This study examines the effectiveness of four techniques to assist scientists in evaluating multidimensional data. Subjects viewed a series of complex 3D data sets, each representing an underlying complex surface, from which a set of discrete points or observations were sampled. From each sample they answered questions that required focus of attention on certain data points or integration across varying numbers of data points and dimensions. After a number of samples were viewed from each surface, subjects were tested for their retention of the surface characteristics. In Experiment 1, 3D (perspective) representations were found to support superior performance to 2D (planar) representations, but only for more integrative questions. Animated motion provided no benefits. In Experiment 2, stereoptic views of a 3D display were also found to support performance, particularly for integrative questions, but the ability to rotate the data space (motion parallax) and the presence of a mesh surface connecting the points did not. The posttests revealed some evidence that 3D representations improved the ability to visualize the surface, but neither 3D renderings nor stereopsis led to a better abstract representation of the data.

In 3 experiments, we examined maneuver choice, flight safety, and mental workload across 3-dimensional (3D) perspective and 2-dimensional coplanar cockpit displays of traffic information in a free-flight simulation. In Experiment 1 (30 pilots), we examined dimensionality issues; in Experiments 2 and 3 (18 pilots each), we examined the effects of traffic density, dimensionality, and vertical profile orientation. Collectively, these data may be modeled by trade-offs between the display types: The coplanar suite suffers from scanning-related integration that increases with conflict density; the 3D display suffers from perceptual ambiguity. This research informs our understanding of how displays modulate performance in free-flight environments.

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The use of various dimensions of color to encode continuous data has become commonplace with the advent of sophisticated computing hardware and software. Applications users can choose from a variety of color pallets as well as create their own for viewing digitized data sets. A primary HCI question emerging from this expanded availability of color for data display is how best to map color dimensions to data dimensions for various applications. The current study examined a subset of the perceptual/cognitive processes underlying pattern recognition tasks, whose efficacy could be affected by the nature the color scale used to visualize the data being viewed. Three types of observers' judgments were examined: absolute discrimination of a value; relative judgment of the difference between two values; and a rank order judgment of 4 values. These values were expressed in the color of a specific region in images displayed using eight different color and gray scales. Preference ratings were collected for the color scales. Grey scales were best for rank ordering tasks, while a blue-green-yellow scale proved superior for an absolute independent task. Scale preferences did not necessarily agree with performance. Implications of the findings and future research are discussed.

A study was performed to determine the extent to which flight-relevant information on instruments peripheral to fixation is extracted and used during fixed-wing instrument flight. Twenty student and twenty instructor pilots flew a series of missions in a fixedwing flight simulator which was interfaced with an eye-tracker. In one mission flightrelevant information was removed from instruments peripheral to fixation while in the other mission peripheral information was intact. Pilots' performance was degraded and eye scan strategies were modified when peripheral information was removed. Furthermore, in several situations instructor pilots' performance was more adversely influenced by the removal of peripheral information than was student pilots' performance. The data are discussed in terms of attentional strategies during flight.