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An afterimage is a visual sensation that persists after the original stimulus has been removed. A common example is seeing a spot of light after briefly looking at the sun and then turning away. When the stimulus involves color, the opponent-process theory explains the occurrence of a negative afterimage, where one perceives the opposing color from the pair (e.g., seeing green after staring at red).

Afterimage

A visual test for negative afterimages uses an illustration of a specific flag. This flag has a green field and a yellow cross, which is bordered by black lines. The intersection of the cross is located slightly to the left of the flag's center, and a small white dot is placed at this intersection to serve as a focal point. This arrangement is designed to demonstrate the opponent-process theory; after staring at the dot for a period and then looking at a neutral surface, a person will typically see a negative afterimage with the opponent colors (a red flag with a blue cross).

Example of a Negative Afterimage Test

An individual stares at a large, bright red square for 45 seconds without moving their eyes. They then immediately look at a plain white wall. Which of the following outcomes is most likely, and what is the best explanation for it?

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