Representational systems (also abbreviated to VAKOG) is a postulated model from neuro-linguistic programming, a collection of models and methods regarding how the human mind processes and stores information. The central idea of this model is that experience is represented in the mind in sensorial terms, i.e. in terms of the putative five senses, qualia. According to Bandler and Grinder our chosen words, phrases and sentences are indicative of our referencing of each of the representational systems. So for example the words "black", "clear", "spiral" and "image" reference the visual representation system; similarly the words "tinkling", "silent", "squeal" and "blast" reference the auditory representation system. Bandler and Grinder also propose that ostensibly metaphorical or figurative language indicates a reference to a representational system such that it is actually literal. For example, the comment "I see what you're saying" is taken to indicate a visual representation. Further, Bandler and Grinder claim that each person has a "most highly valued" (now commonly termed preferred) representational system in which they are more able to vividly create an experience (in their mind) in terms of that representational system, tend to use that representational system more often than the others, and have more distinctions available in that representation system than the others. So for example a person that most highly values their visual representation system is able to easily and vividly visualise things, and has a tendency to do this more often than recreating sounds, feelings, etc. Representational systems are one of the foundational ideas of NLP and form the basis of many NLP techniques and methods. Representational systems within NLP For many practical purposes, according to NLP, mental processing of events and memories can be treated as if performed by the five senses. For example, Albert Einstein credited his discovery of special relativity to a mental visualization strategy of "sitting on the end of a ray of light", and many people as part of decision-making talk to themselves in their heads. The manner in which this is done, and the effectiveness of the mental strategy employed, is stated by NLP to play a critical part in the way mental processing takes place. This observation led to the concept of a preferred representational system, the classification of people into fixed visual, auditory or kinesthetic stereotypes. This idea was later discredited and dropped within NLP by the early 1980s, in favor of the understanding that most people