What is Discrete Trial Training?
Discrete Trial Training (DTT) is a structured ABA teaching method that breaks skills into small, clearly defined units and teaches them through repeated practice. Each "discrete trial" is a single, complete teaching opportunity with a clear beginning and end.
DTT is one of the most extensively researched teaching methods in autism intervention. Decades of studies have demonstrated its effectiveness for building a wide range of skills in children across the autism spectrum.
Structure of a trial
Every DTT trial has three parts:
- Discriminative Stimulus (SD) — the instruction or question that tells the child what to do. "Touch the ball." "What color is this?" "Show me big."
- Response — the child's answer or action. Can be correct, incorrect, or no response.
- Consequence — what happens immediately after the response. Correct responses receive reinforcement (praise, a preferred item, a token). Incorrect responses receive a neutral correction and another opportunity.
A brief pause — called the inter-trial interval (ITI) — separates one trial from the next. This gives the child a moment to reset before the next instruction.
How to run DTT at home
- Choose your goal and materials. Know exactly what skill you're targeting and have everything ready before you start.
- Get your child's attention. Make sure your child is oriented toward you before presenting the instruction.
- Present the instruction clearly. Short, consistent wording — the same every time.
- Wait for a response. Give your child about 3–5 seconds to respond before prompting.
- Deliver the consequence immediately. Reinforce correct responses right away. Neutrally correct errors and give another opportunity.
- Mark the inter-trial interval. A brief "okay" or pause signals the end of one trial before the next begins.
- Run 5–10 trials per goal. Then move on to another goal or take a short break before returning.
What skills to teach with DTT
DTT works best for foundational skills with clear correct/incorrect responses:
- Matching (objects, pictures, colors, shapes)
- Receptive identification (following directions, identifying named items)
- Expressive labeling (naming objects, pictures, actions)
- Imitation (copying actions, sounds, words)
- Early categorization and sorting
- Academic readiness (letters, numbers, colors)
Prompting in DTT
When a child doesn't respond correctly, prompt them to succeed rather than letting them sit with an error. Use the least intrusive prompt that produces the correct response. Common prompts in DTT: gestural (pointing to the correct answer), modeling (demonstrating), or verbal (giving a hint or partial answer).
Fade prompts systematically as the child's accuracy improves. The goal is always independent responding — the child performing the skill without any help.
Common mistakes to avoid
- Repeating the instruction multiple times. Say it once and wait. Repeating teaches children they don't need to respond immediately.
- Rushing through trials. The inter-trial interval is important. Don't stack trials so fast that your child can't process them.
- Inconsistent reinforcement. Reinforce every correct response during early learning. Missing reinforcers slows acquisition.
- Forgetting to vary the order. If you always present items in the same sequence, your child may learn the pattern, not the skill.
- Using the same reinforcer for too long. Reinforcers lose power through repetition. Rotate them to maintain motivation.
DTT vs. Natural Environment Teaching
DTT and Natural Environment Teaching (NET) are complementary, not competing. DTT builds skills efficiently in a controlled setting; NET generalizes those skills to the real world.
A best-practice approach typically uses both: DTT to establish new skills quickly, then NET to practice them in natural contexts so they transfer to everyday life. Most home programs should include elements of both every day.