Or is it lack of cognition? 

By Richard Russell Posted Friday 2nd February 2007 10:37 GMT

I have noticed that the degree of attention I have for detail grows with my knowledge of the subject. When visiting unfamiliar places, for example, I fail to notice many details which on later visits, when I have become more educated on the place, are hard to miss. (How I wish I could think of an example at this point!)

"Seeing" is a complex process. The light rays pass onto our retina, the optic nerve responds, somewhere the brain registers a stimulus. But true "noticing" involves a cognitive response. If we don't have an understanding of the light-patterns falling on our retina it gets discarded.

Put another way, we don't just see shape X, we see "a house", "an animal", a "something-we-understand". And if we don't understand the chances are we just don't take any notice.