This process may be represented by where is the phrase received by the hearer. If I desire to transmit a word to you, it is assigned to x and the function encodes the word, producing the input to the function. When one desires to add additional functionality to this hierarchical model, it becomes necessary to add both encoding and decoding functions for an added layer, e.g. and . One of the advantages of this form of model is that it allows for personal processes to operate differently from one individual to another, as long as they are largely reversible within the individual. This allows one to incorporate personal factors, cultural biases, etc. into higher level cognitive processes near the top of the hierarchies.
Information is always and only transmitted through a series of physical processes.
In some cases, it may be helpful although not necessary to view this set of processes in a hierarchical manner because of the inherent hierarchical nature of communication and representation systems. In representational systems, one representation may represent another representation, such as when these printed words represent English language terms representing some ideas in the author's brain. The movement of a neural signal from a sensory organ to various parts of the brain is evidence of both a simple connection of processes and a hierarchical view of communication. For example, a given human mind may communicate through a number of different physical processes, such as through speech, gesture, or the written word. The same knowledge process can be working in the brain, but the transmitted message is traveling to its destination through one or more of several different physical methods.