C.3 Discrete-trial teaching
Discrete-trial teaching (DTT) breaks a skill into short, repeated learning opportunities, each with a clear beginning and end. The RBT presents a brief instruction, waits for the client's response, delivers the planned consequence, and records the result before starting the next trial. The supervisor chooses the targets, prompts, reinforcers and error-correction steps; the RBT carries them out exactly as written.
What the outline says
Task C.3 in content area C, Behavior Acquisition (19 of the 75 scored questions): "Implement discrete-trial teaching procedures."
What a discrete trial is
A discrete trial is one complete learning opportunity built on the three-term contingency: antecedent, behavior, consequence. It is called discrete because it has a definite start (the instruction) and a definite end (the consequence), which makes each trial easy to count and score.
Each trial has these parts:
- Discriminative stimulus (SD): the instruction and materials, such as saying "Touch cup" with a cup, spoon and plate on the table.
- Prompt (when the plan calls for one): extra help given with or just after the instruction, such as pointing to the cup.
- Response: what the client does within the response window the plan sets.
- Consequence: a reinforcer for a correct response, or the plan's error-correction step for an error or no response.
- Intertrial interval: a short pause before the next instruction, used to record data and reset materials.
Running a trial step by step
Before the session, review the program sheets and the last session's notes, and set out the materials and reinforcers the plan lists. If preferences change often, the plan may include a quick choice among a few items before each block of trials.
During each trial:
- Make sure the client is oriented to you or the materials.
- Give the instruction once, in the exact words the plan lists, in a clear and neutral voice.
- Prompt only as the plan directs. A 0-second prompt delay means the prompt comes with the instruction; a longer delay means you wait that long before prompting.
- If the client does not respond, wait out the response window without repeating the instruction; repeating it can teach the client to wait for several instructions.
- Deliver the consequence right away. For a correct response, give the planned reinforcer with behavior-specific praise ("You touched the cup!"). For an error or no response, follow the error-correction steps exactly.
- Record the trial, rearrange the materials if the plan calls for it, and start the next trial after a brief intertrial interval.
Delivering the reinforcer immediately matters. If you write data first and reinforce several seconds later, the reinforcer may follow some other behavior instead of the correct response. Reinforce first, then record.
Error correction and prompted responses
Error correction makes sure a correct response follows an error, so the error is not practiced. A common sequence is to present the instruction again with an immediate prompt, then present it once more without a prompt to check whether the client can now respond alone. Plans differ, so follow the steps written for that program.
Many plans reinforce independent responses more strongly than prompted ones, for example a preferred item for an independent response and praise only for a prompted response. This differential reinforcement helps move the client toward independence. Always record prompted responses as prompted, even when they are correct.
Arranging targets and materials
Massed trials present one target several times in a row. Task interspersal mixes in other targets, often mastered ones, which gives the client easy chances for reinforcement during hard work. Random rotation mixes targets in an unpredictable order. The supervisor decides which arrangement to use and when to change it.
In programs with several items on the table, change the position of the correct item between trials as the plan directs. If the client keeps choosing by position, such as always taking the card on the right, report it to the supervisor. That pattern means location, not the target, is controlling the response.
Data in discrete-trial teaching
Trial-by-trial data record every trial, usually during the intertrial interval. A typical summary is percentage correct: independent correct trials divided by total trials, times 100. If a client responds correctly without help on 15 of 20 trials, correctly with a prompt on 3, and incorrectly on 2, independent correct is 15 / 20 = 75%. Counting prompted trials as correct would give 90%, which overstates what the client can do alone.
Some plans use first-trial (probe) data instead: you record only the first response to each target at the start of the session, before any teaching. This shows what the client can do before any help that day. The supervisor decides when a target meets the mastery criterion, which may include several sessions or more than one staff member.
How DTT connects to other tasks
DTT uses prompting and prompt fading (C.7), discrimination training (C.6), and reinforcement and schedules (C.1). It differs from naturalistic teaching (C.4), which follows the learner's interests during everyday activities. Many programs use both: DTT gives many practice opportunities in a short time, and naturalistic teaching supports generalization (C.8).
Examples and non-examples
| Example | Non-example |
|---|---|
| The RBT says "Point to the quarter" once, the client points correctly within 5 seconds, the RBT immediately says "Yes, that's the quarter!" and gives a token, records the trial, rearranges the coins, and gives the next instruction. | The RBT says "Point to the quarter. Quarter. Which one is the quarter?" while the client looks away, then gives a token when the client points at any coin. |
| After an error, the RBT re-presents the instruction with an immediate model prompt, then presents it again without a prompt, as the plan's error correction says. | After an error, the RBT moves on to a new target and decides to drop the missed target from the program. |
Common mistakes
- Repeating the instruction when the client does not respond. Give it once, wait out the response window, then follow the plan's next step.
- Recording data before delivering the reinforcer. Reinforce immediately, then record.
- Scoring prompted responses as independent. Record the prompt every time, even if the response was correct.
- Adding unplanned help, such as glancing at or pointing to the correct card. Unplanned prompts change the procedure and make the data misleading.
- Changing the wording of the instruction from the plan. Different staff using different words gives the client mixed cues and makes the data hard to compare.
- Leaving the correct item in the same position on every trial, which lets the client respond by location.
How it's tested
Expect short scenarios about a single trial: naming its parts (SD, response, consequence, intertrial interval), picking the next step after an error or no response, spotting a mistake such as a repeated instruction or a delayed reinforcer, and calculating percentage correct from trial data. Read the plan details in the question carefully; the right answer is usually the one that follows the written plan exactly and leaves changes to the supervisor.
Practice questions for task C.3
10 of our 34 questions on this task. The rest are in the Behavior Acquisition practice sets and the mock exams.
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Question 1Which sequence shows the core parts of a discrete trial in the correct order?
Show answer
A: Instruction, learner response, consequence, intertrial interval. A discrete trial begins with a brief instruction (the discriminative stimulus), followed by the learner's response and then a consequence, with a short intertrial interval before the next trial. A prompt, when the plan calls for one, is given with or right after the instruction.
- B: The consequence follows the response; it cannot come before the instruction that starts the trial.
- C: A discrete trial starts with the instructor's instruction (the SD), and the response comes after it.
- D: The intertrial interval is the pause after the consequence, between one trial and the next.
Task C.3 · 40-hour curriculum section E
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Question 2After giving a client a reinforcer for a correct response, an RBT writes the data, waits about three seconds, and then gives the next instruction. What is this brief pause called?
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D: Intertrial interval. The intertrial interval is the short pause between the end of one trial (the consequence) and the instruction that starts the next. RBTs often use it to record data and reset materials.
- A: Latency is the time from an instruction to the start of the client's response, not the pause between trials.
- B: A prompt delay is the time between the instruction and the prompt within a trial.
- C: A limited hold is a time window in which a response must occur to be reinforced, not the gap between trials.
Task C.3 · 40-hour curriculum section E
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Question 3An RBT says "Point to dog" with three picture cards on the table. The client does not respond, so the RBT says "Point to dog. Point to dog. Dog!" What is the main problem with repeating the instruction?
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B: The client may learn to wait for repeated instructions. An instruction should be given once, then the RBT follows the plan's prompting or error-correction step if the client does not respond. Repeating it can teach the client that the first instruction does not matter.
- A: Discrete-trial instructions should be brief and clear; adding words makes the cue harder to follow, not easier.
- C: The client needs the cards in view to respond to a receptive instruction.
- D: Giving the reinforcer after no response would reinforce not responding.
Task C.3 · 40-hour curriculum section E
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Question 4Discrete-trial teaching is built on the three-term contingency. What are its three terms?
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B: Antecedent, behavior, consequence. The three-term contingency is antecedent, behavior and consequence. In a discrete trial these are the instruction (SD), the learner's response, and the reinforcer or error correction that follows.
- A: These are phases of an intervention, not the parts of a contingency.
- C: These are teaching steps for building independence, not the three-term contingency.
- D: The intertrial interval is a pause between trials; the third term of the contingency is the consequence.
Task C.3 · 40-hour curriculum section A · 40-hour curriculum section E
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Question 5A plan counts only independent correct responses as correct. In 20 trials, a client responds correctly without help on 15 trials, correctly after a prompt on 3 trials, and incorrectly on 2 trials. What is the percentage of independent correct responses?
Show answer
A: 75%. Divide independent correct trials by total trials and multiply by 100: 15 / 20 = 0.75, or 75%. Prompted correct responses are recorded separately when the plan counts only independent responses.
- B: 90% counts the 3 prompted responses as correct (18 / 20), which this plan does not allow.
- C: 83.3% divides by 18 instead of the 20 trials that were run (15 / 18).
- D: 10% is the percentage of incorrect trials (2 / 20).
Task C.3 · 40-hour curriculum section E
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Question 6A plan's error correction says: after an error, present the same instruction again with an immediate model prompt, then present it once more without a prompt. The client points to the wrong card. What should the RBT do next?
Show answer
B: Repeat the instruction with an immediate model prompt. The RBT carries out the error-correction procedure exactly as written: re-present the instruction with an immediate model so the client makes the correct response, then re-present it without a prompt.
- A: Moving on skips the error-correction steps the plan requires.
- C: Reinforcing an error, even with a smaller reinforcer, can strengthen errors, and the plan calls for correction.
- D: The plan does not call for a reprimand or a second unprompted guess; it calls for a prompted repeat.
Task C.3 · 40-hour curriculum section E · RBT Ethics Code 2.02
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Question 7What is the main purpose of an error-correction procedure in discrete-trial teaching?
Show answer
C: To make sure a correct response follows the error. Error correction gives the client help so that a correct response follows an error, which makes it less likely the error will be repeated. The exact steps are set by the supervisor in the plan.
- A: Error correction is a teaching step that leads to a correct response, not a punishment procedure.
- B: Error correction happens within the session, trial by trial; it is not a rule for ending sessions.
- D: Prompt levels are recorded in the data, but measuring them is not the purpose of error correction.
Task C.3 · 40-hour curriculum section E
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Question 8An RBT presents the same target, "Touch blue," for 10 trials in a row with no other targets mixed in. What is this arrangement called?
Show answer
A: Massed trials. Massed trials present the same target repeatedly in a block. Supervisors may use them early in teaching and then move to mixed or rotated targets.
- B: Task interspersal mixes other targets, often mastered ones, between trials of the new target.
- C: Random rotation mixes targets in an unpredictable order instead of repeating one target.
- D: Expanded trials gradually add more trials of other targets between presentations of the target.
Task C.3 · 40-hour curriculum section E
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Question 9A teen's discrete-trial plan says to mix mastered targets in with new targets. Which reason for this is most accurate?
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D: Mastered targets add easy chances for reinforcement. Mixing in mastered targets gives the learner frequent successes and reinforcement, which can support motivation and lower problem behavior during difficult work. It also gives practice that helps keep mastered skills.
- A: Mixing in mastered targets also helps keep those skills, and their purpose is not to fill time.
- B: New targets may still need prompts as the plan describes; mixing in other targets does not change that.
- C: Data for each target are recorded separately, so mastered targets do not change a new target's percentage.
Task C.3 · 40-hour curriculum section E
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Question 10A plan lists the instruction for a target as "Touch nose." Which way of presenting it follows the plan best?
Show answer
A: Say "Touch nose" once, clearly, when the client is attending. An instruction should be brief, clear and delivered as written, once, when the client is oriented to the RBT or the materials. Unplanned prompts and extra words change the procedure.
- B: Extra words make the instruction long and inconsistent with the plan.
- C: Pointing adds a gestural or model prompt that the plan did not call for.
- D: Giving the instruction when the client is not attending makes an error or no response more likely.
Task C.3 · 40-hour curriculum section E
Answer every question to see your score.
Key terms
| Discrete trial teaching | A structured teaching method that breaks skills into short, repeated learning trials, each with a clear instruction, the learner's response, a consequence, and a brief pause. |
|---|---|
| Discriminative stimulus | A stimulus in whose presence a behavior has been reinforced, and in whose absence it has not, so the behavior becomes more likely when the stimulus is present (SD). |
| Three-term contingency | The basic unit of operant behavior: an antecedent stimulus, the behavior that follows it, and the consequence that the behavior produces (often written A-B-C or SD-R-SR). |
| Intertrial interval | The brief pause between the consequence of one discrete trial and the presentation of the next trial's instruction, typically a few seconds. |
| Error correction | A planned procedure the RBT follows after an incorrect or missing response, usually prompting the correct response and then giving the learner another chance to respond. |
| Prompt | A supplementary stimulus added before or during a response to make the correct response more likely while a skill is being learned, meant to be faded later. |
| Mastery criterion | The preset level of correct, independent performance a learner must reach before a skill target is considered learned and moved out of acquisition. |
| Antecedent | An antecedent is an environmental condition or stimulus change that exists or occurs before a behavior. |
| Consequence | A consequence is a stimulus change that follows a behavior; depending on its effect, it can make that behavior more or less likely in the future. |
| Stimulus control | When a behavior reliably occurs (or occurs differently) in the presence of a particular antecedent stimulus because of a history of reinforcement in its presence. |
| Percentage | A percentage is a ratio expressed as parts per 100: the number of occurrences divided by the total, multiplied by 100. |
| Naturalistic teaching | Teaching that happens within the learner's everyday activities and routines, uses the learner's current interests and motivation, and relies on natural reinforcers. |
| Immediacy | Delivering a reinforcer right after the target behavior; the shorter the delay between a response and its consequence, the more effective reinforcement usually is. |
| Differential reinforcement | Reinforcing one behavior or response class while withholding reinforcement for others, usually problem behavior, so the reinforced behavior increases and the others decrease. |
| S-delta | A stimulus in whose presence a particular response has not been reinforced, so that response becomes less likely when the stimulus is present (written SΔ). |
| Satiation | A temporary decrease in how effective a reinforcer is, caused by recent contact with a lot of that reinforcer; it also makes behavior that produces it less likely. |
| Motivating operation | An environmental variable that temporarily changes how reinforcing a stimulus is and changes how often behavior that has produced that stimulus occurs. |
| Preference assessment | A preference assessment is a structured way of identifying which items or activities a person prefers, to find stimuli likely to work as reinforcers. |
| Procedural fidelity | Procedural fidelity is the degree to which an intervention is carried out exactly as written in the plan; it is also called treatment integrity or procedural integrity. |
| Prompt fading | Gradually and systematically reducing prompts so that the correct response comes under the control of the natural SD rather than the prompt. |
| Errorless learning | Teaching arranged with prompts and careful fading so that the learner makes few or no errors while acquiring a new skill. |
| Time delay | A prompt-fading procedure that inserts a pause between the SD and the prompt, starting at 0 seconds, so the learner can respond before the prompt is given. |
| Stimulus discrimination | Responding differently in the presence of different stimuli, for example making a response when the SD is present but not when another stimulus is present. |
| Tact | A verbal operant in which a person names or describes something they see, hear, smell, taste or touch; it is evoked by a nonverbal stimulus and maintained by social reinforcement. |
| Magnitude of reinforcement | How much reinforcement follows a response, such as the amount of an item, the length of access to an activity, or the intensity of the praise or stimulus. |
| Response prompts | Prompts that act on the learner's response, such as verbal instructions, gestures, modeling and physical guidance. |
| Modeling prompt | A response prompt in which the RBT, or another person or a video, demonstrates all or part of the correct response for the learner to imitate. |