Brian D. Fisher

Multiple parallel access in visual attention.

It is widely accepted that there exists a region or locus of maximal resource allocation in visual perception--sometimes referred to as the spotlight of attention. We have argued that even if there is a single locus of processing, there must be multiple loci of parallel access--several places in the visual field must be indexed at once and these indexes can be used to determine where attention is allocated. We have carried out a variety of studies to support these ideas, including experiments showing that subjects can track multiple independent moving targets in a field of identical distractors, that the enhanced ability to detect changes occurring on these targets does not accrue to nontargets nor to items lying inside the convex polygon that they form (so that a zoom-lens of attention does not fit the data). We have used a visual search paradigm to show that (serial or parallel) search can be confined to a subset of indexed items and the layout of these items is of little importance. We have also studied the phenomenon known as subitizing and have shown that subitizing occurs only when items can be preattentively individuated and in those cases location precuing has little effect, compared with when counting occurs, which suggests that subitizing may be carried out by counting active indexes rather than items in the visual field. And finally we have run studies showing that a certain motion effect that is sensitive to attention can occur at multiple precued loci. We believe that this evidence suggests that there is an early preattentive stage in vision where a small number of salient items in the visual field are indexed and thereby made readily accessible for a variety of visual tasks.

Towards understanding IT security professionals and their tools

We report preliminary results of our ongoing field study of IT professionals who are involved in security management. We interviewed a dozen practitioners from five organizations to understand their workplace and tools. We analyzed the interviews using a variation of Grounded Theory and predesigned themes. Our results suggest that the job of IT security management is distributed across multiple employees, often affiliated with different organizational units or groups within a unit and responsible for different aspects of it. The workplace of our participants can be characterized by their responsibilities, goals, tasks, and skills. Three skills stand out as significant in the IT security management workplace: inferential analysis, pattern recognition, and bricolage.

Evidence against a speed limit in multiple-object tracking

Everyday tasks often require us to keep track of multiple objects in dynamic scenes. Past studies show that tracking becomes more difficult as objects move faster. In the present study, we show that this trade-off may not be due to increased speed itself but may, instead, be due to the increased crowding that usually accompanies increases in speed. Here, we isolate changes in speed from variations in crowding, by projecting a tracking display either onto a small area at the center of a hemispheric projection dome or onto the entire dome. Use of the larger display increased retinal image size and object speed by a factor of 4 but did not increase interobject crowding. Results showed that tracking accuracy was equally good in the large-display condition, even when the objects traveled far into the visual periphery. Accuracy was also not reduced when we tested object speeds that limited performance in the small-display condition. These results, along with a reinterpretation of past studies, suggest that we might be able to track multiple moving objects as fast as we can a single moving object, once the effect of object crowding is eliminated.

Visual analytics for complex concepts using a human cognition model

As the information being visualized and the process of understanding that information both become increasingly complex, it is necessary to develop new visualization approaches that facilitate the flow of human reasoning. In this paper, we endeavor to push visualization design a step beyond current user models by discussing a modeling framework of human ldquohigher cognition.rdquo Based on this cognition model, we present design guidelines for the development of visual interfaces designed to maximize the complementary cognitive strengths of both human and computer. Some of these principles are already being reflected in the better visual analytics designs, while others have not yet been applied or fully applied. But none of the guidelines have explained the deeper rationale that the model provides. Lastly, we discuss and assess these visual analytics guidelines through the evaluation of several visualization examples.

Flicker distorts visual space constancy.

Effects of flicker on space perception were measured by displacing a flickering target during saccadic eye movements. A small target was flickered at 33, 66, 130 or 260 Hz. Using a 2-interval forced-choice design, sensitivity to the displacement was about twice as great when the target was moved in the direction opposite the eye movement as when it was moved in the same direction. This would be expected from a partial breakdown of space constancy--the world should seem to jump in the direction opposite an eye movement. Even if a suppression of displacement detection during saccades prevents this jump from being perceived; it should be easier to detect a target displacement in the direction opposite the eye movement than in the same direction: when movement is opposite, the imposed displacement adds to the illusory displacement, making detection easier. Displacements were more easily detected at lower flicker rates. Results imply that both masking and extraretinal signals are important in suppressing the detectability of target displacements during saccades, and that flicker on video display terminals may distort space perception.

Saccadic Suppression of Displacement is Strongest in Central Vision

Perception of target displacement is severely degraded if the displacement occurs during a saccadic eye movement, but the variation of this effect across the visual field is unknown. A small target was displaced from a starting point at the midline, or 10 deg to the right or left, while the eye made a saccade from the 10 deg right position to the 10 deg left position. Saccades were detected and the target displaced on line. Assessed with a signal detection measure, suppression was stronger in central vision than in more peripheral locations for all three subjects. Leftward and rightward displacements yielded equal thresholds. The results complement the findings of others to reveal a picture of perceptual events during saccades, with both deeper saccadic suppression and faster correction of spatial values (the correspondences between retinal position and perceived egocentric direction), favouring more accurate spatial processing in central vision than in the periphery.

Towards the Personal Equation of Interaction: The impact of personality factors on visual analytics interface interaction

These current studies explored the impact of individual differences in personality factors on interface interaction and learning performance behaviors in both an interactive visualization and a menu-driven web table in two studies. Participants were administered 3 psychometric measures designed to assess Locus of Control, Extraversion, and Neuroticism. Participants were then asked to complete multiple procedural learning tasks in each interface. Results demonstrated that all three measures predicted completion times. Additionally, results analyses demonstrated personality factors also predicted the number of insights participants reported while completing the tasks in each interface. We discuss how these findings advance our ongoing research in the Personal Equation of Interaction.

Comparing cursor orientations for mouse, pointer, and pen interaction

Most graphical user interfaces provide visual cursors to facilitate interaction with input devices such as mice, pointers, and pens. These cursors often include directional cues that could influence the stimulus-response compatibility of user input. We conducted a controlled evaluation of four cursor orientations and an orientation-neutral cursor in a circular menu selection task. Mouse interaction on a desktop, pointer (i.e. wand) interaction on a large screen, and pen interaction on a Tablet PC were evaluated. Our results suggest that choosing appropriate cursors is especially important for pointer interaction, but may be less important for mice or pens. Cursors oriented toward the lower-right corner of a display yielded the poorest performance overall while orientation-neutral cursors were generally the best. Advantages were found for orientations aligned with the direction of movement. We discuss these results and suggest guidelines for the appropriate use of cursors in various input and display configurations.

Comparing CAVE, wall, and desktop displays for navigation and wayfinding in complex 3D models

Computer-aided design (CAD) and 3D visualization techniques are at the heart of many engineering processes such as aircraft, ship, and automobile design. These visualization tasks require users to navigate or wayfind through complex 3D geometric models consisting of millions of parts. Despite numerous studies, it remains unclear whether large-screen displays improve user performance for such activities. We present a user study comparing standard desktop, immersive room (i.e., CAVE), and wall displays with 3D stereo/head-tracking, and mono/no head-tracking. We observed individual differences between users and found that the presence of contextual structure greatly impacted performance, suggesting that providing structure and developing interaction techniques accommodating a wide range of users yields better performance than focusing on display characteristics alone

Science of analytical reasoning

There has been progress in the science of analytical reasoning and in meeting the recommendations for future research that were laid out when the field of visual analytics was established. Researchers have also developed a group of visual analytics tools and methods that embody visual analytics principles and attack important and challenging real-world problems. However, these efforts are only the beginning and much study remains to be done. This article examines the state of the art in visual analytics methods and reasoning and gives examples of current tools and capabilities. It shows that the science of visual analytics needs interdisciplinary efforts, indicates some of the disciplines that should be involved and presents an approach to how they might work together. Finally, the article describes some gaps, opportunities and future directions in developing new theories and models that can be enacted in methods and design principles and applied to significant and complex practical problems and data.