All too often when we think of perspective (the rendering of the illusion of three-dimensionality on a two-dimensional surface), we tend to think only in terms of LINEAR perspective--lines, vanishing points, horizons, etc.
However perspective down through the ages has also been accomplished by artists using others means--aerial perspective, size perspective, color perspective, overlapping perspective, placement perspective, etc.
Aerial perspective--the dulling down of color and edges to create the illusion of depth.
Size perspective--large objects in a picture tend to "read" closer than smaller ones.
Color perspective--dull colors recede, bright color come forward.
Overlapping perspective--objects overlapped recede, giving way to the overlappers.
Placement perspective--objects placed near the bottom of a canvas tend to come forward while those higher up tend to recede (all other things being equal of course).