If the goal is to distinguish behavior subject to choice from behavior precluded from choice, reclassifying ε_s as an environmental constraint may yield clarity.

In light of this formulation of the lens model, return to Simon’s remarks concerning the classification of environmental affordance versus behavioral constraint. The conception of the lens model as a linear model is indebted to signal detection theory, which was developed to improve the accuracy of early radar systems. Thus, the model inherits from engineering a clean division between subject and environment. However, suppose for a moment that both the environmental mechanism producing the crite