Rules: Function-altering contingency-specifying stimuli.

Behavior analysts have traditionally defined rules as discriminative stimuli. Three problems with this interpretation are discussed. First, because the effects of rules are often delayed, and the effects of discriminative stimuli are immediate, classifying rules as discriminative stimuli violates the definitional requirements of the latter. Second, when rules are defined as discriminative stimuli, other truly unique effects of rules may be obscured. Finally, both rules and contingencies develop new behavioral relations; however, when rules are interpreted as discriminative stimuli, their effects are not readily compared with those of contingencies. As an alternative, we suggest that rules be interpreted as function-altering contingency-specifying stimuli. Implications of this function-altering interpretation for terminology and research strategy are discussed.