Function of behavior
The reason a behavior keeps happening, defined by the reinforcing consequence that maintains it, such as attention, escape, tangible items or automatic reinforcement.
The function of a behavior is what the behavior gets for the person, described in terms of reinforcement. Behavior that keeps occurring is being reinforced, and identifying that reinforcer tells the team why the behavior persists. The common functions are usually grouped as social positive reinforcement (access to attention or to tangible items and activities), social negative reinforcement (escape from or avoidance of demands, people or situations), and automatic reinforcement (consequences produced by the behavior itself, not by another person).
Function is different from topography, which is what the behavior looks like. The same topography can serve different functions: one child hits to get an adult's attention while another hits to end a hard task. Different topographies can serve the same function: crying, dropping to the floor and saying "no" may all produce escape. A behavior can also serve more than one function.
Function matters because effective interventions are function-based. The supervisor uses functional assessment, such as indirect assessment, ABC data and functional analysis, to identify the function, then designs antecedent strategies, a replacement behavior that meets the same function, and extinction for the problem behavior. An intervention that does not match the function can fail or make the behavior worse.
The RBT helps by collecting accurate ABC and other data and by describing what happened before and after behavior in objective terms. Identifying the function is the supervisor's decision, not something the RBT concludes from a single observation.
Example and non-example
| Example | ABC data show that a client's screaming during reading is usually followed by the teacher removing the worksheet. The supervisor's assessment indicates the screaming is maintained by escape from demands. |
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| Non-example | "He hits because he is angry" or "she does it to be manipulative" describe inner states or intentions, not functions. A function names an environmental consequence that maintains the behavior. |
Don't confuse it with
| Operational definition | An operational definition describes what the behavior looks like so it can be measured, while the function describes why it continues. |
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| Antecedent | An antecedent is what happens before a behavior; the function is identified from the consequences that maintain it. |
Test yourself
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Question 1What is the main purpose of a functional behavior assessment (FBA)?
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D: To identify the function of a problem behavior so a plan can be designed. An FBA identifies the conditions that set off a problem behavior and the consequences that maintain it. Knowing the function lets the supervisor design an intervention that addresses why the behavior happens.
- A: Choosing new skills to teach is the purpose of a skills assessment.
- B: Finding preferred items is the purpose of a preference assessment.
- C: Medication decisions are made by medical professionals, not through an FBA.
Task B.3 · 40-hour curriculum section D
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Question 2Which list contains the four common functions of behavior?
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A: Attention, escape, tangible and automatic. Problem behavior is most often maintained by social attention, escape from something unpleasant, access to tangible items or activities, or automatic (sensory) reinforcement.
- B: Punishment, extinction and shaping are procedures or processes, not functions.
- C: These are measurement dimensions.
- D: These are parts of ABC recording and context, not functions.
Task B.3 · 40-hour curriculum section D · Task D.1
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Question 3Two clients both bite their hands. One does it mainly when given hard tasks; the other does it mainly when alone with nothing to do. What does this show?
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B: The same form of behavior can serve different functions. Function depends on the conditions that set off and maintain behavior, not on its form. That is why functional assessment is needed before a plan is written.
- A: Hand biting during hard tasks suggests a different function for that client.
- C: The plan depends on function, so behaviors that look alike may need different plans.
- D: Behavior with the same form can have different functions, so form alone does not show function.
Task B.3 · 40-hour curriculum section D · Task D.1
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On the RBT exam
This term belongs to task D.1 Functions of behavior in content area D, Behavior Reduction, which is 14 of the 75 scored questions.