This demonstration flashes up an image, and then flashes up the same image with one change in it. This cycling of the two images continues indefinitely. Can you see what is different between the two images? If it takes you a long time, don't worry. It takes most people a long time. Notice that once you find the change, you can't help but see it every time the images flash. This demonstration suggests that our Visual Intelligence can only detect changes in those parts of the image to which we explicitly attend. Do we construct detailed representations of the visual world in areas to which we do not attend? This question is as yet unanswered, but is the subject of current research.
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