Validation of the verbal behavior package: Old wine new bottle- A reply to Carr & Firth (2005).

Abstract

Abstract A recent commentary by Carr and Firth (2005) called for case studies and controlled longitudinal research to validate the verbal behavior (VB) approach to early intensive behavioral intervention for children with autism and related developmental disabilities. They contrasted the verbal behavior (VB) approach (Sundberg & Partington, 1998) with the Lovaas approach (Lovaas, 1987) by highlighting two unique features of the VB approach, including (1) its reliance on Skinner's (1957) functional analysis of language and (2) its use of natural environment training (NET) to target language. The current paper notes that neither of these features (functional language training or NET) is new to specialists in language intervention. More than 35 years of research from the fields of speech-language pathology and behavior analysis supports these practices. While validation is clearly needed to support the VB package as a whole, practitioners do have a rich history of literature to support the individual strategies within the package. Keywords: behavior analysis, verbal behavior, early intervention, language disabled populations, and autism Introduction Gilbert (1996) described a fundamental tension between scientists and engineers. He characterized scientists as humble individuals who focus on how little is known while portraying engineers as bolder spirits who argue that much is known while little is applied. This contrast comes to mind when reading Carr and Firth's (2005) interesting commentary on the need for research to validate the verbal behavior (1) (VB) approach to early intensive behavioral intervention (EIBI) for children with autism spectrum disorders (ASD) and other developmental disabilities (DD) (Sundberg & Partington, 1987). The need for treatment efficacy research cannot be denied in the interest of science and in a climate of evidence-based practice; however, it also bears mentioning that the VB model rests on a considerable history of practice and research. The purpose of this paper is to support and complement the observations of Carr and Firth (2005) by summarizing the theoretical and empirical literature pertaining to selected components of the VB model with emphasis on those pertaining to natural environmental training (NET). Carr and Firth (2005) noted, appropriately, that support for the VB approach currently exists primarily in the form of studies on the training of single verbal operants to individuals with and without language disorders; and they noted the dearth of controlled, longitudinal outcome studies to assess the effectiveness of the VB program as a package. In considering the design of studies to address this need, perhaps of greatest interest would be an empirical study to determine whether the VB approach, if provided early in life, could significantly alter the course of a child's development as s/he approached elementary school (similar to the study conducted by Warren, & Kaiser, 1986b). For a global intervention program to make this claim, the empirical evidence would need to meet the American Psychological Association's criteria for a well-established treatment. Specifically, the evidence would need to include either (1) two randomized, controlled, group designs or (2) nine well-controlled single subject designs (Chamberless & Hollon, 1998). The type of evidence currently available to support global ABA programs (e.g., discrete trial, VB) was recently reviewed by Brandsma and Hertbert (2001). These authors found that none of the current research meets the APA standard for demonstrating that exposure to the treatment could change the developmental course of the participants. Since empirical support for global EIBI programs does not yet meet the APA standard of empirical support, it is appropriate and ethical to look at evidence supporting the sub-components of global treatment packages. Therefore, this paper will examine the level of evidence supporting components of the VB package with particular emphasis on the milieu language-training component. …