Perceptual Constancy

There is a tendency to maintain constancy (of size, color, and shape) in the perception of stimuli even though the stimuli have changed. For example, you recognize that small brownish dog in the distance as your neighbor's large golden retriever, so you aren't surprised by the great increase in size (size constancy) or the appearance of the yellow color (color constancy) when he comes bounding up. And in spite of the changes in the appearance of the dog moving toward you from a distance, you still perceive the shape as that of a dog (shape constancy) no matter the angle from which it is viewed.