In the late 1970's, John Grinder (a professor at UC Santa Cruz) and Richard Bandler (a computer sciences professor interested in psychology) got together and became interested in how psychotherapy worked. Specifically, they asked the question, "If these fantastically gifted therapists (Milton Erickson, Virginia Satir, Salvador Minuchin, and others) all get great results, how come they all claim they are doing different things and describe what they do and how they do it so differently?"
Bandler and Grinder developed a way of looking at how therapy works to help people change, by observing these therapists as they worked with people. They developed a model of how psychotherapy works. A model is not the same as a theory, which is based on constructed ideas - a model looks at what happens, but not why it happens.
The first part, the linguistic portion of the model, describes how therapists use language to challenge the belief systems of their patients, and also how hypnosis works (linguistically, the opposite of how therapy works). A linguist named Noam Chomsky developed a theory of language which states that the Surface Structure of a phrase or sentence contains elements which point to the Deep Structure, a set of beliefs and assumptions about the world. Bandler and Grinder found that certain types of words represent not-useful beliefs that lead to depression and other limitations on behavior. By helping patients to more accurately specify the details of their world, their view of it and of themselves becomes filled with more possibilities.
For example, when people use "modal operators of possibility" such as always, never, etc., they are telling themselves that a specific problem exists constantly and thus that nothing can be done about it. Almost nothing happens constantly. "He always tells me what to do!" "Always?" "Well, . . ." By challenging this aspect of the patient's belief system, their view of their world is expanded and enriched, and their perceptions of its limitations are reduced.
The second part, the "neurological" portion, was especially interesting because of its emphasis on the use of unconscious "accessing cues" such as eye movements to show how information is being processed internally. NLP postulates three main "sensory representational systems" (visual, auditory and kinesthetic) within and between which information is maintained and transformed. These representational systems are used in sequences, and the sequence of representational systems used is what determines the outcome of the information processing. For each person, there is a correlation between the direction of eye movement accessing cues and the representational system being used (that is why we often look away momentarily when we are accessing information).
By observing which sequences of representational system use result in which emotional and behavioral outcomes, negative outcomes can be altered to more closely resemble more desirable outcomes. Bandler and Grinder developed a set of techniques which elicit information in one representational system and associate it with information in another, which they called "anchoring." There are a variety of techniques which use these principles, such as one to help people remember traumatic experiences without feeling the emotional trauma again, called the Visual-Kinesthetic Dissociation, and one using imagery to replace an unwanted outcome with a more desirable one called the "Visual Swish."
The end result of the use of these techniques is that certain problems which used to require many structured behavior therapy sessions to resolve, can now be resolved in a few sessions. Phobias, habits, poor interpersonal skills can all be addressed using techniques of NLP.