C. Melody Carswell

THE PROXIMITY COMPATIBILITY PRINCIPLE: ITS PSYCHOLOGICAL FOUNDATION AND RELEVANCE TO DISPLAY DESIGN

In this report we describe the concept of the proximity compatibility principle (PCP) and demonstrate its relevance to display design: Displays relevant to a common task or mental operation (close task or mental proximity) should be rendered close together in perceptual space (close display proximity). Different forms of task proximity are discussed, as are the different information-processing mechanisms that underlie the effects of the several different design manipulations of display proximity. Experimental data that support this process-based elaboration of PCP are then reviewed in design contexts relating to aviation, graphs, display layout, and decision aiding.

Information integration and the object display An interaction of task demands and display superiority

Two tasks, varying in their demands to integrate multiple information sources, were used in a comparison of two graphical display formats. One display technique, an ‘object display’, utilized different dimensions of a single perceptual object to display task-relevant information. A contrasting graphical technique, a ‘bar graph’, used the same dimension of several separate objects to present identical information. In one experiment, 24 subjects used both displays to perform a simulated process control task in which integration of information from several time-varying sources was required. In a second experiment, 20 additional subjects used both displays in a non-integration task that required monitoring for particular values of six independent system outputs. Results of the integration experiment revealed that performance was superior when the object display was used. However, when the non-integration task was studied, the bar graphs provided more efficient performance. Thus, the requirement to integrate i...

Assessing Mental Workload During Laparoscopic Surgery

Although the use of performance efficiency measures (speed, movement economy, errors) and ergonomic assessments are relatively well established, the evaluation of cognitive outcomes is rare. This report makes the case for assessment strategies that include mental workload measures as a way to improve training scenarios and training/operating environments. These mental workload measures can be crucially important in determining the difference between well-intentioned but subtly distracting technologies and true breakthroughs that will enhance performance and reduce stress.

Choosing specifiers: an evaluation of the basic tasks model of graphical perception

Effect sizes obtained from 39 experiments were used to evaluate the predictions of the basic tasks model of graphical efficacy. This model predicts that performance will be attenuated with graphical displays as a function of the particular specifier, or visual dimension, used to code data values. In this review the basic tasks model predicted performance more accurately than did Tuftes data-ink principle. In addition, variability in effect sizes across studies revealed that the model was more successful at predicting performance in local (focusing) tasks than in global information synthesis tasks. Furthermore, the model was better at predicting performance in tasks requiring the use of physically present rather than remembered graphs. Further differences in effect sizes resulted from variability in the exact specifiers used in experimental graphs. Minimal differences were obtained among graphs that used position, length, or angle as specifiers. However, graphs that used area or volume to represent quantitative values were associated with consistently worse performance than found with other formats.

Guidelines for Presenting Quantitative Data in HFES Publications

This article provides guidelines for presenting quantitative data in papers for publication. The article begins with a reader-centered design philosophy that distills the maxim “know thy user” into three components: (a) know your users′ tasks, (b) know the operations supported by your displays, and (c) match users operations to the ones supported by your display. Next, factors affecting the decision to present data in text, tables, or graphs are described: the amount of data, the readers′ informational needs, and the value of visualizing the data. The remainder of the article outlines the design decisions required once an author has selected graphs as the data presentation medium. Decisions about the type of graph depend on the readers′ experience and informational needs as well as characteristics of the independent (predictor) variables and the dependent (criterion) variable. Finally, specific guidelines for the design of graphs are presented. The guidelines were derived from empirical studies, analyses of graph readers′ tasks, and practice-based design guidelines. The guidelines focus on matching the specific sensory, perceptual, and cognitive operations required to read a graph to the operations that the graph supports.

The perceptual interaction of graphical attributes: Configurality, stimulus homogeneity, and object integration

Researchers have proposed that graphical efficacy may be determined, in part, by the nature of the perceptual interactions that exist between attributes used to create graphical displays. One extreme type of interaction isintegrality, in which two or more physical dimensions are represented as a single psychological dimension in the observer. An alternative type of interaction isconfigurality, in which a global emergent dimension is availableto the observer in addition to the component attributes. Thirteen stimulus sets, each composed of attributes commonly used in the design of graphs, were submitted to the performance-based diagnostics of integrality and configurality. Analyses suggest a continuum of configurality among the present stimulus sets, with little evidence for integral graphical attributes. The configural pattern of results was more common when two identical dimensions were paired (homogeneous stimuli) than when two different dimensions were paired (heterogeneous stimuli). However, there was no evidence that pairs of dimensions belonging to a single object (object integration) were any more configural than dimensions belonging to different objects. Object integration was, however, consistently related to inefficient performance in tasks requiring the filtering of one of two component dimensions.

Mixing and Matching Lower-Level Codes for Object Displays: Evidence for Two Sources of Proximity Compatibility

The proximity compatibility principle (PCP) proposes that visually unitary configurations of data values, such as object displays, will support information integration better than will more separable formats. In the present study formats were created by either mixing or matching pairs of lower-level codes (i.e., linear extent, angle, and color). Performance with object and separable configurations of these codes was compared for two integration tasks: system state classifications requiring either (1) comparisons of values or (2) identification of conjunctions of values. Object displays formed with matched codes were more likely to facilitate comparisons, whereas object displays formed from mixed codes were more likely to facilitate conjunction identification. These data suggest that two mechanisms may underlie object display advantages for integration-one based on relational properties or emergent features and one based on the efficient processing of the lowerlevel codes themselves .

Emergency management information systems: Could decision makers be supported in choosing display formats?

Recent information technologies make it possible to include sophisticated three-dimensional display formats in emergency management information systems (EMIS), decision-support systems that facilitate decision making in crisis situations. However, if decision makers are to improve their decisional performance, they must correctly identify appropriate situations for using these formats. We conduct two experiments and find that, as prior research has suggested, decision makers do not choose the most appropriate display format, but their performance improves when given prospective decisional guidance. We discuss implications of these findings for EMIS design, for the training of emergency management professionals, and for future research on display formats and decisional guidance.

16 Reading Graphs: Interactions of Processing Requirements and Stimulus Structure

Publisher Summary The emphasis on structural variables alone is insufficient to account for many aspects of graphical communication, even those associated with variations in the efficacy of different graphical formats. One of the most common findings in the field of comparative graphics is that the efficacy of any graphical format is highly task dependent. Attention must not only be devoted to the structural characteristics of graphical displays but also to the processing demands of the tasks that the graphs subserve. The chapter traces the history of comparative graphics within the framework of this structure-process or display-task distinction. The chapter reviews the reports of experiments in which display variables, task variables, or both are manipulated by the investigators and focuses on the gradual refinement of the structural concepts used to distinguish graphical formats, as well as on the growing interest in the processing demands of graphical tasks. The chapter also discusses the proximity–compatibility hypothesis, a framework developed specifically in response to the need to understand structure-process interactions in the reading of graphs.

Endoscopic Video Texture Mapping on Pre-Built 3-D Anatomical Objects Without Camera Tracking

Traditional minimally invasive surgeries use a view port provided by an endoscope or laparoscope. We argue that a useful addition to typical endoscopic imagery would be a global 3-D view providing a wider field of view with explicit depth information for both the exterior and interior of target anatomy. One technical challenge of implementing such a view is finding efficient and accurate means of registering texture images from the laparoscope on prebuilt 3-D surface models of target anatomy derived from magnetic resonance (MR) or computed tomography (CT) images. This paper presents a novel method for addressing this challenge that differs from previous approaches, which depend on tracking the position of the laparoscope. We take advantage of the fact that neighboring frames within a video sequence usually contain enough coherence to allow a 2-D-2-D registration, which is a much more tractable problem. The texturing process can be bootstrapped by an initial 2-D-3-D user-assisted registration of the first video frame followed by mostly-automatic texturing of subsequent frames. We perform experiments on phantom and real data, validate the algorithm against the ground truth, and compare it with the traditional tracking method by simulations. Experiments show that our method improves registration performance compared to the traditional tracking approach.