ABA glossary
Most-to-least prompting
Also called decreasing assistance
Definition
A prompting procedure that starts with the most intrusive prompt planned for the skill and reduces help across trials or sessions as the learner succeeds.
In plain words
Most-to-least (decreasing assistance) starts with enough help to make a correct response almost certain, often full physical guidance, then steps down through less help, such as partial guidance, a model, or a gesture, until the learner responds independently. The learner makes few errors along the way, which suits new skills and learners for whom errors lead to frustration or problem behavior. Moving to a less intrusive level usually depends on a set number of correct responses at the current level.
Example from a session
Kai is learning to wash his hands. The program says to start with full physical guidance for each step, then move to partial physical guidance when the data meet the plan's criterion for that level, then to gestural prompts. The RBT follows the current level for all steps, records the prompt level used, and moves to the next level only when the data meet the written criterion.
For BCBA candidates and supervisors
Most-to-least is an errorless-learning approach; it is often the better choice for early learners, for chained motor tasks, and when errors could be dangerous. Its risks are slow fading and prompt dependence, so analysts set clear criteria for fading and watch for learners who wait for help. Research comparisons with least-to-most are mixed: least-to-most can be more efficient for learners who already have some of the skill, so analysts choose based on the learner's history and data.
Often confused with least-to-most prompting, graduated guidance
Most-to-least starts with the most help and fades it over trials or sessions. Least-to-most starts with the least help on each trial and adds more only if the learner does not respond correctly. Graduated guidance adjusts physical help moment to moment within a response rather than stepping through fixed levels.
Exam tip
If the stem describes starting with full physical help and reducing it as the learner improves, it is most-to-least. If it describes waiting first and adding help only after errors or no response, it is least-to-most.
Can you spot most-to-least prompting in a scenario?
Practice RBT C.7 with exam-style questions and instant feedback.