Tactical Display for Soldiers Human Factors Considerations (1997) / Chapter Skim
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3 SITUATION AWARENESS
3 SITUATION AWARENESS
Pages 43-64
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From page 43... ...
Although it is beyond our current understanding to specify how much situation awareness is enough, researchers in the area believe that good performance is linked to good situation awareness (Endsley, 1995~. The chapter begins with a discussion of the individual characteristics that affect situation awareness, including perception, attention allocation, working memory, long-term memory stores, goal-directed behavior, and individual differences in relevant abilities.
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From page 44... ...
Global situation awareness needs can be construed to include one's location within a broad geographical area, navigation information such as the relative location of important features, the current location and direction of movement of other units (friendly and enemy) and current commands and directions from headquarters.
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From page 45... ...
The potential for these trade-offs to occur needs to be very closely examined during the design process in order to ensure that adequate situation awareness is provided across all requirements. FACTORS AFFECTING SITUATION AWARENESS Endsley (1988a, 1994, 1995)
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From page 47... ...
The model shows this goal-directed, top-down processing operating in tandem with bottom-up processing, in which highly salient cues activate appropriate goals and mental models. Thus, situation awareness is the result of an ongoing process of alternating between goal-directed processing and data-driven processing based on a theorized link between goals and mental models.
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From page 48... ...
Due to the limited ability to perceive and process information, significant difficulties may be encountered unless stringent measures are taken to integrate multiple sources of information, reduce extraneous information, simplify the format of information presentation, and integrate the presentation of information with the soldier's tasks. Long-Term Memory Stores Long-term memory stores in the form of mental models or schema are hypothesized to play a major role in dealing with the limitations of attention and working memory.
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From page 49... ...
On the basis of the model presented here, several factors have been hypothesized to be important determinants of variability among individuals in terms of situation awareness capability: (1) spatial abilities, the degree to which one can mentally visualize and manipulate objects and also visualize one's own orientation relative to those objects, (2)
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From page 50... ...
It may be possible to select individuals with better situation awareness capabilities for tasks that involve the new proposed technologies, or to better train them to avoid problems and use effective situation awareness skills, if such skills can be identified. Task and System Factors In addition to individual factors, many features of the environment may affect the soldier's awareness.
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From page 51... ...
Although electronic information systems represent a way of productively increasing workload (and information) during periods of low workload, it is critical that this not occur at the expense of maintaining vigilance regarding the immediate environment.
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From page 52... ...
Stressors Several types of stressors in the combat environment may affect situation awareness, including physical stressors noise, vibration, heat or cold, lighting, atmospheric conditions, boredom or fatigue, cyclical changes and social/psychological stressors fear or anxiety, uncertainty, the importance or consequences of events, self-esteem, career advancement, mental load, and time pressure (Hockey, 1986; Sharit end Salvendy, 1982~. A certain amount of stress may actually improve performance by increasing attention to important aspects of the situation.
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From page 53... ...
To a certain degree, the impact of stressors on situation awareness is a given part of the combat environment. Many new proposed technologies can exacerbate these effects, however, if they interfere with scanning of relevant information in the environment, load working memory, or encourage dependence on highly perceptually salient technological information sources.
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From page 54... ...
On the other hand, the helmet-mounted displays and night vision system may reduce local situation awareness by drawing the soldier's attention away from the immediate environment and into the virtual one or by inducing certain misperceptions regarding the actual location (distance) of objects.
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From page 55... ...
Real-time simulations employing the helmet-mounted display can be used to assess the impact of the system by carefully measuring soldier performance, workload, and situation awareness. Direct measurement of situation awareness during design testing is recommended to provide sufficient insight into potential costs and benefits of design concepts for soldiers' situation awareness, allowing a determination of the degree to which the design successfully addresses the issues we have discussed.
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From page 56... ...
If situation awareness is measured directly, it will be possible to select concepts that promote it increasing the probability that soldiers will make effective decisions and avoid poor ones. Problems with situation awareness, frequently brought on by data overload, nonintegrated data, automation, complex systems that are poorly understood, excess attention demands, and many other factors can be detected early in the design process and corrective changes made to improve the design.
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From page 57... ...
It may indicate the relative priority of different types of information or the relative utility of information sources. In general, however, process measures provide only an indirect indication of operator situation awareness.
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From page 58... ...
Skills · Information management · Communications · Subsystems operations · Instrument scan patterns Knowledge · Mental models -Prototypical schema -Critical cues · Goals · Preconceptions and expectancies Abilities · Spatial · Attention · Memory · Perceptual · Cognitive TasWMission Performance J Decisions ~ ~ L Situation Awareness a ;,vS.Lem .
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From page 59... ...
used a modified version of the subjective workload dominance (SWORD) technique to obtain subjective evaluations of the situation awareness provided by displays.
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From page 60... ...
Subject perceptions are then compared with the real situation based on simulation computer databases to provide an objective measure of situation awareness. The collection of data in this manner provides an objective, unbiased assessment of situation awareness that overcomes the problems incurred when collecting data after the fact, yet minimizes biasing due to secondary task loading or artificially cueing the subject's attention.
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From page 61... ...
. As a global measure, SAGAT includes queries about all operator situation awareness requirements, including Level 1 (perception of data)
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From page 62... ...
CONCLUSIONS A major purpose of the Land Warrior System is to improve the infantry soldier's situation awareness, which in turn is anticipated to improve his performance. There is some evidence that mission performance correlates with situation awareness in aircraft simulators.
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From page 63... ...
4. Hand-held or wrist-mounted displays should be seriously considered as an alternative to the helmet-mounted displays in order to reduce the likelihood of negatively affecting the soldier's local situation awareness.
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From page 64... ...
7. The display design should allow for easy sharing of information between team members and between the field and headquarters.
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