Technical Review of Published Research on Applied Behaviour Analysis Interventions for People with Autism Spectrum Disorder

Results 9. Generalisation of Abilities across Multiple Natural Environments

Generalization of effects to natural environments is difficult to assess. Tracking individuals to a range of environments is expensive and may produce a reactive effect (as individuals in the environment become aware of the observations taking place), thus making the generalization setting “unnatural”. Despite these limitations, a large number of studies provided an assessment of whether main effects were generalized.

Ninety one (53.8%) of the 169 items were selected for further analysis because they gained SMRS scores of 2.0. Forty-five of these (49.4%) assessed whether the main effects had generalized. These studies were of high quality with 31 of them achieving an SMRS rating of 3 or higher for design and 42 receiving a rating of 3 or higher for measurement of the dependent variable. Almost all of the studies receiving lower scores for design did so because of a small sample size rather than any design flaw.

1. Three of the 45 items (6.7%) did not find evidence of generalized main effects. Two of them addressed interpersonal skills while the third concerned problem behaviour. The interventions used traditional generalization tactics such as thinning schedules of reinforcement and programming common stimuli. Two of these studies also reported limited support for the main effects.
2. Fourteen items (31.1%) reported limited support for generalized effects and all but one of them also reported strong support for the main effect. The skills studied included communication and interpersonal skills, and reduction of problem behaviour was also studied. The interventions employed were prompt-based procedures (5), video modelling (4), and functional communication training (2). Social stories were components of two of the prompt studies.
3. Twenty eight items (62.2%) reported strong support for generalized main effects. All but two of them reported strong support for the main effect. The skills that generalized included academic and communication skills, interpersonal skills and personal responsibility, and reductions in problem behaviour. The majority of interventions were composite strategies with various forms of prompting and/or reinforcement strategies being used along with a range of other ABA methods (e.g., fading, scripts, task analysis, self-management, extinction, imitation).

In conclusion, almost two thirds of the 45 analyses reported strong support for generalized main effects. Studies reporting limited support for main effects were less likely to report generalization of those effects. No single intervention strategy stood out as superior in producing generalized effects across a range of targeted behaviours. All of the strategies used appeared to be successful, although composite strategies show the greatest promise. Note that these were composites of ABA approaches; none of the composite strategies combined ABA strategies with non-ABA strategies (e.g., prompts and facilitated communication). There does not appear to be a relationship between the level of support reported (i.e., none, limited, or strong), the strategies used, and the skills being generalized.