Lesson 1.3 — Core Principles: Reinforcement, Punishment, Extinction, Stimulus Control, and Shaping

This lesson covers the five foundational principles of behavior analysis. These concepts are tested directly throughout every domain of the exam.

Reinforcement

Reinforcement is any consequence that increases the future frequency of a behavior. This is the most important principle in ABA. There are two types:

Positive Reinforcement (+R):

A stimulus is added following a behavior, and the behavior increases.

Example: A client completes a task, the RBT gives a high five, and the client completes tasks more often. The high five is added; the task completion increases.

Negative Reinforcement (-R):

A stimulus is removed following a behavior, and the behavior increases.

Example: A client complains about a difficult task, the task is taken away, and complaining increases. The task is removed; the complaining increases.

The single most common exam mistake: Students confuse negative reinforcement with punishment. Remember: both positive and negative reinforcement increase behavior. The difference is whether something is added (+) or removed (-). Punishment decreases behavior.

Unconditioned reinforcers are reinforcing without any learning history, such as food, water, warmth, and physical comfort. These are also called primary reinforcers.

Conditioned reinforcers acquire their reinforcing value through pairing with unconditioned reinforcers, such as praise, money, tokens, and grades. Also called secondary reinforcers.

Generalized conditioned reinforcers have been paired with many different reinforcers and work across many situations. Money is the best example. Tokens in a token economy are generalized conditioned reinforcers.

Factors that influence reinforcer effectiveness:

• Deprivation: the more deprived a person is of something, the more reinforcing it becomes
• Satiation: the more a person has had of something, the less reinforcing it becomes
• Immediacy: reinforcement delivered immediately after the behavior is more effective
• Contingency: reinforcement must be clearly contingent on the behavior to be effective
• Magnitude: larger reinforcers are more effective up to a point

Punishment

Punishment is any consequence that decreases the future frequency of a behavior. There are two types:

Positive Punishment (+P)

A stimulus is added following a behavior, and the behavior decreases.

Example: A client touches a hot stove, feels pain, and touches the stove less often. Pain is added; touching decreases.

Negative Punishment (-P)

A stimulus is removed following a behavior, and the behavior decreases.

Example: A client hits a peer, the tablet is taken away, and hitting decreases. The tablet is removed; hitting decreases.

Important note: In ABA, punishment is used carefully and ethically, and always in combination with reinforcement of alternative behaviors. Punishment alone does not teach what to do; it only suppresses behavior.

Extinction

Extinction is the process of withholding the reinforcer that was previously maintaining a behavior, resulting in a decrease in that behavior over time.

The key is that you must remove the specific reinforcer that has been maintaining the behavior. This requires knowing the function of the behavior first.

• If behavior is maintained by attention, withhold attention
• If behavior is maintained by escape, do not remove the demand
• If behavior is maintained by automatic reinforcement, extinction is more difficult because you cannot always remove sensory consequences

Extinction burst:

When extinction begins, most people expect the behavior to immediately decrease. It doesn’t; it typically gets worse first. This temporary increase in frequency, intensity, or duration is called an extinction burst. It is a predictable, normal reaction and does not mean the procedure is failing.

Spontaneous recovery:

After a behavior has been extinguished, it may temporarily reappear after a period of time without provocation. This is called spontaneous recovery. Continuing extinction procedures will typically cause rapid re-extinction.

Response variation:

During extinction, the topography (form) of the behavior may change, and new behaviors may emerge as the person tries different things to obtain the reinforcer.

Stimulus Control

Stimulus control exists when a behavior is more likely to occur in the presence of a specific antecedent stimulus because reinforcement has historically been available in the presence of that stimulus.

Discriminative stimulus (SD):

A stimulus in whose presence a behavior has been reinforced. The SD signals that reinforcement is available.

S-delta (SΔ):

A stimulus in whose presence a behavior has not been reinforced. The SΔ signals that reinforcement is not available.

Example: A child raises their hand in class and is called on by their regular teacher (SD) but not by the substitute teacher (SΔ). Over time, the child raises their hand more when the regular teacher is present.

Stimulus control is what makes training generalization necessary. A skill that only works in one setting, only in the presence of one SD, has not been fully taught.

Shaping

Shaping is teaching a new behavior by reinforcing successive approximations, responses that progressively resemble the target behavior more and more closely.

Shaping is used when the target behavior does not currently occur in the person’s repertoire. You cannot reinforce something that doesn’t happen, so you start by reinforcing whatever the person currently does that is closest to the goal, then gradually increase the requirement.

Steps in a shaping procedure:

1. Define the terminal behavior (the final goal)
2. Identify the person’s current behavior
3. Identify a starting point, something the person already does that is even slightly in the right direction
4. Reinforce the starting behavior until it is established
5. Gradually increase the criterion, reinforcing only responses that more closely approximate the target
6. Continue until the target behavior is achieved

Example: Teaching a child to say “cookie”:

• First reinforce any vocalization
• Then reinforce a /k/ sound
• Then reinforce “coo”
• Then reinforce “cookie”

Exam tip: Shaping is specifically about reinforcing successive approximations toward a target behavior. It is often confused with chaining (which teaches a sequence of behaviors) and prompting (which guides a behavior the person could potentially perform). Shaping is about gradually changing the form of the behavior itself.

Summary table

Principle	What happens	Effect on behavior
Positive reinforcement	Stimulus added	Increases
Negative reinforcement	Stimulus removed	Increases
Positive punishment	Stimulus added	Decreases
Negative punishment	Stimulus removed	Decreases
Extinction	Reinforcer withheld	Decreases (after burst)
Stimulus control	Behavior occurs in presence of SD	Context-specific increase
Shaping	Successive approximations reinforced	New behavior develops

Quiz 1.3 — Core Principles

20 questions · No time limit · Mix of definitions and scenarios