Constancy

Constancy is the human tendency to perceive objects as unchanging, despite changes in sensory inputs.

Although perspective, lighting, color and size constantly change as we move, we perceive object to remain constant and unchanging.
It makes sense of what we see around us.

The road looks small as it goes on but it really doesn't change

Different forms of constancy are referred to as :

Size Constancy :

Size constancy is when people's perception of a particular object size does not change regardless of the change in distance of the object.

Objects appear to stay the same size even though the size of the images change as they get nearer or further away.

This is because the perception has made adjustments to the information.

Shape Constancy :

Shape constancy is when people's perception of the shape of an object does not change regardless of changes to the object orientation.

We keep a constant shape in our mind for each object no matter what the angle we look at the object.

Color Constancy :

Color constancy is a feature of human color perception system that ensures that the color of an object is perceived as similar even under varying conditions.

It is the ability to perceive colors of objects, invariant to the color of the light source.