RBT Exam PrepThe short answer: Shaping builds a brand-new behavior by reinforcing closer and closer approximations of the target, raising the bar only when the current step is solid. Chaining links already-learnable steps into a sequence using a task analysis: forward chaining teaches from the first step, backward chaining from the last step, and total task presentation practices every step in every session. Your supervisor picks the method; you run the steps and take the data.
Shaping: rewarding almost-right
Shaping is for behaviors the learner cannot do at all yet. You start by reinforcing anything remotely close to the target, then gradually require closer approximations before delivering reinforcement. Teaching a child to say "water" might start with reinforcing any vocal sound, then sounds with a "w," then "wawa," then "water." Each step is a successive approximation.
The critical rule: only raise the requirement when the current approximation is happening consistently. Raise it too fast and the learner quits; never raise it and you reinforce mediocrity forever. This is differential reinforcement of successive approximations: reinforce the better versions, stop reinforcing the older ones. If the learner stalls, the exam answer is usually to go back to the last successful approximation, not to push harder.
Task analysis: the recipe card
Before you can chain a skill, you break it into steps with a task analysis: a detailed, ordered list of every component. Hand washing becomes: turn on water, wet hands, get soap, rub palms, rub backs, rinse, turn off water, dry hands. Each step must be small enough to teach and clear enough to score as correct or incorrect. The BCBA typically writes the task analysis; you implement it exactly as written.
The three chaining flavors
- Forward chaining: teach the first step to mastery, then the first two, then the first three, building from the front. The learner always starts the chain themselves, which builds independence early.
- Backward chaining: the trainer completes all but the last step, and the learner masters that final step first. Then the last two steps, then the last three. Powerful because the learner always finishes the chain and contacts the natural reinforcement at the end, like eating the sandwich they just made.
- Total task presentation: the learner attempts every step in every session, with prompts and assistance as needed. Best when the learner can already do many of the steps and just needs practice putting them together.
Shaping vs chaining: which one is it?
The exam loves making you choose between them, so here is the clean split. Shaping builds one behavior that does not exist yet by reinforcing closer and closer versions of it: the behavior itself is new, and you are sculpting it. Chaining connects steps the learner can already perform (or can learn individually) into a sequence: the pieces exist, and you are linking them. If the scenario describes reinforcing "wawa" on the way to "water," that is shaping. If it describes teaching the steps of brushing teeth in order, that is chaining. When a chain step itself is too hard, you shape that single step, then plug it back into the chain. The two procedures team up constantly in real programs, which is exactly why the exam tests whether you can tell them apart.
Quick-fire review
- Shaping = reinforce closer approximations, raise the bar gradually
- Task analysis = the step-by-step recipe the BCBA writes
- Forward = from step one; backward = from the last step; total task = all steps every time
- Stalled in shaping? Drop back to the last successful approximation
Last reviewed: October 7, 2026 against the BACB RBT 3rd edition task list.