What is the background?
Robert Dilts designed the model of logical levels in the mid 1980s. He formulated them according to Bateson's logical levels of learning. In NLP they have gained immense importance since their publication. In book form they were probably first published in 1990 in "Changing Beliefs with NLP". Robert calls them, Neuro Logical levels as they reflect levels in the way we can process or think about them
Gregory Bateson formulated the concept of Logical Levels of learning as a mechanism in the behavioural sciences, based on the studies by Bertrand Russel. Bateson identified four basic levels of learning and changing, after which Robert Dilts supplemented this up to six: identity, values and standards, possibilities, behaviour, and environment.