Communication on the Brain: Lessons From the Visual System

The human brain is a massive communication device, transmitting information from the senses to the brain, and to various locations within the brain, and from the brain to the muscles. I use examples from vision to illustrate that communication in the brain cannot be distinguished from uses to which the information is put, or from the analysis of the input. Attention acts as a powerful filter that selects aspects of the visual scene, so that we don't notice much of what is in front of us. Once selected, visual objects are systematically dismantled, with information about the identities of objects sent to one part of the brain, and information about circumstantial features, such as colour, movement, location, and orientation, sent to others. This means that the information is transmitted partly in parallel, which makes for rapid processing. The question then arises as to how the scene is put back together again. I argue that this is a false issue. Contrary to what we think we see, visual perception is an interrogation device, in which we only use the information we need.