Using Gaze-contingent Displays in Eye-Movement Research

The technique of gaze-contingent displays can be used
to directly measure parameters of visual attention during
natural tasks, whoch otherwise can only be estimated
indirectly or by rapid stimulus presentation. In a
visual search task with a gaze-contingent window, a
round window is always centered on the subject's current
gaze position. We can show, for example, all information
within the window, and only restricted or no information
outside of it. In three experiments, this technique is
used to investigate the influence of task difficulty,
secondary task performance, and expertise on the visual
span, and also to study the influence of peripheral
information on the central processing in a visual search
task.