, distraction using VR and iPad temporarily reduces self-reported anxiety levels and GSR measures compared to standard care in patients prior to knee arthroscopy. Further study is required to determine how long-lasting these benefits are in a clinical setting. The continuing advancements in VR technology, including immersion quality, present an opportunity to investigate the application of VR as a ‘digital pre-med’.

Forgetting induced speeding: can prospective memory failure account for drivers exceeding the speed limit?

It is generally assumed that drivers speed intentionally because of factors such as frustration with the speed limit or general impatience. The current study examined whether speeding following an interruption could be better explained by unintentional prospective memory (PM) failure. In these situations, interrupting drivers may create a PM task, with speeding the result of drivers forgetting their newly encoded intention to travel at a lower speed after interruption. Across 3 simulated driving experiments, corrected or uncorrected speeding in recently reduced speed zones (from 70 km/h to 40 km/h) increased on average from 8% when uninterrupted to 33% when interrupted. Conversely, the probability that participants traveled under their new speed limit in recently increased speed zones (from 40 km/h to 70 km/h) increased from 1% when uninterrupted to 23% when interrupted. Consistent with a PM explanation, this indicates that interruptions lead to a general failure to follow changed speed limits, not just to increased speeding. Further testing a PM explanation, Experiments 2 and 3 manipulated variables expected to influence the probability of PM failures and subsequent speeding after interruptions. Experiment 2 showed that performing a cognitively demanding task during the interruption, when compared with unfilled interruptions, increased the probability of initially speeding from 1% to 11%, but that participants were able to correct (reduce) their speed. In Experiment 3, providing participants with 10s longer to encode the new speed limit before interruption decreased the probability of uncorrected speeding after an unfilled interruption from 30% to 20%. Theoretical implications and implications for road design interventions are discussed.

Lowering thresholds for speed limit enforcement impairs peripheral object detection and increases driver subjective workload

Speed enforcement reduces incidences of speeding, thus reducing traffic accidents. Accordingly, it has been argued that stricter speed enforcement thresholds could further improve road safety. Effective speed monitoring however requires driver attention and effort, and human information-processing capacity is limited. Emphasizing speed monitoring may therefore reduce resource availability for other aspects of safe vehicle operation. We investigated whether lowering enforcement thresholds in a simulator setting would introduce further competition for limited cognitive and visual resources. Eighty-four young adult participants drove under conditions where they could be fined for travelling 1, 6, or 11km/h over a 50km/h speed-limit. Stricter speed enforcement led to greater subjective workload and significant decrements in peripheral object detection. These data indicate that the benefits of reduced speeding with stricter enforcement may be at least partially offset by greater mental demands on drivers, reducing their responses to safety-critical stimuli on the road. It is likely these results under-estimate the impact of stricter speed enforcement on real-world drivers who experience significantly greater pressures to drive at or above the speed limit.

Supervising High Degree Automation in Simulated Air Traffic Control

Implementing high degree automation in future air traffic control (ATC) systems will be crucial for coping with increased air traffic demand and maintaining safety. However, issues associated with the passive monitoring role assumed by operators in these systems continue to be of concern. Passive monitoring can lead to a range of human operator performance problems when overseeing automation. The performance cost when human operators are placed in a passive monitoring role has been conceptualized as the out-of-the-loop (OOTL) performance problem: where adding more automation to a system makes it less likely that the operator will notice an automation failure and intervene appropriately (Endsley & Kiris, 1995). The OOTL performance problem has been attributed to numerous factors including vigilance decrements, fatigue, task disengagement, and poor situation awareness. This study tested two different approaches to addressing the OOTL performance problem associated with high degree automation in a simulation of en-route ATC (ATC-labAdvanced; Fothergill, Loft, & Neal, 2009). Following a 60-min training and practice session, 115 university student participants completed two 30-min ATC scenarios; one under manual control and one where they supervised high degree automation (counterbalanced order). The automation performed all acceptances for aircraft entering the sector of controlled airspace, handed off all departing aircraft, and resolved all conflicts between aircraft pairs that would otherwise have violated the minimum safe separation standards (except for a single automation failure event). Participants were instructed that the automation was highly reliable, but not infallible. The first aim was to confirm that while high degree automation can reduce workload, it can also lead to increased task disengagement and fatigue when compared to manual control. Furthermore, to determine how well participants supervised the automation, the conflict detection automation failed once late in the automation scenario. This failure involved two aircraft violating the minimum lateral and vertical separation standard and being missed by the automation. We expected to find that participants would fail to detect this conflict more often, or be slower to detect it, when under automation conditions, compared to a comparable conflict event presented when under manual control. Our second aim was to investigate whether these costs of automation could be ameliorated by techniques designed to improve task engagement. Participants were assigned to one of three automation conditions, including automation with (1) no acknowledgements, (2) acknowledgments, or (3) queries. In the no acknowledgements condition, automation failure monitoring was the only task performed. In the acknowledgements condition, similar to Pop et al. (2012), participants were additionally instructed to click to acknowledge each automated action, thereby potentially improving engagement by adding an active component to an otherwise passive monitoring task. In the queries condition, participants were queried regarding the past, present, and future state of aircraft on the display. The goal was to help participants maintain an accurate mental model (aka. situation awareness) when using automation. We found that automation reduced workload, increased disengagement and fatigue, and impaired detection of a single conflict detection failure event compared to manual task performance. Consistent with previous research, this shows that as a higher degree of automation is added to a system, it becomes less likely that the operator will notice automation failures and intervene appropriately (e.g. Pop et al., 2012). The first intervention tested whether adding automation acknowledgement requirements to the task made it easier for participants to detect and resolve a single automation failure event. The results showed that there was no difference between automation with and without acknowledgement requirements on workload, task disengagement, fatigue, and the detection of the automation failure event. The second intervention tested whether adding queries regarding aircraft on the display would improve failure detection performance. The queries intervention successfully reduced task disengagement and trended towards reducing fatigue, while workload was maintained at a level similar to that of manual control. These findings suggest that the manipulation successfully reduced some of the subjective deficits associated with the passive monitoring of automation. However, there was a significant cost to participants’ ability to detect and resolve the automation failure event relative to manual performance, where half the participants in the queries condition missed the automation failure entirely, compared to 25% in the no queries condition. Response times to detect the failure event were also considerably longer when queries were included compared to no queries. One explanation is that the queries condition may have been engaging to the point of distraction. This is supported by qualitative information provided by participants, where 40% mentioned that they found the queries to be distracting. Future studies may wish to examine the effectiveness of auditory queries instead of visual queries, potentially with verbal instead of typed responses. This may allow queries to reduce task disengagement and fatigue while potentially improving participants’ ability to intervene to automation failures.