Dr. Richards is trying to explain why we are able to see colour afterimages. She should probably explain this by referring to

Question

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The opponent process theory explains how we perceive colors as the result of complex processes involving opposing neural processes for different pairs of colors, which can lead to the experience of color afterimages. This theory suggests that certain colors are linked in the brain in opposing pairs, and when one color in a pair is viewed for an extended period, the opposing color can be seen as an afterimage once the initial color is removed.

Dr Richards Is Trying to Explain Why We Are Able