Perceptual Constancies- Shape Constancy

Shape constancy can be defined as the tendency to perceive the shape of an object to be constant, despite differences in viewing angles.

For example when you walk to the dinner table, the shapes of the plates do not change (visually). That is because the shapes of the plates are elliptical on your retina, so they appear the same.

The end result of this example below can be explained because even though you rotated the object, it will still appear the same as it did when you looked at it straight on. But the actual image of the plate, on your retina, has changed a lot.