Discrete Trial Therapy

Description of the Strategy

Discrete trial therapy is a specific form of teaching that places emphasis on the instructor providing a structure, specific context, and pacing to a teaching interaction. It requires an active response from the learner and thus is different from lecture-style instruction. It is discrete in that the various components that comprise a teaching-learning interaction are specified and choreographed into a systematic and replicable interaction. Related parameters for discrete trial procedures include massed versus spaced practice, level and type of prompting for response emission and error correction, reinforcement parameters (such as schedule, type, and amount), physical set-up of the learning environment, precise selection of learning materials/ stimuli, intertrial interval duration, response selection and criteria for reinforcement (shaping parameters), and response generalization and maintenance. In contrast, most typical teaching/learning interactions are fluid in that many different stimuli are presented, and a wide range of responses are expected of the learner. In turn, teacher response to learner correct responding and incorrect responding may be variable in degree and type. Typical teaching lessons often have a theme and a set of goals, but the teaching/learning interaction is not highly choreographed, and moment-to-moment changes are the norm.

Research Basis

The research base for discrete trial learning is extensive because discrete trial is simply a format for basic trial-and-error learning, also known as “three-term contingency” or “ABC” of learning. These refer to the sequence of antecedent, behavior, and consequence that may be used to describe the conditions under which most learning occurs. The manipulation of each of these three variables, alone and in combination, has been the [Page 807]subject of thousands of research studies across human and nonhuman populations. Thus, the impact of these variables on learning has become a truism, and reference may be made to the laws of learning. However, while the basic and applied research base is extensive, because there are so many variants to each of the three components, research continues to flourish as more and more sophisticated questions are addressed, particularly with respect to learning for special populations.

Relevant Target Populations and Exceptions

As mentioned above, discrete trial therapy, given its basis in basic learning theory, has been applied extensively to both typical and atypical populations, reflecting a broad range of species and behavior topographies. This research has led to a depth of knowledge that has permitted direct applied application to human populations with special needs. The focus has tended to be with individuals with mental retardation and/or developmental disabilities. While such application has been occurring in a formal and broad manner since the early 1960s, a rapid increase was observed in the mid-1980s due to publication of a number of research outcome studies and program descriptions, all indicating previously unheard of treatment gains in children with autism using intervention programs incorporating discrete trial therapy as an essential component. While discrete trial therapy can be appropriately applied to both typical and atypical populations, its use for children with autism spectrum disorders has become pervasive within behaviorally oriented treatment programs and has found its way into nonbehavioral treatment programs although rarely labeled as discrete trial therapy under those circumstances. Thus, it is this breadth of use within the autism spectrum population that has created the term discrete trial therapy to connote its core importance and extensive application, in contrast to the more correct terms discrete trial training and discrete trial teaching. However, among the lay public, the terms discretes and discrete trials are also used, and often incorrectly, to indicate it is the full extent of the treatment program, rather than as simply a component (albeit an important one) of a treatment program.

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