ABA glossary
Positive reinforcement
Also called SR+
Definition
A stimulus is added (or made stronger) right after a behavior, and as a result the behavior occurs more often in the future. The added stimulus is a positive reinforcer (SR+).
In plain words
"Positive" means added, not good. In positive reinforcement something appears after the behavior, such as praise, a token, a toy, attention, or a bite of a snack, and the behavior becomes more likely next time. What counts is the effect on behavior, not the intent. If a teacher's scolding follows calling out and calling out increases, the scolding worked as positive reinforcement even though nobody meant it as a reward.
Example from a session
Each time Jonah, 6, says "help" while stuck on a puzzle, the RBT helps right away and adds a quick "Great asking!" Over the week Jonah says "help" more often and grabs less. Help and praise were added after the response, and the response increased: positive reinforcement. The RBT delivers it immediately and only after the target response, as the plan says.
For BCBA candidates and supervisors
Designing positive reinforcement means choosing the reinforcer (from preference and reinforcer assessments), the schedule (often continuous at first, then thinned), immediacy, magnitude, and variety to delay satiation. Socially mediated positive reinforcement, such as attention or access to tangibles, is also a common maintaining variable for problem behavior, so the same principle explains both the treatment and the problem. When observing an RBT, a supervisor checks that reinforcers are delivered immediately, contingently, and at the planned magnitude, because loose delivery weakens the contingency.
Often confused with negative reinforcement, positive punishment
All three involve a stimulus change after behavior. Positive reinforcement adds a stimulus and behavior increases. Negative reinforcement removes a stimulus and behavior increases. Positive punishment adds a stimulus and behavior decreases. If a stem does not tell you whether the behavior went up or down, it has not given you enough to call it reinforcement.
Exam tip
Ask two questions in order: did future behavior increase or decrease, and was a stimulus added or removed? Increase plus added equals positive reinforcement. Ignore whether the stimulus sounds pleasant.
Can you spot positive reinforcement in a scenario?
Practice BCBA B.4 with exam-style questions and instant feedback.