Perception of textures and space- learned behavior.

The following comes from "Visual Intelligence" by Donald Hoffmann, who is writing about our perception of objects and how we learn from experiences to make automatic inferences, which help us to understand the world that we live in. For example, looking at the fabric hanging in my cubicle, I can say that I know what the material will feel like, not only because I have touched them before, but because I can identify with how the texture of the fabric looks and can predict what it will feel like from experience. The following was a case study published in 1728 by William Cheselden about a boy between 13 and 14 who had eye surgery which enabled him to see after being blind his whole life from congenital cataracts. The boy had problems identifying the differences between a cat and a dog until he was able to catch the cat and know it was a cat by feeling it. In the study they also showed him pictures , which only after a couple of months he realized they were supposed to represent solid structures. Before the realization he had considered them only flat planes comprised of colors and was surprised, after realizing their representation, that although they looked 'round and uneven' they felt only flat.

We do this kind of depth inferring all the time. A good example is the Necker cube of which I have included a picture of above. To the touch it is a flat plane, but we perceive the cube as having depth or 3 dimensionality. Also, we perceive it in two different ways, one in which the box is receding in, and one in which the box is popping out upwards. You construct the cubes that you see although they do not really exists. You mind is constantly trying to construct and perceive images in context to the database of information it has access to.

In reality, and by reality I mean the world around us, we are constructing all the depth we see. Depth is a function of our mind putting together the two images received from your eyes, and in turn, people even see at different depth. So if people do see at different depths, which is the right one? Is there a 'true depth'?