When you’re done with your dot picture, hold it at arm’s length. If the dot picture is of a familiar object, it should be easily recognizable at this distance. See if other people can identify the object in the picture.
For simplicity, we’ve used a picture of an eye as a sample here. Unfamiliar or complicated objects may be more difficult to recognize at close range.
Place the picture across the room, and you’ll notice that it becomes much easier to recognize. The dots will seem to disappear, with only the pattern remaining. The picture may appear slightly fuzzy, but it certainly doesn’t appear to be made of dots!
Pictures made of dots are easily recognized by the brain because the brain is always attempting to interpret what it sees. Even though our sample picture is made up of different-sized dots, the brain recognizes the overall shape as that of an eye, since it is very familiar with that shape. This is the same reason you may see shapes in clouds, inkblots, or even pieces of toast. Your brain does not merely register these shapes as abstract patterns, it attempts to interpret them based on previous experience.
The dots disappear when you view the picture from a distance because of the limited resolving power of your eyes. You see the dot picture because light reflecting from the page makes an image on the retina of your eye. This image stimulates the light-sensitive cells in the retina and your brain interprets the result. When you move the dot picture farther away from your eye, the image the picture makes on your retina becomes smaller. The images of the dots overlap on the light-sensitive cells. Unable to distinguish between adjacent dots, your eye perceives shades of gray, rather than black dots and white spaces.