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The bright yellow dot on the computer screen is stationary as the blue shapes in the background swirl around it. As the viewer continues to stare at the center of the screen, the yellow dot appears to vanish.

In a study published online Sunday in the journal Psychological Science, Yale University researchers Brian Scholl and Joshua J. New offer an explanation for "motion-induced blindness" - a phenomenon in which the mind makes objects in plain sight simply disappear.

Scholl, associate professor of psychology, and New, professor and postdoctoral fellow in the Perception and Cognition Laboratory of the Department of Psychology, say motion-induced blindness is analogous to scotomas, local regions of vision loss associated with several diseases. Many individuals with scotomas do not even realize they have "blind spots," just as all people are unaware of their own blind spot, where the optic nerve exits the eye. In both cases, the brain recognizes that the blank spot in their visual field isn't part of the outside world and simply erases it from consciousness.

In the computer-generated case of motion-induced blindness, the yellow dot does not take part in the surrounding motion, so the brain decides that it must not be part of the outside world and erases it from awareness, the researchers say. To avoid leaving a "hole" floating in space, the brain fills in the missing dot with information taken from the surrounding background, and the dot vanishes.

"We normally think of perception as helping us to recognize objects in the world, but this work shows how the brain also tries to help us by ignoring stimulation that may not be in the world, pretending it doesn't exist," said Scholl.

"If it's all in your head, in other words, it's not worth seeing," New said.

Movies of the effects can be seen at the researchers website: http://www.yale.edu/perception/MIB

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