focus on identification and treatment of toddlers with autistic spectrum disorders, in contrast to previous models of early intervention that began when children were in preschool or elementary school.
The ten program models described derive from either developmental or behavioral orientations, which influence goals, intervention procedures, and methods of evaluation. Thus, the Denver Model and the Developmental Intervention Model were conceptualized from a deductive framework, in which developmental theory was used to organize hypotheses regarding the fundamental nature of autistic spectrum disorders. Group design research has been aimed at seeking confirmatory evidence regarding deviations from normal development that need to be addressed in intervention. With the exception of TEACCH, which is eclectic with elements of both developmental and behavioral orientations, the other seven programs derive from the field of applied behavioral analysis. Behavioral interventions have been developed from a “bottom-up” approach in which procedures based on principles of learning are subjected to (largely single-subject) empirical tests, and techniques of demonstrated efficacy have then been assembled into program models (Anderson and Romanczyk, 1999).
Although these differing conceptual frameworks influence the intervention models in substantial ways, in practice, there is also considerable overlap between and across the various models. Within the behavioral approaches, a wide range of applications are used within and across programs, ranging from traditional discrete-trial training procedures to newer naturalistic approaches.
The Denver Model recognizes the interplay among cognitive, communicative, and social and emotional development (Rogers and DiLalla, 1991). It was originally based on Piaget’s (1966) experientially based theory of cognitive development, with additional influence from Mahler’s conceptualization of interpersonal development via the attachment-separation-individuation process (Mahler et al., 1975). The underlying assumption was that, if intervention is directed at establishing strong, affectionate interpersonal relationships, then it may be possible to accomplish broad developmentally crucial improvements. From this perspective, it has been argued that the traditional behavioral approach of teaching specific behaviors is too narrow to have an impact on the fundamental nature of autistic spectrum disorders (Rogers et al., 1986). Although the Pivotal Response Model evolved from behavioral research, it arrived at a similar