COMPONENTS OF DISCRETE TRIAL INSTRUCTION

The components of a discrete trial opportunity consist of several steps. The labels of these steps may differ from one author to another. The basic spirit of the command remains the same no matter what the label. In order to facilitate understanding, formal labels will be used with additional labels in parenthesis. Each trial should last between 5 and 30 seconds long. The teacher should provide a break between trials.

1. Discriminative Stimulus (SD) (Cue, Instruction, Command to attend)

SD is the stated adult direction that tells the student what you want them to do. The statement should be clear, brief and use specific wording. The same SD should be used for the same desired response. During generalization the SD will change.

2. Prompt (P) (Physical, Verbal, Model)

P is a planned teacher interaction to assist the student to choose the correct. Using a planned prompt in the sequence should be done when teaching a new skill. In order to prevent prompt dependence by the student the prompt should be removed or changed as the student demonstrates the requested skill.

3. Behavior (R) (Response, Command to perform)

The behavior is what the student does after the direction. (R) is the action that is demonstrated by the student following the (SD). The student should complete the adult request correctly.

4. Stimulus Reinforcer (SR) (Consequence, Feedback)

The SR is the feedback that is given to the student following either a positive or negative response. The reinforcer will shape either the negative or the positive student response.

If the student demonstrates the requested response independently without a prompt (SR+) then a positive reinforcer is provided for the student. If the student does not demonstrate the requested response correctly (SR-) then a pre-planned sequence pattern for correcting the wrong response is given by the adult. This pre-planned sequence may consist of sequencing, patterning or other shaping techniques to help the student learn the independent response.

5. Inter-trial Interval (ITI) (presentation wait time)

ITI is the time period of waiting between trials. The time interval provides the student with the information that one task has been completed and the next task is about to begin. The interval between trials is approximately 1 to 5 seconds.

Each student’s program or set of teaching lessons should take from 2 to 5 minutes per set. The total time for a DTI teaching sequence would be from 15 to 20 minutes in length. The student then would have a short break (5 to 15 minutes) between individual programs/lessons. Please remember that each student is an individual and time limits should be based on their individual needs and abilities.

Paul appears to be a student who could benefit from the DTI teaching method in specific skill areas. Paul responds to reinforcement and enjoys pleasing others. It appears that he really wants to communicate using verbal language, but may have been able to use his physical gestures to gain what he wanted. Information from the parents confirm this theory by stating that they would prefer to “help” him rather than let him become frustrated, upset and finally tantrum.