Discrete Trial Instruction

Description of the Strategy

Discrete trial instruction is a teaching method guided by the core principles of applied behavior analysis and supported by extensive research. It is most frequently used to teach students with autism; however, examples of its application with other populations can be found in the research literature. In the most succinct form, a discrete trial begins with a teacher's request (verbal or nonverbal) for a student response. The request elicits an appropriate response by the student, and that response is followed by positive or corrective feedback from the teacher. Each “trial” is defined by the student's opportunity to respond with a “discrete” beginning and ending that typically lasts about 5 to 10 seconds. This method of instruction has been used to successfully teach a broad range of skills, including imitation, language, reading, math, and daily living activities (e.g., teeth brushing).

Figure 4 Direct Observation Decision-Making Flowchart

A discrete trial consists of four parts: (a) the teacher's cue or request, (b) the student's response, (c) the consequence, and (d) a short pause between the consequence and the next teacher request (the between-trial interval). It should be noted that it is generally accepted that individuals other than teachers [Page 1271]can be qualified to use discrete trial instruction. Paraprofessionals and parents can successfully implement discrete trial instruction after receiving sufficient training and practice.

A discrete trial begins with a teacher's cue, technically called a discriminative stimulus. Prior to the delivery of the cue, the teacher often gets the student's attention by saying his or her name and making eye contact or by saying, “Look” and simultaneously gesturing toward the instructional materials. This orienting request is then followed by the teacher's instruction or question and a presentation of the instructional materials (e.g., holding up a picture to be labeled). An instruction or question should be clear, concise, and given only once. Together, these conditions (materials and instruction) make up the discriminative stimulus.

Sometimes the teacher provides a preresponse prompt to ensure the student's correct and immediate response. This is particularly effective when the child lacks many of the component skills and is likely to make frequent errors. Often referred to as errorless teaching, preresponse prompts are added and gradually faded so that the child learns the new skill with few or no errors over the course of instruction. For example, the teacher may ask the student, “What color is this?” (while holding up a small blue car) and immediately provide the answer “Blue.” Across successive trials, the teacher then selects and uses one or more strategies to fade the prompt (e.g., waits progressively longer before providing the correct response, anticipating that the student will eventually preempt this prompt). It should be noted that a cue also could be nonverbal, such as when the teacher is attempting to teach the student to spontaneously request common objects. For example, the teacher may simply block access to a favorite toy, pause, provide an inquisitive look, and wait for the student to initiate. In this case, the discriminative stimulus involves a set of nonverbal cues that more closely approximate a natural situation in which “spontaneous” language is required for students to obtain an object beyond their reach.

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