Behavioral Challenges To a growing extent, strategies for promoting engagement have become nearly synonymous with methods of preventing challenging behaviors (McGee and Daly, 1999), because the behavioral challenges presented by young children with autistic spectrum disorders are usually not of a severity to warrant more intrusive intervention procedures (see Chapter 10). However, the Young Autism Project acknowledged use of aversive procedures with children participating in a 1987 outcome study. In a recent replication, aversives were discontinued after the first few subjects (Smith, 2000b). In another replication of the Lovaas (1987) outcome study, there was speculation on the possibility that the absence of aversives could have accounted for less positive child outcomes (Anderson et al., 1987).

At least five approaches (i.e., Denver, Individualized Support Program, LEAP, Pivotal Response Model, and Walden) rely exclusively on positive procedures for preventing challenging behaviors or for building incompatible appropriate behaviors. Because the Individualized Support Program model is a more short-term, problem resolution approach (Dunlap and Fox, 1999a), a comprehensive positive behavior support strategy has been developed to accomplish demonstrable improvements in relatively short time-frames (see Chapter 10).

Motor Skills The Developmental Intervention Model places a major emphasis on motor skills, including motor planning and sequencing. Most of the programs teach age-appropriate gross and fine motor skills. The UCLA program encourages gestural and vocal imitation. The Denver Model emphasizes motor imitation and motor planning.

The ten representative programs use a range of research-based teaching procedures. The behavioral programs use procedures based on principles of learning, but the format of instruction falls along a continuum of discrete-trial procedures to incidental teaching. At the ends of the continuum, the Young Autism Project has historically used discrete-trial procedures nearly exclusively (Lovaas et al., 1981), while Walden provides all instruction using an incidental teaching approach (McGee et al., 2000). The other five behavioral programs use a mixture of discrete-trial and naturalistic teaching procedures, although the Individualized Support Program (Dunlap and Fox, 1999a), LEAP (Strain and Cordisco, 1994), and the Pivotal Response Model (Koegel et al., 1999a) models use predominately natural context procedures, and the Children’s Unit most commonly uses a highly structured discrete-trial approach (Romanczyk et al.,