Understanding the determinants of complex behavior requires an understanding that complex behavior is multiply determined. That is, not only do the consequences of a referent behavior (RB) enter into its determination, but also the consequences of a range of available alternatives. It is not simply a matter of identifying the so-called function of behavior in a linear Occasion • Behavior ––> Consequence contingency. That analysis (sometimes referred to as an ABC analysis where the A stands for antecedent, the B for behavior, and the C for consequence) is insufficient for determining what actually controls the rate and form of an RB. This presentation will demonstrate some of the effects of such multiple, or nonlinear, determination of behavior. Several interventions based on a nonlinear contingency analysis, that would otherwise be overlooked, will be described and contrasted with that which would be occasioned by a strictly linear functional analysis.