Section I: Basic Behavior Components (A-B-C Model)

What is Behavior?

  1. Behavior serves two purposes: (1) to get something or (2) to avoid something.
  2. All behavior is learned.
  3. Behavior is an action that is observable and measurable.
    • Behavior is observable. It is what we see or hear, such as a student sitting down, standing up, speaking, whispering, yelling, or writing. Behavior is not what a student is feeling, but rather how the student expresses the feeling. For example, a student may show anger by making a face, yelling, crossing his arms, and turning away from the teacher. These observable actions are more descriptive than just stating that the student looks anxious.
    • Behavior is measurable. This means that the teacher can define and describe the behavior. The teacher can easily spot the behavior when it occurs, including when the behavior begins, ends, and how often it occurs. For example, “interrupting the teacher all the time” is not measurable because it is not specific. However, “yelling ‘Hey, teacher!’ 2-3 times each math period” is specific and measurable. Given the definition, even an outside observer would know exactly which behavior the teacher wants to change.
  4. Behavior has three components:
    A (Antecedents) ⇒ B (Behaviors) ⇒ C (Consequences).

Rather than occurring in isolation, behavior is preceded by an antecedent (trigger) that sets off the behavior and is followed by a consequence, or a reaction to the behavior. This process is easily remembered by the acronym ABC.

Antecedents (A):

Antecedents are events or environments that trigger behavior. They can happen immediately before a behavior or be an accumulation of previous events. Examples of immediate antecedent would be: A student walks into class crying because someone called her a name as she was walking down the hall. The antecedent was the name calling in the hallway.

Antecedent can also be a collection of events that have happened in the past that eventually explode into acting out behaviors. For example: A student is constantly bullied and teased by other students on the bus and after two weeks of this, one day the student stands up on the bus and begins fighting with the other students sitting around him. The ongoing bullying and teasing has finally accumulated and resulted in explosive and aggressive behavior by the young man being taunted.

Behavior can also be enhanced or impacted by setting events such as a lack of sleep, medication, hunger/thirst, etc. For example, the student who is on medication may be drowsy or sleepy in class and unable to perform tasks required by the teacher.

Behaviors (B):

Behavior, as noted above, is an action that is both observable and measurable. It should be described in a way that an outside observer can easily identify the action (behavior) in question.


Vague behavior: Sandy is being obnoxious during her science lab class.

  • What does obnoxious look like?
  • Describe an example of a more specific way to identify obnoxious behavior (i.e., hitting other students, talking out in class, texting on her cell phone).
  • All behaviors need to be observable (e.g., hitting, talking out, texting).
  • All behaviors need to be measurable (how many times, how often, length of time).

An observable and measurable behavior: Sandy hits her lab partner whenever he tries to work on his science lab report.

  • The behavior is hitting when the lab partner works on his science paperwork. See the difference?

Consequences (C):

A consequence is the response to the student’s behavior. Consequences are how people in the environment react to the behavior. When a student displays a certain kind of behavior, the teacher may “warn” or “ignore” the student. Warning, ignoring and reinforcing are some examples of consequences.

Here are some examples of the behavior chain (A⇒B⇒C):

Example 1

  • Antecedent: Teacher asks question.
  • Behavior: Student shouts out an answer without raising her hand.
  • Consequence: Teacher verbally reprimands student.

Example 2

  • Antecedent: Driver sees a stop sign.
  • Behavior: Driver stops the car at the intersection.
  • Consequence: Driver avoids a possible wreck and ticket.

Example 3

  • Antecedent: Mother asks child to pick up toys and put in toy box.
  • Behavior: Child picks ups toys and puts them into the toy box.
  • Consequence: Mother verbally praises child and gives him a cookie.

Further Understanding of Consequences: Reinforcement and Punishment

Consequences for behavior can impact the future of the behavior (i.e., increase or decrease the behavior). Pleasant consequences that increase the occurrence of future behavior are called reinforcements. Undesirable consequences that decrease the occurrence of future behavior are called punishments.


Reinforcement is any type of feedback or consequence that increases future occurrences of a behavior. An increase in the student’s behavior results from a reinforcement even if the teacher does not find the consequence or feedback reinforcing. In other words, a consequence is reinforcing based on an individual student’s response. What is reinforcing to one student may not be to another; therefore planning for behavior change must be individualized.

Positive reinforcement is when something is gained and it increases the occurrence of a behavior. An example would be if a student makes a 100 on a trial spelling test on Thursday, she would get free time. The student performs well on the future tests too. The student’s study behavior for their spelling test has increased due to earning free time on Fridays, which is the positive reinforcer.

Negative reinforcement is when something is taken away and it increases the occurrence of a behavior. An example would be if a student does not finish his homework, his parents tell him that he does not get to watch TV that night at home. The next time the student has homework, he finishes as soon as he can so that he will not miss out on his TV time at home. His homework completion is the behavior that has been reinforced with the loss of TV privileges as the negative reinforcer.

Reinforcement Example 1

  • Antecedent: Teacher says "Walk and talk quietly through the library.”
  • Behavior: Students walk quietly, but talk loudly to their friends through the library.
  • Consequence: Teacher says "Because the class did not follow directions about walking and talking quietly through the library, we will miss recess today.”
  • Future Behavior: Students remember to walk and talk quietly through the library in order to have recess. (Removal of recess is the negative reinforcer.)

Reinforcement Example 2

  • Antecedent: Student needs to use the restroom
  • Behavior: Student asks politely for restroom pass
  • Consequence: Student receives the restroom pass from the teacher
  • Future Behavior: Student remembers to ask politely for the pass in the future. (Gaining permission to take the hall pass and use the restroom is the positive reinforcer for asking politely to use the restroom.)

Reinforcement Example 3

  • Antecedent: Teacher instructs class during math class.
  • Behavior: Student yells out without permission.
  • Consequence: Student is reprimanded by the teacher as the class laughs (gains attention).
  • Future Behavior: Students yells more. (Gaining attention from other students in the class is the positive reinforcer for yelling out in class.)


Punishment is a type of consequence that decreases future occurrences of the behavior. If the student finds the consequence unpleasant or undesirable and decreases the occurrence of the behavior in the future, then it is punishment, even if the teacher or other students do not perceive the consequence as unpleasant.

Punishment Example 1

  • Antecedent: Teacher says "Walk in the hall."
  • Behavior: Student runs in the hall.
  • Consequence: Student is reprimanded by the teacher.
  • Future Behavior: Student does not run down the hall. (The punishment is being reprimanded and it decreases the running in the hall behavior.)

Punishment Example 2

  • Antecedent: Homework is due as class begins.
  • Behavior: Student forgets to turn in his homework.
  • Consequence: Student loses points on his homework grade.
  • Future Behavior: Student turns future homework in on time. (The punishment is loss of points, and it decreases the student forgetting to turn his homework in on time.)

Punishment Example 3

  • Antecedent: Teachers states it is time for silent reading.
  • Behavior: Students continue to talk.
  • Consequence: Class loses free time for drawing in the afternoon.
  • Future Behavior: Class reads silently when requested in the future. (The punishment is loss of free time for drawing and the class stops talking during silent reading time.)

Data Collection with Behavior Change:

It is possible to inadvertently reinforce or punish behavior when trying to do the opposite. Therefore, data collection is a critical component whenever you are trying to change behavior. Data enables you to objectively analyze what is happening and modify the intervention if necessary.

Here is an example of inadvertently reinforcing an inappropriate behavior.

  • Antecedent: Teacher asks the student to do a task
  • Behavior: Student yells “NO!”
  • Consequence: Student is sent to time out and avoids the task
  • Inadvertent Reinforcement: Student prefers sitting quietly over working so the student yells out more to avoid tasks.

Here is an example of inadvertently punishing a desired behavior.

  • Antecedent: Teacher asks for a student to do a task
  • Behavior: Student volunteers and performs the task
  • Consequence: Teacher calls the student to the front of the room to praise the student.
  • Inadvertent Punishment: Student is embarrassed and does not volunteer again.


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