Generalization, Deletion, Distortion
Generalization, deletion, and distortion are what Bandler and Grinder describe as "the three universals of human modeling." Building on the idea that our experience of the world is, in fact, the experience of our model of the world, they propose these universals of human modeling as responsible for the difference between the world and our models of the world. In addition, Bandler and Grinder (in The Structure of Magic, vol.1) illustrate how these three distinctions are reflected in the patterns of everyday language. Due to generalization, deletion and distortion our language is an impoverished representation of our model of the world (our model of the world is itself an impoverished representation due to these same three processes).
So far, so coherent. But it doesn't get any better than that. In fact, it gets a lot worse. (It is a characteristic of the domain of description that our coding always has cracks in it. It is into those cracks that the postmodernists sought to insinuate their cognitive crowbars and to move the Universe. But they'd forgotten that the Archimedes riff included not only "a lever long enough" but also "a place to stand." Perhaps fortunately, the postmodernists' project allowed of no place to stand, so all they could move were the universities.) The terms Generalization, Deletion and Distortion make a pretty good filter when it comes to capturing the nature of the reducing valve through which our experience dribbles in from the cosmic vastness. They have that, "Uh, huh, yeah" quality. But when it comes to a close reading of Structure I, and an attempt to pull together the various ways in which Bandler and Grinder define and describe these processes, it looks like those very same processes have been playing fast and loose with their description. Retreating then, from the bootless struggle to nail this one to the page, we are free to speak of these distinctions in our own way.
We will take "generalization" to be the process through which our beliefs are formed. We generalize from a number of experiences (and that number can be 1, if it is compelling and/or intense enough) and form our conclusion about what is equivalent to what or what causes what. We come to such conclusions about anything, anything from what hues we are ready accept as "red" to how we know we are going to be saved by aliens when the apocalypse comes. In between, we might live out of generalizations such as "love hurts," "the Everly Brothers' songs carry significant life wisdom," "having a pink Cadillac isn't manly," "we should do unto others as we would have them to do unto us," and "success and fame equals a long sleek black limousine full of slinky women in a snowstorm." We live in, and act out of, a web of generalizations.
As Steve Andreas points out, the word "deletion" implies that we are chopping out great chunks of reality and throwing them over the side. It is more useful to recognize that our attention is, necessarily, selective and that whatever we are paying attention to will leave a whole lot of other stuff unattended to, and thereby missing, or deleted, from our awareness at that point.
It is trickier to define "distortion" in that distortion is a mote in the eye of the beholder. While the process of deletion concerns selection, the process of distortion concerns accuracy. And one person's accuracy is another person's distortion. Different people distort in different ways. Different cultures do it, too. Everybody's doing it. Then there are those who do it in a way that falls outside the social consensus, into criminality and craziness.
Obviously, there are close connections between these three processes. The selectivity that is involved in deletion will impinge on the matter of accuracy and might, on those grounds, be accounted a distortion. However, in our thinking, generalization is of a different type. Both selectivity of information and its distortion are involved in the creation of generalizations. However, it is existing generalizations, more than the processes of deletion and distortion, which will have the greatest influence on what new generalizations are formed.
Typically, the three processes are spoken of as if they fall between the world and the sense we make of it. This is their role as molders of meaning. It is usually presented as if it were the traffic cops guarding a one-way street. Of greater significance might be their feed-forward role. These same processes largely determine ahead of time what will be selected by our attention to begin with and in which ways that which is selected will be distorted.
In line with our emphasis on the importance of beliefs, it will be no surprise to find that we hold that generalizations (our beliefs) are the determinant of both selection and distortion. At this point we would have liked to give examples of beliefs where readers would concur that the processes of deletion and distortion were in full play. Unfortunately, for every example we could come up with we could imagine a reader arguing with us, "But that is true. That's how things really are." Which just proves the ubiquity of these processes and how central they are to the way we live. Our tendency is to maintain our beliefs. Challenges to them are usually not welcome. Our beliefs are the ground upon which we stand and from which we act, and it is troublesome to have them unsettled. It can feel like trying to do a pole-vault when you're standing in quicksand.
Through selective attention and distortion we tend to perceive only those things which fit our beliefs. We resist challenges because challenges can become counter-examples, and counter-examples undermine the solidity of a belief, or actually breach it. And allowing that to happen runs counter to our desire to maintain personal coherence.