In my last blog I introduced you to the lens model. In today's blog I want to expand upon the lens model by introducing you to another important diagram that the founder of the lens model, Egon Brunswick, also used to explain the lens model.

The reason I find it necessary to expand the lens model is that I was trying to apply the lens model to the problem of preparing grape vine cuttings to achieve the maximum number of propagated vines. This happens to be a task I'm occupied with at the moment.

The problem I ran into was that the pruning policies I followed in preparing the cuttings are not best described as "cues" emitted from the environment, they are rather the "means" I have chosen to achieve a goal. The lens model seems to be more focused on accounting for "perception" than "action".

Further examination of the lens model, however, reveals that the lens model as I presented it yesterday is only the left hand side of a larger model that Egon Brunswick offered to explain the relationship between the organism and the environment. Here is the expanded lens model:

Source: Brunswik’s original lens model (PDF link).

Note the perfect bi-lateral symmetry of the model. Note also that "cues" stand between the organism and the environment on the perception end (input side) and that "means" stand between the organism and the environment on the "action" end (output side). This would seem to imply that everything I said yesterday about "cues" mediating between the world (or distal object) and the observer also applies to the "means" that mediate between some goal object and the observer.

In other words, to achieve some goal object we must select the means to get there. The lens model applies to situations where the means to achieving some goal in the future is not certain so we choose "means" that we think will get us there but which, in reality, might not have a strong relationship to achieving the goal. We have an internal model that we use to explain the relationship between the means selected and the goal object that may not in fact be the best means we could have chosen to achieve that goal object. It is a happy day when the means we have chosen have high ecological validities in achieving the goal state.

So I stand by my assertion that the lens model is a useful framework to use in understanding where simple rules might fit in the overall scheme of things. There can be simple rules for handling decision making related to the input side of things and there can be simple rules for selecting the means to achieve some goal object. We may appear to be in Plato's cave observing shadows on the wall and trying to figure out the objects that they represent, however, Brunswick's model offers the hope that we can get closer to the opening of the cave to behold the object in an ever clearer light. The distal or goal object does not live in a world of ideal forms, but rather is an object that we can focus on more or less clearly depending upon the cues and means we choose and how strongly correlated they are with the distal or goal object.

The lens model has something useful to offer investors who must make investment decisions based upon multiple unreliable cues, and for entrepreneurs seeking a goal state and needing to select from multiple means that are more or less correlated with the goal state. We are searching for best cues and the best means and these can often be formulated as simple rules.