Behavior Technician Training: Discrete Trial Teaching (DTT)

Discrete Trial Teaching (DTT)

Definition

  • DTT is a structured teaching technique based on applied behavior analysis (ABA) principles.
  • Skills are broken down into small, teachable parts, each taught independently.
  • Example: Teaching addition involves first teaching number identification, then counting skills, before teaching addition problems.

Important Aspects of DTT

  • Teacher-Directed Technique: The teacher initiates and controls each teaching opportunity.
  • Discriminative Stimulus (SD): Each trial begins with the teacher giving an instruction or question (the SD).
    • The SD is specific to the skill being taught (e.g., "Clap your hands" or "Do your puzzle").
  • Structured Environment:
    • Initially conducted in a highly structured environment to minimize distractions (e.g., private room, cornered-off area).
    • The environment becomes more natural as the child progresses.
  • Multiple Trials: Students are given multiple opportunities to practice a skill in a row.
    • Each learning opportunity is a trial, presented one after another.
  • Reinforcement:
    • Positive reinforcement is used (presentation of a stimulus following a response that increases the likelihood of that response).
    • The child's preference is considered when possible.
    • Reinforcement is always paired with praise.
    • If the behavior increases, the item functions as a reinforcer.

DTT and the Three-Term Contingency

The three-term contingency is composed of:

  • Antecedent: Structured environment, teacher and child at a desk, teacher gives instruction (SD).
  • Behavior: Child responds correctly or incorrectly.
  • Consequence: Teacher provides reinforcement for correct response or error correction for incorrect response.

Steps of DTT

  1. Gain the Child's Attention: Ensure the child is looking at you, sitting still, and not engaged in other behaviors.
  2. Present the SD: Give the instruction or question.
  3. Child Responds: Allow the child a moment to respond.
  4. Consequence:
    • Correct Response: Provide praise and a preferred item as a reinforcer.
    • Incorrect Response: Provide error correction (explained later).
  5. Intertrial Interval (ITI): A brief break (3-5 seconds) between trials to reset materials and collect data.

DTT Teaching Example

  • Skill: Answering the question, "How old are you?"
  • Antecedent: Child is looking at the teacher.
  • SD: Teacher asks, "How old are you?"
  • Behavior:
    • Correct Response: "I'm seven years old."
    • Incorrect Response: "I'm nine years old."
  • Consequence:
    • Correct Response: Praise and favorite toy.
    • Incorrect Response: Error correction.
  • Intertrial Interval: A new trial is started.

Errorless Teaching

  • A teaching procedure where a prompt for the correct response is provided immediately after the SD.
  • A prompt can be physical guidance, verbal cue, or visual cue.
  • Reduces initial errors and allows the child to practice the correct response from the start.
  • Particularly useful when first introducing a new skill.
Steps of DTT with Errorless Teaching
  1. The prompt is provided immediately after the SD.
  2. Reinforcement is still provided after the prompted response is completed.
  3. Prompting is faded systematically over time to promote independence.
Prompt Fading
  • Gradually reduce assistance. For example:
    • Fully prompt the child's hand to point, then prompt the wrist, then the elbow, and so on.
  • Reinforce responses requiring less and less assistance.
  • Eventually, only reinforce independent responses (differential reinforcement).

Error Correction

  • Used when a child makes an error, even after errorless teaching is implemented.
  • Consists of three steps:
    1. Correct the Error: Provide the correct response (demonstrate or help the child).
    2. Practice Trial: Represent the original SD give the child a moment to respond.
    3. Reinforcement: Provide praise and reinforcement (if appropriate; see below).

Reinforcement during Error Correction:

*In the practice trial, if the child responds correctly the teacher may:

  • Provide reinforcers: for correct independent responses during practice trials.
  • Not provide reinforcers: Only reinforce correct responses that do not require a practice trial.

Teaching New Skills

  • Massed Trials: Presenting the SD multiple times in a row to allow the child to practice the response repeatedly.
  • Intermixing: Interspersing a new SD with SDs the child can already respond to.
    • Gives the child opportunities to discriminate the new response from responses they already know.
  • Example Teaching "Ball":
    1. Hold up an object and ask, "What's this?". Immediately provide a verbal prompt "Say ball."
    2. Provide praise and a reward when the student says "Ball".
    3. Over the next trials, fade you prompts (e.g., Say, Ball).
    4. Provide praise when the student is able to label the object with less assistance.
    5. When the student can consistently label the object: Intermix trials by asking the student for responses she already knows.

General Guidelines for DTT

  1. Present the SD Only One Time:
    • Teaches the child to respond to instructions the first time they are presented.
    • Use a clear, directive voice.
    • Be consistent when presenting the SD, especially initially.
  2. Provide Reinforcers after Correct Responses:
    • Reinforcement strengthens the target behavior.
  3. Pair Verbal Praise with Reinforcers:
    • Use behavior-specific praise (e.g., "Good job, you touched blue!").

Summary of DTT

  • DTT breaks down skills into small steps and teaches each part independently.
  • A DTT trial involves a specific sequence of steps, which changes based on whether the child responds correctly or incorrectly.
  • Errorless teaching minimizes errors.
  • Error correction involves showing the correct response, represent the SD, and allowing the child to practice.