Stimulus, Response, and Intellect

According to one standard model, behavior has a 'stimulus-response' ('SR') structure, namely, that, at bottom, all behavior is a response to some stimulus. At its most basic, response follows directly upon stimulus, as if they composed one continuous circuit. In SR theories in general, Intellect is regarded as intervening in the circuit, introducing calculation into it, pertaining to the possibility of a variety of responses to a stimulus. The capacity of Intellect is thus the grounds of the distinction between 'lower' and 'higher' creatures, with many gradations in between. But the distinction is not necessarily inter-species; rather, it can be discerned within a matter of inches on one and the same human organism. A blow to a certain spot just below the knee will immediately be followed by a small kick of the leg, while one to a spot just a few inches below that might also be followed by a kick, but it also might be followed by linguistic comment, a punch, or a flight away. In the latter case, some calculation has preceded the ultimate response. One important criticism of the scope of SR is that it oversimplifies the lower-higher distinction, especially insofar as it ignores a crucial factor in the response phase, namely Habit. The criticism acknowledges that a habitual response is as automatic as a reflex, but it maintains that habits can be changed. To which a defender of SR can argue that the changing of a habit simply entails a redirecting of response, via reward or punishment. However, as especially Stoicism has shown, given a stimulus, one option is not merely either a habitual or a novel response, but no response at all. The Stoic can thus argue that what the SR model most notably glosses over is that the Intellect is not merely calculative, but constraining, as well.