12.1 Discrete-Trial, Free-Operant, and Naturalistic Teaching Arrangements
Key Takeaways
Discrete-trial teaching (DTT) breaks instruction into brief trials with a discriminative stimulus, a prompt if needed, the learner's response, a consequence, and an intertrial interval, which allows many learning opportunities in a short time.
In a free-operant arrangement, the learner can respond at any time without trial-by-trial cues, so rate and fluency can be measured and built, as in Precision Teaching timings.
Naturalistic teaching (incidental teaching, natural environment teaching, mand-model, naturalistic time delay, pivotal response treatment) follows the learner's interests and uses natural reinforcers within everyday activities.
Choose and blend arrangements based on the learner's current skills, the target, the motivating operations available, and the need for generalization.
The Arrangement Is a Clinical Decision
Task G.13 asks you to develop and implement acquisition procedures that are appropriate to the client's skills and intervention goals, naming discrete-trial, free-operant, and naturalistic arrangements. These are not competing philosophies; they are tools. Exam items describe a learner and a goal and ask which arrangement fits, or they describe a session and ask you to name the arrangement.
Discrete-Trial Teaching (DTT)
In discrete-trial teaching, instruction is divided into short, distinct trials. Each trial has five parts (Smith, 2001):
- Discriminative stimulus: a brief instruction or cue ("Touch cow," a flashcard).
- Prompt (if needed): delivered with or just after the SD, then faded across trials.
- Response: the learner's answer.
- Consequence: immediate reinforcement for a correct response; for an error, a planned error-correction procedure (for example, re-presenting the trial with a prompt).
- Intertrial interval: a short pause (a few seconds) before the next trial, which clearly separates trials.
Strengths: many learning opportunities per hour, precise control of prompts and stimuli, clear data on each trial, and efficient teaching of new discriminations (for example, receptive labels). Limitations: skills learned in DTT may not generalize to natural settings without planning, the learner responds only when cued (risk of prompt dependence and limited spontaneity), and adult-chosen reinforcers can lose value. Trials may be massed (the same target repeatedly) early in acquisition or interspersed (mixed with mastered targets) to maintain momentum and check discrimination.
Free-Operant Arrangements
In a free-operant arrangement, the learner can respond at any time, as often as they are able, without waiting for a trial-by-trial cue. Responding is limited only by the learner's own rate. Examples include a one-minute timing in which a student writes as many math facts as possible, a vocational task in which the learner assembles as many units as possible, and play sessions in which the learner manipulates toys freely while the instructor reinforces target actions as they occur.
Free-operant arrangements make rate meaningful, so they are ideal for building fluency (accurate and fast responding). Precision Teaching uses brief, repeated timings and charts the results on the Standard Celeration Chart (section 5.1). Fluent skills are more likely to be retained, to endure over longer periods, and to combine into more complex skills. In discrete trials, by contrast, the instructor controls the pace, so rate mostly reflects the instructor.
Naturalistic Teaching
Naturalistic (or naturalistic developmental behavioral) approaches teach within ordinary activities, follow the learner's interests, and use the natural consequence of the response as the reinforcer. Common procedures:
- Incidental teaching (Hart & Risley, 1975): arrange the environment so preferred items are visible but out of reach, wait for the learner to initiate, then prompt a more elaborate response before giving the item.
- Mand-model (Rogers-Warren & Warren, 1980): during an activity the learner is engaged in, the adult asks for a response (the "mand," such as "What do you want?") and models the answer if needed.
- Naturalistic time delay (Halle and colleagues): the adult waits expectantly at a moment when the learner needs something (for example, holding the coat by the door) to give the learner a chance to respond before prompting.
- Natural environment teaching (NET): a general term for teaching embedded in play and routines.
- Pivotal response treatment (PRT): developed by Koegel and colleagues; components include learner choice, interspersing maintenance and acquisition tasks, reinforcing reasonable attempts, using natural reinforcers directly tied to the response, and varying the materials.
Strengths: high motivation because the learner chooses the activity, strong generalization because teaching occurs in real settings with natural stimuli, and more spontaneous use of skills. Limitations: fewer learning opportunities per hour, which depend on the learner's motivation, and less control over stimuli, which can make difficult discriminations harder to teach.
Comparing the Arrangements
| Feature | Discrete-trial | Free-operant | Naturalistic |
|---|---|---|---|
| Who initiates | Instructor | Learner, within a set period | Usually the learner |
| Pace | Instructor-controlled | Learner-controlled | Follows the activity |
| Reinforcers | Often selected by the instructor | Often built into the task or delivered for target rate | Natural consequence of the response |
| Best for | New discriminations, precise prompting | Fluency and endurance | Generalization, spontaneity, manding |
| Main risk | Poor generalization, prompt dependence | Practicing errors fast if accuracy is low | Too few learning opportunities |
Choosing and Blending
- Learner skills: A learner who does not yet attend to instructional cues may start with naturalistic and play-based teaching; a learner who learns quickly with structure may benefit from DTT for new discriminations.
- Target: Mands depend on motivating operations, so they are best taught when the MO is present, often naturalistically. Receptive labels and complex discriminations often start in DTT. Math facts and reading benefit from free-operant fluency practice once accuracy is high.
- Generalization goals: Even when DTT is used for acquisition, plan probes and practice in natural routines.
- Data: Use trial-by-trial data in DTT, rate per minute in free-operant timings, and opportunity-based or probe data in naturalistic teaching.
A common blended day for a young learner includes short DTT blocks for new discriminations, naturalistic sessions for manding and play, and brief fluency timings for mastered academic skills.
Common Exam Traps
- Calling any table-top session DTT. If the learner initiates and the natural item is the reinforcer, it is naturalistic even at a table.
- Measuring rate in DTT. The instructor controls the pace; use accuracy per opportunity instead.
- Fluency timings before accuracy. Build accuracy first, then speed.
- Assuming naturalistic teaching means no structure. It is planned: the environment, prompts, and reinforcement are all arranged.
A child reaches toward bubbles on a high shelf. The therapist waits for the child to look at her, prompts "bubbles please," and blows bubbles when the child says it. Which arrangement is this?
Incidental teaching, because the child initiated and received the item they requested
Discrete-trial teaching, because the therapist delivered a prompt and a consequence
Massed-trial training, because the same request was practiced again in each trial
Free-operant teaching, because the child could respond at any time during the session
A student answers single-digit addition facts with 100% accuracy but takes almost 10 seconds per fact. Which arrangement best addresses the remaining problem?
Most-to-least prompting on each fact so the student never makes another error
Repeated one-minute free-operant timings that measure correct facts per minute
More discrete trials with a longer intertrial interval so the student can rest between facts
Incidental teaching during snack time, waiting for the student to request a math activity
In discrete-trial teaching, what is the main purpose of the intertrial interval?
To deliver a second, larger reinforcer for correct responding
To separate trials so each SD is clearly distinct from the last
To give the learner a chance to request a different instructional target
To allow time for an extinction burst to end before the next prompt
Sections you finish are checked off in the contents.