This study detailed a method of data analysis called lag-sequential analysis to examine the relations between severe problem behavior emitted by adolescents and the behavior of their caregivers. The stimulus functions of common antecedents and consequences (e.g., attention, escape from demands, and delivery of toys) were evaluated for each participant using functional analysis methods similar to those described by Iwata et al. (1982/1994)
. Lag-sequential analyses were then performed on data collected during interactions between caregivers and adolescents with severe problem behavior. Potential reinforcement contingencies were found to follow one or more of three basic patterns: (a) Conditional probabilities (of putative reinforcing events) were higher following problem behavior than before problem behavior, (b) conditional probabilities were higher following problem behavior than were conditional probabilities given no problem behavior (and unconditional probability), and (c) problem behavior was correlated with a change in the trend of conditional probabilities (e.g., although the conditional probability of no demands for Alice was not initially high following problem behavior, problem behavior was correlated with a change in trend from decreasing to increasing probability). To our knowledge, this is the first demonstration of momentary fluctuations in probability of events after identifying reinforcers via functional analysis. Thus, the present method represents a tentative step forward to examine potential reinforcement contingencies that operate in the natural environment.
It is important to emphasize that the current application of descriptive analysis was not intended to replace the role of a functional analysis. This study did not involve a comparison between functional analysis and descriptive analysis methods. Instead, the approach was designed, in a sense, to take a snapshot of behavior and environmental events and then to evaluate the snapshot after reinforcers had been identified via functional analysis. The idea is that it may be useful to understand how, and in what relation to behavior, events similar to those identified in the functional analysis actually occur during adult–child interactions. Thus, the approach was not presented as a clinical assessment procedure and should not be construed as such. Specifically, we do not recommend that a lag-sequential descriptive analysis be inserted into a functional assessment regimen. Rather, it is hoped that the information obtained from the study might be useful to application and in future applied research.
One way the study might influence future application is by emphasizing the complexity of reinforcement contingencies. Although it is perhaps not surprising for behavior analysts, the results suggest that potentially reinforcing events might exert influence over behavior even when they occur in very subtle ways. For example, in Alice's case, the negative contingency present in the first 11 s following problem behavior suggests that her caregivers were implementing something akin to brief differential reinforcement of other behavior. However, the data also show a positive contingency between Seconds 12 and 45. From Alice's perspective, it may be that although problem behavior did not immediately produce a break from demands, her caregivers were more likely to provide escape after a brief delay. Such a pattern could be missed by a casual observation or even the calculation of conditional probabilities 10 s following problem behavior. To address this, specific training could be provided to Alice's caregivers to continue implementing demands for 1 min following problem behavior.
A second way that the study might influence future research is from its emphasis that descriptive research should continue not necessarily for the purpose of identifying methods as suitable replacements for a functional analysis but rather for the purpose of identifying the kinds of potential reinforcement contingencies that should be evaluated in both basic and applied research. For example, although research on descriptive analysis has focused on the identification of positive contingencies between behavior and environmental events, it is possible that in some cases behavior could persist in the presence of a negative or neutral contingency. An individual with an extensive reinforcement history might continue to engage in problem behavior in the face of a treatment involving differential reinforcement of other behavior. It is possible that, under such conditions, the occasional mistake of delivering a reinforcer following problem behavior could serve to maintain behavior, despite the overriding negative contingency in place. We are currently evaluating negative contingencies and history effects in our animal operant laboratory (Samaha, Vollmer, & Osteen, 2005
), and we hope to extend that research to severe behavior disorders. For example, how negative does a new contingency need to be in order to suppress behavior previously reinforced by strong positive contingencies?
The specific approach used in this study, lag-sequential analysis, has advantages over other data-summary approaches (e.g., it allows moment-to-moment evaluations of probability), but it also has clear disadvantages. In some cases, the lag-sequential analysis provided a plausible description of behavior and reinforcement in the natural environment. Alice's attention data (, top) are perhaps the clearest, reflecting a clear change in the conditional probability of attention before and after problem behavior and following problem behavior compared to following seconds without problem behavior. In other cases, different contingency measures provided contradictory information. Amy's access to materials data (, top) reflect hardly any discernible change in the probability of access before and after problem behavior, but a clear difference in the comparison between conditional probabilities given problem behavior and seconds without problem behavior. In other cases, results of the lag-sequential analysis failed to describe any plausible reinforcing relation. Greg's access to materials data () show the largest obtained difference between the probability of a potential reinforcer following problem behavior compared to following seconds without problem behavior, yet in a direction opposite than that expected for the reinforcement of problem behavior. In fact, an examination of the session-by-session data suggested no clear relation between the potential reinforcer and problem behavior. A within-session analysis showed that he had undisrupted access to materials prior to and during problem behavior during the session in which he engaged in the highest rates of problem behavior. One possible explanation for the failure to identify a plausible reinforcing relation is that the reinforcer for Greg's problem behavior was not presented (contingent on behavior) during the descriptive analysis. If so, problem behavior may have been reinforced in some other environment and occurred during the descriptive analysis as a result of generalization or induction. This problem raises a larger question: How much descriptive data are needed to provide a representative sample of events?
In addition to concerns about the lag-sequential approach itself, there are other limitations to the current study that are perhaps inherent to descriptive research. Supposedly similar events were delivered as consequences during the functional and descriptive analyses. For example, the attention delivered by the therapists during functional analysis sessions may have been functionally different than the attention delivered by caregivers during the descriptive analysis. Similarly, it is not known whether periods without demands function similarly to periods of transition from demand to no demand (i.e., a true escape contingency). Attempts were made to incorporate similar forms of attention, preferred materials, and demands into the functional analysis that were observed in the descriptive analysis; however, no claim is made that the events were exactly the same. Future research might attempt to increase the similarities between functional and descriptive analyses by having caregivers serve as therapists during the functional analysis sessions or by attempting to assess the relative reinforcing efficacy of events as delivered by caregivers and therapists.
In conclusion, a method for identifying possible reinforcement contingencies was evaluated. It was necessary to conduct a functional analysis to identify the stimulus functions of possible reinforcers. In future work, functional analyses could be conducted using contingency arrangements similar to those found in the descriptive analysis. Perhaps these analyses will allow more to be learned about the nature of reinforcement.