Engineering topics

Wickens, Christopher D.

Publications and source records attributed to Wickens, Christopher D..

At least 19 records

NASA NTRS2015

Circadian Effects on Simple Components of Complex Task Performance

The goal of this study was to advance understanding and prediction of the impact of circadian rhythm on aspects of complex task performance during unexpected automation failures, and subsequent fault management. Participants trained on two tasks: a process control simulation, featuring automated support; and a multi-tasking platform. Participants then completed one task in a very early morning (circadian night) session, and the other during a late afternoon (circadian day) session. Small effects of time of day were seen on simple components of task performance, but impacts on more demanding components, such as those that occur following an automation failure, were muted relative to previous studies where circadian rhythm was compounded with sleep deprivation and fatigue. Circadian low participants engaged in compensatory strategies, rather than passively monitoring the automation. The findings and implications are discussed in the context of a model that includes the effects of sleep and fatigue factors.

circadian effects↗

NASA NTRS2015

The Role of Individual Differences in Executive Attentional Networks and Switching Choices in Multi-Task Management

Individual differences in cognitive processing relate to critical performance differences in real-world environments. Task switching is required for many of them and especially for task management during overload. Research exploring individual differences related to switching behavior (both frequency, and adherence to optimal switch times) is, however, sparse. We examined these relationships here, using the attentional network task to index executive control, and an ongoing tracking task (within a larger suite of concurrent task demands) to examine switching behavior. The results failed to support a general relationship between executive control and frequency in a complex, heterogeneous multi-task environment. However, higher executive control participants more successfully exploited optimal switching times, highlighting the varying role of individual differences in task management, when choice is unconstrained.

Gutzwiller, Robert S.↗

NASA NTRS2007

Evaluating the Effects of Dimensionality in Advanced Avionic Display Concepts for Synthetic Vision Systems

Synthetic vision systems provide an in-cockpit view of terrain and other hazards via a computer-generated display representation. Two experiments examined several display concepts for synthetic vision and evaluated how such displays modulate pilot performance. Experiment 1 (24 general aviation pilots) compared three navigational display (ND) concepts: 2D coplanar, 3D, and split-screen. Experiment 2 (12 commercial airline pilots) evaluated baseline 'blue sky/brown ground' or synthetic vision-enabled primary flight displays (PFDs) and three ND concepts: 2D coplanar with and without synthetic vision and a dynamic multi-mode rotatable exocentric format. In general, the results pointed to an overall advantage for a split-screen format, whether it be stand-alone (Experiment 1) or available via rotatable viewpoints (Experiment 2). Furthermore, Experiment 2 revealed benefits associated with utilizing synthetic vision in both the PFD and ND representations and the value of combined ego- and exocentric presentations.

Alexander, Amy L.↗

NASA NTRS2005

Human Performance Models of Pilot Behavior

Five modeling teams from industry and academia were chosen by the NASA Aviation Safety and Security Program to develop human performance models (HPM) of pilots performing taxi operations and runway instrument approaches with and without advanced displays. One representative from each team will serve as a panelist to discuss their team s model architecture, augmentations and advancements to HPMs, and aviation-safety related lessons learned. Panelists will discuss how modeling results are influenced by a model s architecture and structure, the role of the external environment, specific modeling advances and future directions and challenges for human performance modeling in aviation.

Foyle, David C.↗

NASA NTRS2004

3D Navigation and Integrated Hazard Display in Advanced Avionics: Workload, Performance, and Situation Awareness

We examined the ability for pilots to estimate traffic location in an Integrated Hazard Display, and how such estimations should be measured. Twelve pilots viewed static images of traffic scenarios and then estimated the outside world locations of queried traffic represented in one of three display types (2D coplanar, 3D exocentric, and split-screen) and in one of four conditions (display present/blank crossed with outside world present/blank). Overall, the 2D coplanar display best supported both vertical (compared to 3D) and lateral (compared to split-screen) traffic position estimation performance. Costs of the 3D display were associated with perceptual ambiguity. Costs of the split screen display were inferred to result from inappropriate attention allocation. Furthermore, although pilots were faster in estimating traffic locations when relying on memory, accuracy was greatest when the display was available.

Wickens, Christopher D.↗

NASA NTRS2003

The Primary Flight Display and Its Pathway Guidance: Workload, Performance, and Situation Awareness

In two experiments carried out in a high fidelity general aviation flight simulator, 42 instrument rated pilots flew a pathway-in-the-sky (tunnel) display through a series of multi-leg curved stepdown approaches through mountainous terrain. Both experiments examined how properties of the tunnel influenced flight path tracking performance, traffic awareness, terrain awareness and workload (assessed both by subjective and secondary task performance measures). Experiment 1, flown in simulated VMC, compared high and low intensity tunnels, with a less cluttered follow-me-airplane (FMA). The results revealed that both tunnels supported better flight path tracking than the FMA, because of the availability of more preview information. Increasing tunnel intensity, while reducing subjective workload, had no benefit on tracking, and degraded traffic detection performance. In Experiment 2, flown mostly in IMC, the low intensity tunnel was flown with a large (10 inch x 8 inch) and small (8 inch x 6.5 inch) display, representing a geometric field of view (GFOV) of either 30 degrees or 60 degrees. Most measures of flight path tracking performance favored the smaller display, and particularly the 60 degree GFOV, which presented a smaller appearing tunnel, and a wider range of terrain depiction. The larger GFOV also supported better terrain awareness, and yielded a lower secondary task assessment of workload. In both experiments, the final landing approach was terminated by a runway obstruction, and the tunnel guided pilots on a missed approach. In nearly all cases, pilots failed to notice an air hazard that lay in the missed approach path, but was only depicted in the outside view.

Wickens, Christopher D.↗

NASA NTRS1997

Cockpit Displays to Support Hazard Awareness in Free Flight

Three experiments are described which each examine different aspects of the formatting and integration of cockpit displays of traffic information to support pilots in traffic avoidance planning. The first two experiments compared two-dimensional (coplanar) with three-dimensional (perspective) versions of a cockpit display of traffic information. In Experiment 1, 30 certified flight instructors flew a series of traffic conflict detection and avoidance maneuvers around an intruder aircraft, sometimes in the presence of a second intruder. The results revealed an advantage for the coplanar display, particularly when there was vertical intruder behavior. In Experiment 2, 17 instructors flew with the coplanar and perspective formats when weather information was either overlaid or displayed separately. Again performance was best with the coplanar display, particularly when the weather data were overlaid. The results of both experiments are also discussed in ten-ns of the traffic maneuver stereotypes exhibited by the pilots. Experiment 3 examined the benefits of the two different predictor elements used in the coplanar displays of Experiments 1 and 2. The study was carried out in a multitask context. These elements were both found to improve safety (reduce actual and predicted conflicts) and to reduce workload, although the different elements affected workload in different ways. Neither predictor element imposed a cost to concurrent task performance.

Wickens, Christopher D.↗

NASA NTRS1997

Predictive Features of a Cockpit Traffic Display: A Workload Assessment

Eighteen pilots flew a series of traffic avoidance maneuvers in an experiment designed to assess the support offered and workload imposed by different levels of traffic display information in a free flight simulation. Three display prototypes were compared which differed in traffic information provided. A BASELINE (BL) display provided current and (2nd order) predicted information regarding ownship and current information of an intruder aircraft, represented on lateral and vertical displays in a coplanar suite. An INTRUDER PREDICTOR (IP) display, augmented the baseline display by providing lateral and vertical prediction of the intruder aircraft. A THREAT VECTOR (TV) display added to the IP display a vector that indicates the direction from ownship to the intruder at the predicted point of closest contact (POCC). The length of the vector corresponds to the radius of the protected zone, and the distance of the intersection of the vector with ownship predictor, corresponds to the time available till POCC or loss of separation. Pilots time shared the traffic avoidance task with a secondary task requiring them to monitor the top of the display for faint targets. This task simulated the visual demands of out-of-cockpit scanning, and hence was used to estimate the head-down time required by the different display formats. The results revealed that both display augmentations improved performance (safety) as assessed by predicted and actual loss of separation (i.e., penetration of the protected zone). Both enhancements also reduced workload, as assessed by the NASA TLX scale. The intruder predictor display produced these benefits with no substantial impact on the qualitative nature of the avoidance maneuvers that were selected. The threat vector produced the safety benefits by inducing a greater degree of (effective) lateral maneuvering, thus partially offsetting the benefits of reduced workload. The three displays did not differ in terms of their effect on performance of the monitoring task, used to infer head-down time, nor in the extent of vertical or airspeed maneuvering. The results are discussed in terms of their implications for 19 cognitive engineering design features.

Wickens, Christopher D.↗

NASA NTRS1996

Evaluation of Perspective and Coplanar Cockpit Displays of Traffic Information to Support Hazard Awareness in Free Flight

We examined the cockpit display representation of traffic, to support the pilot in tactical planning and conflict avoidance. Such displays may support the "free flight" concept, but can also support greater situation awareness in a non-free flight environment. Two perspective views and a coplanar display were contrasted in scenarios in which pilots needed to navigate around conflicting traffic, either in the absence (low workload) or presence (high workload) of a second intruder aircraft. All three formats were configured with predictive aiding vectors that explicitly represented the predicted point of closest pass, and predicted penetration of an alert zone around ownship. Ten pilots were assigned to each of the display conditions, and each flew a series of 60 conflict maneuvers that varied in their workload and the complexity of the conflict geometry. Results indicated a tendency to choose vertical over lateral maneuvers, a tendency which was amplified with the coplanar display. Vertical maneuvers by the intruder produced an added source of workload. Importantly, the coplanar display supported performance in all measures that was equal to or greater than either of the perspective displays (i.e., fewer predicted and actual conflicts, less extreme maneuvers). Previous studies that have indicated perspective superiority have only contrasted these with UNIplanar displays rather than the coplanar display used here.

Merwin, David H.↗

NASA NTRS1994

Strategic workload management and decision biases in aviation

Thirty pilots flew three simulated landing approaches under conditions of low, medium, and high workload. Workload conditions were created by varying time pressure and external communications requirements. Our interest was in how the pilots strategically managed or adapted to the increasing workload. We independently assessed the pilot's ranking of the priority of different discrete tasks during the approach and landing. Pilots were found to sacrifice some aspects of primary flight control as workload increased. For discrete tasks, increasing workload increased the amount of time in performing the high priority tasks, decreased the time in performing those of lowest priority, and did not affect duration of performance episodes or optimality of scheduling of tasks of any priority level. Individual differences analysis revealed that high-performing subjects scheduled discrete tasks earlier in the flight and shifted more often between different activities.

Raby, Mireille↗

NASA NTRS1993

Attentional tunneling and the head-up display

Twenty instrument-rated flight students flew simulated landing approaches to a realistic graphics generated airport, using either a head-up display (HUD) of instrument landing systems (ILS) instruments or the same display positioned 8.5 deg. head down. Responses to discrete events appearing either on the ground environment or on the instrument display assessed the pilot's ability to switch attention between these domains. Unexpected events also occurred once (per subject) in each domain. The results revealed that flight path control and attention switching to the instrumnet display was better supported by the HUD, while this advantage disappeared for attention switching to the environment, and for detection of unexpected events. The results are discussed in terms of the attention strategies employed in sampling multiple information sources.

Wickens, Christopher D.↗

NASA NTRS1993

Workload management and geographic disorientation in aviation incidents: A review of the ASRS data base

NASA's Aviation Safety Reporting System (ASRS) incident reports are reviewed in two related areas: pilots' failures to appropriately manage tasks, and breakdowns in geographic orientation. Examination of 51 relevant reports on task management breakdowns revealed that altitude busts and inappropriate runway usee were the most frequently reported consequences. Task management breakdowns appeared to occur at all levels of expertise, and prominent causal factors were related to breakdowns in crew communications, over-involvement with the flight management system and, for small (general aviation) aircraft, preoccupation with weather. Analysis of the 83 cases of geographic disorientation suggested that these too occurred at all levels of pilot experience. With regard to causal factors, a majority was related to poor cockpit resource management, in which inattention led to a loss of geographic awareness. Other leading causes were related to poor weather and poor decision making. The potential of the ASRS database for contributing to research and design issues is addressed.

Williams, Henry P.↗

NASA NTRS1992

Compatibility and consistency in display-control systems - Implications for aircraft decision aid design

In this study we contrast display-control movement relations defined in terms of stimulus-response (physical) compatibility with those defined by stimulus-cognitive compatibility, and we relate these findings to the issue of command versus status levels of decision aid support. A second issue addressed is the cost of inconsistency across multiple display-control mappings. Subjects performed a flight control task while responding to one to four analog indicators, formatted as either command or status displays. The results suggest that there is an advantage for the status format when subjects are required to verbally report the state of the indicator(s), but no advantage was found for either format when subjects were required to manually correct the indicated state. The data point to the importance of display-control consistency and suggest that it may even outweigh that of compatibility.

Andre, Anthony D.↗

NASA NTRS1992

Distance and organization in multifunction displays

One approach to organizing information in a multifunction display (MFD) is to place related screens of information closer to each other. This study identified three metrics that could be used to operationalize the concept of distance in an MFD. The proposed distance metrics - navigational (the number of choice points lying between two screens), organizational (the hierarchical structure of the data base), and cognitive (the user's perception of relationships among screens) - were empirically examined by using a simulated, hierarchically arranged, menu-driven MFD in an aviation context. Subjects engaged in two tasks that required them to access different target screens from various starting screens in a 290-screen MFD. The tasks differed in the navigational mechanisms subjects were allowed to use to navigate around the MFD and the relationships between the starting and target screens. The results suggest that the three distance metrics are meaningful within the context of a multifunction display.

Seidler, Karen S.↗

NASA NTRS1992

Use of nontraditional flight displays for the reduction of central visual overload in the cockpit

The use of nontraditional flight displays to reduce visual overload in the cockpit was investigated in a dual-task paradigm. Three flight displays (central, peripheral, and ecological) were used between subjects for the primary tasks, and the type of secondary task (object identification or motion judgment) and the presentation of the location of the task in the visual field (central or peripheral) were manipulated with groups. The two visual-spatial tasks were time-shared to study the possibility of a compatibility mapping between task type and task location. The ecological display was found to allow for the most efficient time-sharing.

Weinstein, Lisa F.↗

NASA NTRS1991

Frames of reference for helicopter electronic maps - The relevance of spatial cognition and componential analysis

Computer-generated map displays for NOE and low-level helicopter flight were formed according to prior research on maps, navigational problem solving, and spatial cognition in large-scale environments. The north-up map emphasized consistency of object location, wheareas, the track-up map emphasized map-terrain congruency. A component analysis indicates that different cognitive components, e.g., orienting and absolute object location, are supported to varying degrees by properties of different frames of reference.

Harwood, Kelly↗

NASA NTRS1991

Display formatting techniques for improving situation awareness in the aircraft cockpit

Possible modifications of primary flight instruments for attitude control and navigation were examined including a display perspective, frames of reference, and the incorporation of directional color to enhance visual momentum. A low-fidelity fixed-wing flight simulation was evaluated. It is concluded that situation awareness measured by flight performance and recovery from disorientation events, was best maintained with the planar outside-in display, whereas color coding improved the performance on the planar inside-out display.

Andre, Anthony D.↗

NASA NTRS1991

Compatibility and consistency in aircrew decision aiding

A group of 32 subjects performed a flight-control task while responding to between one and four analog indicators that were formatted as either command or status-decision aid displays. The results obtained indicate the advantage of the status format when subjects are required to verbally support the state of the indicator(s), in part, because the command format 'bypasses' the representation of the indicator's state from which the command was derived. No advantage is noted for either format in the case where the subjects are required to manually correct the state indicated. The importance of consistency in system-design efforts may exceed that of compatibility.

Andre, Anthony D.↗