Many experiments have shown that the human visual system makes extensive use of contextual information for facilitating object search in natural scenes. However, the question of how to formally model contextual influences is still open. On the basis of a Bayesian framework, the authors present an original approach of attentional guidance by global scene context. The model comprises 2 parallel pathways; one pathway computes local features (saliency) and the other computes global (scenecentered) features. The contextual guidance model of attention combines bottom-up saliency, scene context, and top-down mechanisms at an early stage of visual processing and predicts the image regions likely to be fixated by human observers performing natural search tasks in real-world scenes.

We investigate how users interact with the results page of a WWW search engine using eye-tracking. The goal is to gain insight into how users browse the presented abstracts and how they select links for further exploration. Such understanding is valuable for improved interface design, as well as for more accurate interpretations of implicit feedback (e.g. clickthrough) for machine learning. The following presents initial results, focusing on the amount of time spent viewing the presented abstracts, the total number of abstract viewed, as well as data like query word frequency [6]. Howev tracking, these measurements can at best give in diameter, as a lar measures of how thoroughly searchers evaluate their results set.

We analyzed the coordination between gaze behavior, fingertip movements, and movements of the manipulated object when subjects reached for and grasped a bar and moved it to press a target-switch. Subjects almost exclusively fixated certain landmarks critical for the control of the task. Landmarks at which contact events took place were obligatory gaze targets. These included the grasp site on the bar, the target, and the support surface where the bar was returned after target contact. Any obstacle in the direct movement path and the tip of the bar were optional landmarks. Subjects never fixated the hand or the moving bar. Gaze and hand/bar movements were linked concerning landmarks, with gaze leading. The instant that gaze exited a given landmark coincided with a kinematic event at that landmark in a manner suggesting that subjects monitored critical kinematic events for phasic verification of

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Larger screens and higher resolution enhance the viewing experience by allowing for deeper immersion. Recent research shows that a wider field of view can lead to increased performance in productivity tasks [2]. Over the past years, industry has been addressing the resulting demand by offering displays of steadily increasing resolution, reaching resolutions of over 9 million pixels (IBM T220 display). Although high resolution is desirable for a variety of applications, it results in an ongoing challenge for creators of rendering hardware, as the large number of pixels makes these displays especially hungry for computational resources. Displaying computationally intense graphics, such as flight simulation or interactive scientific visualization requires considerable rendering effort. In many cases, this issue can be addressed with parallel rendering hardware; a display system consisting of an array of projectors, for example, is often driven by an array of PCs or a PC “cluster”. Parallel hardware, however, leads to substantially increased costs and space requirements. Furthermore, in the case of projector arraybased displays, the increased need for rendering hardware is accompanied by the cost of the projector technology. So when people make decisions about display sizes and resolutions, cost and space requirements for rendering hardware and display play an important role.

This monograph discusses research, theory, and practice relevant to how children learn to read English. After an initial overview of writing systems, the discussion summarizes research from developmental psychology on children's language competency when they enter school and on the nature of early reading development. Subsequent sections review theories of learning to read, the characteristics of children who do not learn to read (i.e., who have developmental dyslexia), research from cognitive psychology and cognitive neuroscience on skilled reading, and connectionist models of learning to read. The implications of the research findings for learning to read and teaching reading are discussed. Next, the primary methods used to teach reading (phonics and whole language) are summarized. The final section reviews laboratory and classroom studies on teaching reading. From these different sources of evidence, two inescapable conclusions emerge: (a) Mastering the alphabetic principle (that written symbols are associated with phonemes) is essential to becoming proficient in the skill of reading, and (b) methods that teach this principle directly are more effective than those that do not (especially for children who are at risk in some way for having difficulty learning to read). Using whole-language activities to supplement phonics instruction does help make reading fun and meaningful for children, but ultimately, phonics instruction is critically important because it helps beginning readers understand the alphabetic principle and learn new words. Thus, elementary -school teachers who make the alphabetic principle explicit are most effective in helping their students become skilled, independent readers.

conducted. Forty years of research has assumed that category learning often involves learning to selectively attend to only those stimulus dimensions useful for classification. We confirmed that participants learned to allocate their attention optimally. We also found that learners tend to fixate all stimulus dimensions early in learning. This result obtained despite evidence that participants were also testing one-dimensional rules during this period. Finally, the restriction of eye movements to only relevant dimensions tended to occur only after errors were largely (or completely) eliminated. We interpret these findings as consistent with multiple-systems theories of learning which maximize information input in order to maximize the number of learning modules involved, and which focus solely on relevant information only after one module has solved the learning problem.

We study a new task, proactive information retrieval by combining implicit relevance feedback and collaborative filtering. We have constructed a controlled experimental setting, a prototype application, in which the users try to find interesting scientific articles by browsing their titles. Implicit feedback is inferred from eye movement signals, with discriminative hidden Markov models estimated from existing data in which explicit relevance feedback is available. Collaborative filtering is carried out using the User Rating Profile model, a state-of-the-art probabilistic latent variable model, computed using Markov Chain Monte Carlo techniques. For new document titles the prediction accuracy with eye movements, collaborative filtering, and their combination was significantly better than by chance. The best prediction accuracy still leaves room for improvement but shows that proactive information retrieval and combination of many sources of relevance feedback is feasible.

We describe an algorithm and software for creating variable resolution displays in real time, contingent upon the direction of gaze. The algorithm takes as input a video sequence and an arbitrary, real-valued, two-dimensional map that specifies a desired amount of filtering (blur) at each pixel location relative to direction of gaze. For each input video image the follow operations are performed: (1) the image is coded as a multi-resolution pyramid, (2) the gaze direction is measured, (3) the resolution map is shifted to the gaze direction, (4) the desired filtering at each pixel location is achieved by interpolating between levels of the pyramid using the resolution map, and (5) the interpolated image is displayed. The transfer function associated with each level of the pyramid is calibrated beforehand so that the interpolation produces exactly the desired amount of filtering at each pixel. This algorithm produces precision, artifactfree displays in 8-bit grayscale or 24-bit color. The software can process live or prerecorded video at over 60 frames per second on ordinary personal computers without special hardware. Direction of gaze for each processed video frame may be taken from an eye-tracker, from a sequence of directions saved on disk, or from another pointing device (such as a mouse). The software is demonstrated by simulating the visual fields of normals and of patients with low vision. We are currently using the software to precisely control retinal stimulation during complex tasks such as extended visual search.