Lines are key to the way the brain recognises scenes

Research from the Univeristies of Stanford and Illinois have found that human brains are very adept at identifying shapes from faint and interrupted outlines.   Monitoring the activity of the brain using magneto resonance imaging, the research have inferred that the brain uses the same information to decode a scene whether they are line drawings or photos:  the bulk of the information used by the brain comes from lines and edges, rather than colours and textures.    These findings cast doubt on some models of human visual perception which argue that people need specific information that is found in photographs -- such as color, shading and texture -- to classify a scene.

http://esciencenews.com/articles/2011/05/16/whats.a.simple.line.drawing.quite.a.lot.our.brains.say