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An eye tracking study was conducted to evaluate specific design features for a prototype web portal application. This software serves independent web content through separate, rectangular, user-modifiable portlets on a web page.Each of seven participants navigated across multiple web pages while conducting six specific tasks, such as removing a link from a portlet. Specific experimental questions included (1) whether eye tracking-derived parameters were related to page sequence or user actions preceding page visits, (2) whether users were biased to traveling vertically or horizontally while viewing a web page, and (3) whether specific sub-features of portlets were visited in any particular order_ Participants required 2-15 screens, and from 7-360+ seconds to complete each task. Based on analysis of screen sequences, there was little evidence that search became more directed as screen sequence increased.Navigation among portlets, when at least two columns exist, was biased towards horizontal search (across columns) as opposed to vertical search (within column). Within a portlet, the header bar was not reliably visited prior to the portlet's body, evidence that header bars are not reliably used for navigation cues.Initial design recommendations emphasized the need to place critical portlets on the left and top of the web portal area, and that related portlets do not need to appear in the same column. Further experimental replications are recommended to geueralize these results to other applications.

Mental workload is known to reduce the area of one's visual field, but little is known about its effects on the shape of the visual field. Considering this, the visual fields of 13 subjects were measured concurrently under three levels of mental workload using a Goldmann visual perimeter. Tone counting tasks were employed to induce mental workload, avoiding interference with visual performance. Various methods of shape measurement and analysis were used to investigate the variation of the shape of the visual field as a function of mental load. As expected, the mean area of visual fields reduced to 92.2% in the medium workload condition and to 86.41% under heavy workload, compared to light load condition. This tunnelling effect was not uniform, but resulted in statistically significant shape distortion as well, as measured by the majority of the 12 shape indices used here. These results have visual performance implications in many tasks that are susceptible to changes in visual fields and peripheral vision. Knowledge of the dynamics of the visual field as a function of mental workload can offer significant advantages also in mathematical modelling of visual search.

Using an eye-tracking methodology, we evaluated food nutrition labels' ability to support rapid and accurate visual search for nutrition information. Participants (5 practiced label readers and 5 nonreaders) viewed 180 trials of nutrition labels on a computer, finding answers to questions (e.g., serving size). Label manipulations included several alternative line arrangements, location of the question target item, and label size. Dependent measures included search time and number of fixations prior to visually capturing the target, as well as the accuracy and duration of the capturing fixation. Practiced label readers acquired the target more quickly and accurately than did less-practiced readers. Targets near the denser center of the label required 33% more time and were harder to find than targets at the top or bottom of the label. Thinner alignment lines were more influential than thicker anchoring lines on visual search time. Overall, the current nutrition label supported accurate and rapid search for desired information. Potential applications of the present methodology include the evaluation of warning labels and other static visual displays.