Usability Questionnaire Results - Institute of Aviation - University of ...

likely to have emergent features than separated displays. Emergent features allow for enhancedperformance because they have the ability to exchange perceptual cues for cognitive processing(Sanderson, Flach, Buttigieg, & Casey, 1989; Buttigieg & Sanderson, 1991; Bennett & Flach,1992; Vicente & Rasmussen, 1992). Instead of having to integrate information mentally aboutvarious sources of information, the emergent feature in essence does the cognitive processingperceptually and therefore more automatically. It is no longer necessary to perform morecomplex mental operations after examining multiple information sources. Instead, theperception of an emergent feature is all that needed since it represents the conclusion of all thecomplex mental operations that would have been performed.A classic example of an emergent feature can be seen with bar graphs. If three bar graphsare placed next to each other and have the same height when a “normal” state is occurring, animaginary line can be made across the top of the bar graphs. If some type of system changeoccurs and one bar graph’s height increases, the imaginary line connecting the tops of the bargraphs is no longer straight (Sanderson et al., 1989). This can be considered an emergent featuresince a person monitoring the graphs would be looking for any change in the imaginary line todetect problems.One example of an object displays depicts how emergent features can be made torepresent certain states of a system. Woods, Wise, and Hanes (1981) studied a display for anuclear power reactor that represented eight important parameters whose measures wereindicated by the length of spokes extending from the center of the display. The ends of eachspoke were connected to the next closest, thereby forming a polygon. This display providedemergent features in the shape of the polygon. In fact, specific system states and problems couldbe determined just by looking at the shape of the polygon. This supports both the detection offaults and especially diagnosing problems. Certain shapes of the polygon could be indicative ofspecific underlying problems. This understanding could be made through perception of theshape instead of through cognitive reasoning.Emergent features provide an additional useful source of information that is able to “popout” at the user. This is commonly called the salience of an emergent feature. The ability tohave such high salience accounts for part of the benefits in performance attributed to emergentfeatures that substitute perceptual processing for cognitive processing (Wickens & Carswell,1995). This can be quite beneficial when a task or process can be creatively mapped to a displayand utilizes an emergent feature.2.2.2.3 Configural DisplaysConfigural displays are a display format that involves the mapping of several individualvariables into a single geometrical that changes shape dynamically as a function of changes inthe individual variables (Bennett, Payne, Calcaterra, & Nittoli, 2000). Configural displays aredesigned to represent high-level constraints of a system through the relationships that existamong the low-level data that define the constraint (Bennett, Toms, & Woods, 1993).Configural displays are similar to object displays, but a key difference between the twodisplay formats is that configural displays are spatially laid out so that they will always producean emergent feature whereas object displays may or may not have emergent features.11