Preattentive Processing

Certain visual properties can be rapidly and accurately detected by our massively parallel, low-level visual system. Such visual properties are said to be preattentively processed. A common experiment used to determine if a visual property can be preattentively processed is to measure the response time to find a target in a set of distractors. When a visual property can be preattentively processed, the time taken to detect the target will be relatively independent of the number of distractors because a serial search is not required.

I have put together a preattentive processing demo for conducting such experiments. It has examples of visual properties that are and are not preattentively processed. Note that, at least for myself, some visual properties are preattentively stronger than others (e.g., color vs. small target size). In addition, the demo illustrates that most conjunctions (combinations of visual properties) can not be preattentively processed.


Additional information about preattentive processing can be found on Healy’s Perception in Visualization site and in Ware’s Information Visualization: Perception for Design textbook.

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