Frozen garden and a note on Gestalt Theory
Cognitive processes, see here for a definition, are, according to Gregory Bateson, opaque. You can appreciate the causes and the outcomes but you are not aware, so to say, of what happens in between. As an example consider what is going on nailing. Certainly your brain had to do some calculations to find out the right trajectory for the hammer. But, unless the hammer goes straight to your finger, you are not aware of the calculus. Only when something goes wrong you will start to pay attention. The same seems to happen for each cognitive process. Vision is one of the those processes or better , vision is a composite of cognitive processes each with his own opacities.
In vision a lot has been showed by Cognitive Psychology as well as Gestalt Theory or Piaget (post)̠ school in the second half of the last century. To be exact in the 70/80 all the concepts already had been incorporated in psychology course books.
Gestalt Theory gave a frame for understanding several visual perception phenomena, like the one known as "Closure". But more important showed (in good company with the others) that each of our senses has different thinking models to interface with. Each of the schools had their own methods to demonstrate what postulated. Gestalt theory, as well as others, proceeded by showing cases of explicit specialized thinking (like completing the missing pieces out of hidden parts of a cube or paying attention to where the hammer is going :-) in form of perceptive experiments (something gone wrong or perceptually unexpected). The strength of the experiments outcome helped a lot in terms of popularity. Eventually it came out that some of the experimental models could be rendered in figures or photographies. R. Arnheim being one of the latest of the school is also one that more applied himself to Visual Perception and Thinking in the Gestalt Theory frame. If looking for a synthesis of the theory he represents a good entry point see here. I recommend his book "Visual Thinking" (the first 3 chapters are more than enough).
Photographers, and image makers in general, are attracted by Gestalt Theory in their never ending quest to the perfect rule for the successful image. But in general most of the adventurous end up questioning if it was worth reading hundreds of pages about experiments to understand that framing matters (Ansel, to cite a verbose one, treated all of that in far less, Paul Strand did it in pictures and Capa, while busy setting up the next decisive moment, said it in the shortest form).
But if taken at large, forgetting the quest for the photographic stone, what Cognitive sciences show us is that there is a visual form of thinking, with its own rules and forms and not always homomorphic to other thinkings. The concept of "Visual Thinking" has a long history if seen through the history of image making. A very interesting point is made in the "Metaphysics" artistic theory developed by the De Chirico Brothers at the beginning of the last century. The main idea was to detach any verbal or affective connection with what saw to obtain, or make visible, the pure visual relations among the viewed things.