The term NCR had been used for many years in the Journal of Applied Behavior Analysis (JABA) and other journals prior to the publication of our study. Similar (equally problematic) terms, such as response-independent reinforcement, were used in the Journal of the Experimental Analysis of Behavior (e.g., Zeiler, 1968). Historically, the term was used to refer to a control procedure designed to test reinforcement effects; that is, to demonstrate the effects of a contingency (e.g., Goetz, Holmberg, & LeBlanc, 1975). In our study, we were simply using a term that had been used previously. It is important to note that, in the same article, we also used the term differential reinforcement of other behavior (DRO) to describe another procedure. It occurred to us that the terms DRO and NCR both had potential limitations. I defer to Poling and Normand's commentary to describe the limitations of the term NCR, but I will briefly mention one example of the difficulty we were faced with in using the term DRO.
The procedure known as DRO involves stimuli or events made contingent on the omission of behavior. If DRO is effective, the target behavior is weakened and therefore the use of the term reinforcement (the R in DRO) is problematic. It can be (and has been) argued that interresponse times (IRTs) are modifiable units and, hence, progressively longer IRTs are in fact reinforced (strengthened) in a DRO. Also, it is possible that all "other" behaviors that occur prior to stimulus delivery are being strengthened via reinforcement and, hence, compete with the target behavior (which is now on extinction). However, during any given behavioral treatment, it is not clear that DRO effects result from strengthened IRTs or reinforcement effects. Extinction and satiation are equally viable mechanisms underlying DRO effects. It is interesting to note that time- based schedules could also have their effects by "reinforcing" other behavior or longer IRTs (albeit incidentally), or by satiation and extinction (Iwata, 1999). The problem with using the terms DRO and NCR is that neither necessarily meets technical criteria for using the term reinforcement. By no means am I suggesting that we now abandon use of the term DRO; its roots are too deep and its use seems reasonable given the possibility of reinforcement effects. Rather, I raise the point because it exemplifies parallel terminology limitations with NCR, and also points to mechanisms by which time-based schedules may actually involve reinforcement under some circumstances. When we initially published our 1993 paper, we could have abandoned both or abandoned neither term. We felt that moving against convention would detract from the central focus of our study and that we did not have enough data to do so convincingly.
Almost certainly, some JABA authors will argue that the term NCR should continue to be used. One reasonable argument is that using NCR has served a good purpose. The term seems to have led, in part, to the recognition of a general class of procedures to be used as treatment. This may not have happened so quickly and comprehensively if we referred to the procedure initially as fixed-time attention. Calling the procedure NCR gave it status as a treatment package on par with DRO, insofar as both names describe a general procedure that is not limited to any particular stimulus or event (e.g., the event can be food, attention, escape, toys, etc., in either NCR or DRO). The descriptor fixed time requires reference to a specific type of stimulus (attention) and does not imply that the stimulus had already been shown, via functional analysis, to reinforce the problem behavior.
To conclude, I have always agreed with assertions that the term NCR is technically inaccurate. A combination of historical and procedural considerations led to its use. However, because it is reasonable to conclude that using the term NCR has served a useful purpose, some authors may be inclined to continue its use because of convention. Although I now use schedule descriptors in my own work (e.g., Vollmer et al., 1998), I am not entirely content using them. Fixed-time (event), for example, does not capture the generality of the procedures, nor does it capture an essential property of the treatment: The noncontingent event bears a known functional relationship to the target behavior. Whatever we call it, the procedure has proven useful. I thank Poling and Normand for setting the record straight on terminology.
Iwata, B. A. (1999, January). Noncontingent reinforcement: Terminology, control functions, and therapeutic applications. Paper presented at the 17th annual conference of the California Association for Behavior Analysis.
Poling, A., & Normand, M. (1999). Noncontingent reinforcement: An inappropriate description of time-based schedules that reduce behavior. Journal of Applied Behavior Analysis, 32, 237—238.
Vollmer, T. R., Iwata, B. A., Zarcone, J. R., Smith, R. G., & Mazaleski, J. L. (1993). The role of attention in the treatment of attention-maintained self-injurious behavior: Noncontingent reinforcement and differential reinforcement of other behavior. Journal of Applied Behavior Analysis, 26, 9—21.
Vollmer, T. R., Progar, P. R., Lalli, J. S., Van Camp, C. M., Sierp, B. J., Wright, C. S., Nastasi, J., & Eisenschink, K. J. (1998). Fixed-time schedules attenuate extinction-induced phenomena in the treatment of severe aberrant behavior. Journal of Applied Behavior Analysis, 31, 529—542.
Zeiler, M. D.(1968).Fixed and variable schedules of response-independent reinforcement. Journal of the Experimental Analysis of Behavior, 11, 405—414.
Received February 2, 1999
Final acceptance February 15, 1999
Action Editor, F. Charles Mace
Address correspondence to Timothy R. Vollmer, Psychology Department, University of Florida, Gainesville, Florida 32611 (E-mail: Vollmer@psych.ufl.edu).