In some situations, our 
motion or that of objects does 
seem to lead reliably to the 
perception of depth. In contrast 
to viewing luminous circles 
that appear suspended in space, 
suppose, for example, that we 
see the elements in a plane 
change direction as we move. If 
we are watching the landscape 
pass by from a rapidly moving 
car, for instance, we see the 
elements of the texture of the 
ground, be they stalks of wheat 
or pebbles on a beach, change 
their direction as a function of 
their distance. Our motion 
creates a gradient of change in 
the direction of objects, with 
nearby elements changing 
rapidly and distant ones 
changing hardly at all. Gibson 
called the information we 
gather from such moving 
perception of elements in a 
plane motion perspective, 
because it is analogous to 
perspective information in 
stationary scenes, and he 
argued that it is a central factor 
in our perception of depth.