Discrete Trial Training (DTT) is a highly structured, one-on-one teaching method used extensively in applied behavior analysis (ABA) that systematically breaks down skills into smaller, teachable units. It is characterized by a precise sequence of events designed to facilitate learning and skill acquisition, comprising six essential components.
The precise and repetitive nature of DTT helps learners, especially those with autism spectrum disorder, acquire new skills efficiently by providing clear instructions and immediate feedback. Each "trial" is a single teaching opportunity, carefully structured to maximize learning and minimize errors.
Understanding the DTT Sequence
The efficacy of Discrete Trial Training stems from its systematic and consistent application of its core components, which are repeated numerous times across various settings and instructors to ensure mastery and generalization of skills.
Here's a breakdown of the six core components:
| Component | Description | Example |
|---|---|---|
| 1. Antecedent (Discriminative Stimulus - SD) | The instruction or cue that signals the availability of reinforcement for a correct response. It initiates the trial and sets the occasion for the desired behavior. | A therapist holds up a picture of a dog and says, "What is it?" or places a red block in front of the learner and says, "Touch red." |
| 2. Prompt | An additional cue or hint provided by the instructor to increase the likelihood of the learner giving a correct response. Prompts are used to ensure success and are systematically faded as the learner becomes more independent. | If the learner doesn't respond to "What is it?" (picture of dog), the therapist might say "D-o-g" (vocal prompt) or physically guide the learner's hand to touch the picture (physical prompt). |
| 3. Response | The specific behavior or action the learner performs in reaction to the antecedent and any given prompts. This is the skill being taught or measured. | The learner says "Dog" when shown the picture, or touches the red block when asked "Touch red." |
| 4. Consequence for a Correct Response | A reinforcer (e.g., praise, a preferred toy, a token) delivered immediately after a correct response. This increases the likelihood that the learner will repeat the desired behavior in the future. | Upon the learner saying "Dog," the therapist immediately says, "Great job saying 'dog'!" and gives them a high-five or a preferred snack. |
| 5. Consequence for an Incorrect Response | A neutral consequence or an error correction procedure applied immediately after an incorrect or no response. This is designed to prevent the reinforcement of errors and guide the learner towards the correct response. | If the learner says "Cat" instead of "Dog," the therapist might say "Oops," provide no reinforcement, and immediately represent the antecedent with a prompt ("Dog, say 'Dog'"). |
| 6. Inter-Trial Interval (ITI) | A brief pause between the end of one trial (consequence) and the beginning of the next trial (antecedent). This short break allows the learner to reset, and the instructor to record data and prepare for the next trial. | After the consequence for the previous trial, the therapist waits for 1-5 seconds, clears the table briefly, and then presents the next antecedent. |
The Flow of a DTT Session
A DTT session involves continuously repeating this sequence for a set number of trials or until a certain criterion is met. For example, an instructor might run 10 trials for identifying colors, then 10 trials for matching shapes, and so on. The rapid succession of trials provides numerous learning opportunities within a short period, allowing for intensive skill acquisition.
By breaking down complex skills into these discrete, manageable steps, DTT offers a highly effective and evidence-based approach to teaching a wide range of abilities, from foundational skills like imitation and receptive language to more complex social and academic behaviors. The systematic collection of data during the inter-trial interval allows practitioners to monitor progress, make data-driven decisions, and adjust teaching strategies as needed to ensure optimal learning outcomes for each individual.
