Review of Perception of Afterimages

Document Type

Student Presentation

Presentation Date

April 2017

Faculty Sponsor

Brian Stone


The understanding of after images is continually growing. So much so that afterimages have been split into two categories, positive and negative afterimages.

We focused on positive afterimages as it is the less understood of the two. Positive afterimages are very brief, usually lasting about a second or less and occur where there is a bright light then you look to a darker area and you still see the afterimage of what you were looking at. We had participants sit in the dark for 10 minutes initially, followed by a flash of light while looking between two wooden blocks where they then see the after image of the two blocks. These after images are not well understood but it is believed that the brain continues to have photoreceptor cell activity by sending neural impulses to the occipital lobe.

The purpose of this study is to attain a better understanding of positive afterimages and to ask, then answer the question: When you are in the dark and you move one object in front of another, how is that represented in your brain, and will that top-down representation override the visual afterimage perception.

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