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Navigation is a basic skill for all humans (Ishikawa, Fujiwara, Imai & Okabe, 2008; Wolbers & Hegarty, 2010; Young, Stanton, Walker, Jenkins, & Smart, 2008). At the same time, it is a demanding task which often is performed in combination with other tasks, for example driving, which require constant attention of the surroundings. Navigation in a stressful and dangerous situation (forest fire, natural disaster or war) is especially challenging. When moving in a challenging environment, it is of uttermost importance to be able to keep track of the current location as well as the direction towards the goal. Also, the person navigating may be occupied with other attention demanding tasks such as searching the surroundings for threats, operating complicated equipment, etc. Often, both hands are occupied either by carrying or operating equipment. To use a map and compass in circumstances like the ones described above are both time-consuming and demands cognitive resources. This could force field personnel to focus too much on the navigation task. For such scenarios a system that can keep track of the current location and facilitate navigation is desirable. In this study we have supplied navigators in a stressful dynamic situation with continuously updated heading and distance information in order to see if their workload could be reduced and performance increased in comparison to when navigating with only a hand-held GPS-device.
GPS-based systems are commonly used for navigation, but the introduction of such support can both have positive and negative effects in terms of workload, behavior, and performance (Young et al., 2008). The question is how to present navigational information and what kind of information that is needed? Although navigational information must be continuously updated (at least while moving), it must be presented in a non-intrusive way, minimizing “inattentional blindness” (Krupenia & Sanderson, 2006). Inattentional blindness refers to a phenomenon that can occur when information is presented to a person performing an attention-demanding task. The study by Krupenia & Sanderson (2006) showed that there is a risk that persons may lose attention in critical situations when information is presented too distant from the actual task at hand or in such a way that it demands a change of focus of attention to be interpreted, thus creating potentially dangerous events. Different placements and types of displays that can present navigational information have been investigated, although no general conclusions can be drawn (see for example Ashbrook, Clawson, Lyons, Patel & Starner, 2008; Bos & Tack, 2005). Hörberg, Gustavsson and Sandberg (2010) have performed a series of experiments based on the concept of presenting heading and distance to upcoming waypoints using a small head-mounted display (HMD) located in the proximity of the eye. The approach in those experiments, and the approach of the authors of this paper, was to investigate the minimal required information that is needed for navigation, and in what kind of media it should be presented. The use of a HMD has been considered as a promising method to present information. Since it is small and can be placed in a flexible way close to the eye, it should not be too intrusive (Figure 1).
Figure 1. A head-mounted display mounted on a pair of glasses