Motion Extrapolation Into the Blind Spot

Chapter 9 discusses the blind spot, which is an area in the back of the retina that contains no photoreceptors. It is basically part of the eye where no vision or light is reflected into it. Each eye has one and it is also called the optic disc. I was interested in this part of the eye and came across a study by Gerrit W. Maus and Romi Nijhawah. They were measuring areas of the blind spot and what a person can percieve in its boundaries, which is defined in the article as the area encompassed by the blind spot.
The researchers' hypothesis was "the percieved position of the object is extrapolated during continuous motion, therefore it should be seen as disappearing in a position shifted forward past the blind-spot boundary into the blind area." In case you don't know what "extrapolation" means (because I didn't), it means to infer something. So basically an object is inferred, or believed, to exist even though one cannot see it, because its in their blind spot.
Five participants were in this study, an one was the author Maus himself. Only he knew the hypothesis of the study and the other four were uninformed.
Both of the eyes were tested one after the other, using an eye patch over the opposite eye. The participant would look at a black screen with 2 white lines, one in their visual field and the other not in their visual field. The bar in the visual field would move into the blind spot of that eye and start flicking on and off. There were 280 trials on performed on each eye.
In conclusion, the researchers discovered "the visual system predicts the postion of a moving object to overcome neural processing delays inherent in the visual pathway." Basically, the brain infers an object's position as it moves into the blind spot based on past visual information.

Maus, G.W., Nijhawan, R. (2008). Motion extrapolation into the blind spot. Psychological Sciences, 19(11), 1087-1091. doi: 10.1111/j.1467-9280.2008.02205.x

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