Finding a particular object in a display is important for viewers in many visualizations, for example, when reacting to brushing or to a highlighted object. This can be enabled by making the target object different in one of the visual variables that determine the object's appearance; for example, by changing its color or size. Certain interpretations of the visual search literature have promoted the view that using visual variables such as hue-often labeled as preattentive-would make the target object automatically "popout," implying that an object can be located almost instantly, regardless of the number of objects in the display. In this paper we present a study that serves as a bridge between the extensive visual search literature and visualization, establishing empirical base measurements for the localization task. By testing displays with up to hundreds of objects, we are able to show that none of the common visual variables is immune to the increase in the number of objects. We also provide the first empirically informed comparisons between visual variables for this task in the context of visualization, and show how different visual variables have varying robustness with respect to two additional dimensions: the location of the target and the overall visual arrangement (layout). A free copy of this paper and all supplemental materials are available on our online repository: https://osf.io/z68ak/overview.

翻译：在众多可视化场景中，观众寻找显示画面中的特定对象至关重要，例如在响应刷选操作或高亮显示对象时。这可通过使目标对象在决定其外观的某一视觉变量上区别于其他对象来实现，例如改变其颜色或尺寸。视觉搜索文献中的某些解读曾提出一种观点：使用色调等常被称为"前注意"的视觉变量会使目标对象自动"弹出"，这意味着无论显示画面中存在多少对象，该对象几乎都能被瞬间定位。本文通过一项研究，在广泛的视觉搜索文献与可视化实践之间搭建桥梁，为定位任务建立实证基准测量。通过测试包含多达数百个对象的显示画面，我们证明所有常见视觉变量均无法避免对象数量增加带来的影响。我们首次在可视化背景下为该任务提供了基于实证的视觉变量比较，并展示了不同视觉变量在目标位置和整体视觉布局这两个附加维度上具有差异化的鲁棒性。本文及所有补充材料的免费副本可在我们的在线存储库获取：https://osf.io/z68ak/overview。