On defining resurgence.

A review of different investigators' definitions of resurgence revealed several common features: First, characteristics of the resurgent, or target, response, such as its transience; magnitude; time course within and across sessions; and relativity to a baseline response rate are not mentioned. Second, the target response is described as being established through its reinforcement in the first, or Training, phase of a resurgence procedure. Third, the target response must be eliminated as an alternative response is reinforced in the second, Alternative Reinforcement, phase of a resurgence procedure. Fourth, the alternative response must be extinguished during the Resurgence Test phase. Fifth, none of the definitions allude to any contribution of stimulus variables to resurgence. When reconsidered in light of contemporary research germane to these features, none of the reviewed definitions sufficiently reflect important variables in the generation and assessment of resurgence. The review concludes with a proposed working definition that takes into account contemporary research involving all of the aforementioned factors.