2026 RBT Exam Prep Course

Lesson 1.1: Behavior, Environment, and the Three-Term Contingency

What Is Behavior?

Behavior is anything a person does that can be observed, repeated, and measured.

Crying, writing, running, saying “juice.”

Thinking and feeling exist, but ABA works with what can be seen and counted.

If two independent observers could watch the same event and agree on whether it happened, you have a behavior stated in observable and measurable terms.

What Is the Environment?

Environment is everything a person can contact through the senses:

  • Sights
  • Sounds
  • Textures
  • People
  • Instructions
  • Temperature

In ABA, we change behavior by changing the environment, not by appealing to willpower.

The Three-Term Contingency

The three-term contingency is the basic unit of analysis in ABA.

Every behavioral event can be broken into:

Antecedent (A)

What happens right before the behavior.

An instruction, the sight of a toy, a demand being placed.

Behavior (B)

The observable action.

Consequence (C)

What happens right after the behavior.

Consequences determine whether the behavior becomes more or less likely in the future.

Example

  • Antecedent (A): The RBT says, “Touch your nose.”
  • Behavior (B): The learner touches his nose.
  • Consequence (C): The RBT delivers praise and a token.

Because the consequence was reinforcing, nose touching on instruction becomes more likely.

Operational Definitions

Operational definitions turn vague labels into measurable descriptions.

  • “Tantrum” is a label.
  • “Any episode of crying, dropping to the floor, or kicking that lasts at least 30 seconds” is an operational definition.

The test for a good definition:

A substitute RBT who has never met the client could read it and collect the same data you would.

Subjective vs. Observable Descriptions

Words That Signal a Subjective, Unusable Description

  • Frustrated
  • Defiant
  • Rude
  • Anxious
  • Manipulative
  • Lazy
  • Upset

Words That Signal an Observable Description

  • Hits
  • Throws
  • Says
  • Walks away
  • Tears
  • Screams at a volume audible from the next room

Quiz 1.1 (15 questions)

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