Module 6: Positive Reinforcement

Foundations of Positive Reinforcement

  • Principle vs. Strategy:

    • Reinforcement is not a strategy, tactic, or intervention created by practitioners.
    • Reinforcement is a fundamental principle of behavior and represents the most widely used principle within applied behavior analysis (ABA).
    • Practitioners such as Registered Behavior Technicians (RBTs) and Board Certified Assistant Behavior Analysts (BCaBAs) rely heavily on this core behavioral principle.

  • Definition of Positive Reinforcement:

    • Positive reinforcement occurs when an individual engages in a behavior, which is immediately followed by the addition of a stimulus change, resulting in an increase in the future frequency or likelihood of that behavior occurring under similar conditions.
    • Terminology breakdown:
    • Positive: Refers specifically to the addition or presentation of a stimulus change to the environment following the response.
    • Negative: Refers to the removal or subtraction of a stimulus change from the environment following the response.
    • Reinforcement: Signifies that the consequence increases the future occurrence, frequency, or probability of the behavior.

  • Illustrative Examples of Positive Reinforcement:

    • Example 1 (Tacos):
    • Behavior: Mowing the lawn.
    • Immediate Consequence: Husband purchases tacos as a thank-you gesture.
    • Effect: Future occurrences of mowing the lawn increase.
    • Analysis: The tacos serve as the reinforcer. Positive reinforcement is demonstrated because tacos were added to the environment (positive\text{positive}) and future lawn-mowing behavior increased (reinforcement\text{reinforcement}).
    • Example 2 (Electric Toothbrush):
    • Behavior: A child brushes his teeth independently.
    • Immediate Consequence: Parent immediately presents a new electric toothbrush.
    • Effect: Independent toothbrushing behavior increases in the future.
    • Analysis: The electric toothbrush serves as the reinforcer, driving the future increase in independent toothbrushing.
    • Example 3 (Plant Cuttings and Gratitude):
    • Behavior: A coworker assists in completing a report prior to the deadline.
    • Immediate Consequence: Expression of gratitude (verbal thank-you) and presentation of plant cuttings.
    • Effect: Coworker assists with writing reports more frequently in the future.
    • Analysis: Verbal gratitude and plant cuttings served as the reinforcers that increased future report-writing assistance.

Reinforcer vs. Reinforcement and Behavioral Mechanisms

  • Conceptual Distinction:

    • Reinforcement: The underlying principle of behavior describing the functional relation between a response, a stimulus change, and a subsequent increase in future responding.
    • Reinforcer: The specific stimulus or stimulus change presented as a consequence following the behavior (e.g., tacos, electric toothbrush, plant cuttings, ice cream, cash).

  • Temporal Direction of Behavioral Effects:

    • A reinforcer does not affect the specific response instance that it immediately follows, as that response instance has already occurred in the past.
    • Reinforcers operate exclusively on future responding, altering the functional probability of similar responses under similar conditions.
    • Demonstration: Receiving tacos for mowing the lawn for the very first time could not have caused that initial instance of lawn mowing. Instead, contacting that reinforcing consequence increased all subsequent instances of lawn mowing.

  • Automaticity of Reinforcement:

    • Individuals do not need to understand, be aware of, or verbally articulate the functional relation between their actions and reinforcing consequences for reinforcement to operate effectively.
    • Reinforcement functions automatically through direct contact with behavior-stimulus contingencies.
    • Classroom Demonstration of Unconscious Shaping:
    • Students deliver attention (SR+S^{R+}) whenever a teacher stands on the right side of the classroom.
    • Students lower their heads, write, or look at their phones (withhold attention) whenever the teacher moves to the left side.
    • Outcome: The teacher unconsciously shifts to standing on the right side of the classroom significantly more often in the future.
    • Analysis: Student attention functions as a reinforcer, increasing the teacher's right-side standing behavior without the teacher's conscious awareness or verbalization of the contingency.

Immediacy of Reinforcement and Rule-Governed Behavior

  • The Rule of Immediacy:

    • The response that is temporally closest (occurs nearest in time) to the presentation of the reinforcer will be strengthened by that presentation.
    • Risk of Delayed Reinforcement: Delaying reinforcer delivery risks inadvertently reinforcing unpredicted or unwanted intermediate behaviors that occur during the delay interval. Every second matters during reinforcer delivery.

  • Direct vs. Indirect Effects of Consequences:

    • Delayed consequences do not reinforce behavior directly.
    • Behaviors occurring long before a delayed consequence are mediated through instructional control and rule-governed behavior.

  • Rule-Governed Behavior:

    • Definition: Behavior controlled by a rule, which is a verbal description of an environmental behavioral contingency.
    • Function: Enables human behavior to come under the indirect control of remote or indirect consequences without requiring direct, firsthand experience with every environmental contingency.
    • Indicators of Rule-Governed Behavior:
    • Absence of an immediate consequence following the behavior.
    • The response-consequence delay is greater than 30 seconds30\,\text{seconds}.
    • Behavior change occurs without direct contact with reinforcement (e.g., a student completes homework daily throughout the week prior to receiving a weekend reward).
    • A substantial, immediate increase in behavior occurs following a single instance of reinforcement or rule presentation.
    • No empirical consequence actually exists, but the verbal rule exists and controls behavior (e.g., engaging in specific lifelong rituals or actions based on religious beliefs and non-empirical spiritual contingencies).
    • Example:
    • Rule: "If you complete your homework every day from Monday through Friday, we will go to your favorite restaurant on Saturday."
    • Mechanism: The student completes homework on Monday without contacting immediate reinforcement that day, governed strictly by the verbal contingency statement.

The Three-Term Contingency and Discriminative Stimuli

  • Two-Term Contingency:

    • Composed of a Response (RR) followed closely in time by a Reinforcing Stimulus (SR+S^{R+}):     Two-Term Contingency: R→SR+\text{Two-Term Contingency: } R \rightarrow S^{R+}
    • Examples:
    • Kids run to the ice cream truck and pay (RR) →\rightarrow receive ice cream (SR+S^{R+}).
    • Opening an envelope (RR) →\rightarrow receiving cash (SR+S^{R+}).

  • Antecedents and Stimulus Control:

    • Reinforcement alters the function of environmental stimuli that immediately precede behavior.
    • Environmental stimuli present prior to behavior become associated with the availability of reinforcement, establishing stimulus control.
    • Examples of Discriminative Antecedents:
    • Ice cream truck music signaling ice cream availability.
    • Restaurant logos/signs signaling meal availability.
    • A spouse asking, "Would you mind mowing the grass?" signaling that tacos will likely follow.

  • Three-Term Contingency (Discriminated Operant):

    • Incorporates the Discriminative Stimulus (SDS^D), establishing a three-term functional unit:     Three-Term Contingency: SD→R→SR+\text{Three-Term Contingency: } S^D \rightarrow R \rightarrow S^{R+}
    • Discriminative Stimulus (SDS^D): An antecedent stimulus present in the environment that signals that a specific response will access reinforcement based on a history of reinforcement.
    • Example 1 (Ice Cream Truck):
    • Discriminative Stimulus (SDS^D): Ice cream truck sound plays.
    • Response (RR): Run to the ice cream truck and pay money.
    • Reinforcer (SR+S^{R+}): Access to ice cream.
    • Effect: Increases future running to the truck upon hearing the truck sound.
    • Example 2 (Mail):
    • Discriminative Stimulus (SDS^D): Arrival/presence of mail in the mailbox.
    • Response (RR): Opening the mail.
    • Reinforcer (SR+S^{R+}): Access to cash contained inside.
    • Effect: Increases future mail-opening behavior upon mail delivery.

Motivating Operations and the Four-Term Contingency

  • Motivating Operations (MOs):

    • Environmental variables that temporarily alter both the value of a consequence and the current frequency of behaviors associated with that consequence.
    • Dual Effects of MOs:
    • Value-Altering Effect: Temporarily increases or decreases the reinforcing effectiveness of a specific stimulus.
    • Behavior-Altering Effect: Temporarily increases or decreases the current frequency of all behaviors that have historically produced that specific stimulus.

  • Types of Motivating Operations:

    • Establishing Operation (EO):
    • Increases the reinforcing effectiveness of a stimulus (value-altering effect).
    • Increases the current frequency of behavior that yields that stimulus (behavior-altering effect).
    • Taco Example (EO): Starving after going all day without food →\rightarrow increases taco reinforcing value →\rightarrow mows grass rapidly.
    • Ice Cream Example (EO): Extreme hot weather and sweating →\rightarrow increases cold ice cream reinforcing value →\rightarrow runs faster to the truck and purchases more ice cream.
    • Mail Example (EO): Reading a social media post stating local mortgage lenders are sending cash via mail →\rightarrow increases cash reinforcing value →\rightarrow opens incoming mail immediately.
    • Abolishing Operation (AO):
    • Decreases the reinforcing effectiveness of a stimulus (value-altering effect).
    • Decreases the current frequency of behavior that yields that stimulus (behavior-altering effect).
    • Taco Example (AO): Satiated after eating tacos the previous night, a huge breakfast, and a large lunch →\rightarrow decreases taco reinforcing value →\rightarrow declines or delays lawn mowing.
    • Ice Cream Example (AO): Freezing weather and active snowfall while wearing gloves, mittens, and a scarf →\rightarrow decreases ice cream reinforcing value →\rightarrow stays seated on a park bench when the ice cream truck sound plays.

  • Four-Term Contingency:

    • Incorporates motivating operations into the discriminated operant model:     Four-Term Contingency: MO (EO or AO)→SD→R→SR+\text{Four-Term Contingency: } MO \text{ (EO or AO)} \rightarrow S^D \rightarrow R \rightarrow S^{R+}

Automatic Reinforcement and Sensory Functions

  • Dual Usage of Automatic Reinforcement in ABA:

    1. Non-Socially Mediated Contingencies:
    • A behavior-stimulus change relation that occurs completely independent of social mediation or the actions of another person.
    • Examples: An individual sitting alone listening to music; scratching an itch to alleviate discomfort (negative reinforcement).
    1. Unexplained Behavior Maintenance:
    • Descriptive label used when a behavior persists in the total absence of any known or observable external reinforcer, often assumed to produce internal sensory stimulation or relieve internal discomfort.

  • Clinical Practice Recommendation:

    • Use the term automatic reinforcement when describing behavioral functions maintained without social mediation.
    • Reserve the term sensory function strictly for instances where objective, empirical functional analyses confirm that the response is directly maintained by accessing or escaping specific sensory input.

Classifications and Categories of Reinforcers

  • Classification by Origin (Conditioning Status):

    • Unconditioned Reinforcers (Primary Reinforcers):
    • Stimuli that function as reinforcers from birth without any prior learning history or conditioning.
    • Examples: Food, water, oxygen, sexual stimulation.
    • Conditioned Reinforcers (Secondary Reinforcers):
    • Previously neutral stimulus changes that acquired reinforcing properties through pairing with unconditioned or conditioned reinforcers.
    • Examples: Verbal praise, high fives, token economies, money, favorite restaurants, specific peers.
    • Generalized Conditioned Reinforcers:
    • A specific type of conditioned reinforcer that has been paired with numerous unconditioned and conditioned reinforcers.
    • Does not depend on a specific establishing operation or motivational state to be effective.
    • Example: Money (universally exchangeable for endless primary and secondary reinforcers).

  • Classification by Formal Properties:

    • Edibles: Consumable food items and beverages (e.g., chips, candies, crackers, drinks, salad).
    • Sensory: Physical sensory input (e.g., vibration, tactile stimulation, flashing/sparkling lights, bright or dim lighting, music).
    • Tangibles: Physical objects and items (e.g., trinkets, stickers, toys).
    • Activities: Engagement in actions or events (e.g., playing soccer, rock climbing, visiting a playground, attending events).
    • Social: Interpersonal interactions (e.g., high fives, verbal praise, attention, physical proximity, hugs, handshakes).

The Premack Principle

  • Conceptual Definition:

    • Commonly known as Grandma's Law or Grandma's Rule ("You cannot have dessert until you eat your vegetables").
    • States that making access to a high-probability (high-frequency / preferred) behavior contingent upon the completion of a low-probability (low-frequency / non-preferred) behavior reinforces the low-probability behavior.

  • Mechanism of Action:

    • The opportunity to engage in the high-probability response functions as a reinforcer for the execution of the low-probability response.
    • Leads to an increase in the future rate and occurrence of the low-probability response.

  • Applied Examples:

    • Example 1 (Vegetables and Cake):
    • Low-Probability Behavior: Eating vegetables.
    • High-Probability Behavior: Eating cake.
    • Contingency: Cake consumption is granted strictly contingent upon eating vegetables first.
    • Example 2 (After-School Routine):
    • Problem: A child plays video games and talks to friends immediately after school, making subsequent homework completion extremely difficult to evoke.
    • Intervention: Reverse the contingency sequence.
    • Low-Probability Behavior: Completing homework assignment.
    • High-Probability Behavior: Playing video games and socializing with peers.
    • Contingency: Access to video games and peers is granted strictly contingent upon successful completion of homework.
    • Outcome: Homework completion increases substantially in the future.