SPED 8013 | Chapter 11: Positive Reinforcement


  • A response is followed immediately by the presentation of a stimulus
  • This stimulus change increases the future frequency of similar responses under similar conditions
  • The future increase in the behavior is the critical feature in defining reinforcement

Immediacy of Reinforcement

  • It is critical that the consequence is delivered immediately following the target response
  • Problem with delays to reinforcement
    • Other behaviors occur during the delay
    • The behavior temporally closest to the presentation of the reinforcer will be strengthened

Delayed Reinforcement

  • Does not necessarily reinforce the target behavior; rather influences it
  • Instructional Control/Rule-Governed Behavior
    • Rule: verbal description of a behavioral contingency (this rule based behavior allows verbal contingencies to influence behavior i.e., working and waiting for a paycheck)
    • Can allow delayed consequences to influence behavior

“Rule-governed Behavior”

  • Indicators:
    • No immediate consequence apparent
    • Response-consequence delay > 30 seconds
    • Large increase in frequency of the behavior occurs following one instance of reinforcement
    • No immediate consequence for the behavior exists (including no automatic reinforcement), but rule does

Superstitious Behavior

  • Occurs when reinforcement “accidentally” follows a behavior that did not produce the reinforcing consequence
    • Sports players who equate putting on a certain pair of socks with winning a game (leading to the “lucky socks” idea)
    • Skinner’s pigeon’s

The Role of Antecedent Stimuli

  • Caveat #1: Reinforcement does not increase behavior under all conditions
  • The temporal relation between:
    • Antecedent variables
    • Responses
    • Consequences
  • …is Important!
    • These Antecedent variables become discriminative stimuli (SDs)
    • Thus, the response is more likely to occur in the future in the presence of these stimuli
  • Caveat #2 Reinforcement depends on motivation
  • The Swill only signal the response if the individual is motivated to engage in the response
  • Motivating Operations (MOs)
    • Alter the reinforcing effectiveness of stimuli, and thus
    • Alter the momentary frequency of responses reinforced by those stimuli

The Discriminated Operant

  • AKA “The Three-Term Contingency”

Motivating Operations

  • Establishing Operations (EO)
    • Increases the effectiveness of a stimulus as a reinforcer
    • Often involves decreased access to the stimulus (deprivation)
  • Abolishing Operations (AO)
    • Decreases the effectiveness of a stimulus as a reinforcer
    • Often involves having increased access to the stimulus (satiation)

The Four-term Contingency

  • The consideration of MOs are important in relation to the three-term contingency

  • The S(discriminative stimulus) lets us know that SR+(reinforcement) is available and the MO (either in the form of an establishing or an abolishing operation) lets us know how valuable that Swill be.

Points About Reinforcement

  • Automaticity of reinforcement – Does a person have to be aware that a response is being reinforced for it to increase?
    • No! The effect is automatic.
  • Arbitrariness of the behavior selected–Are certain behaviors susceptible to reinforcement and others are not?
    • No! The only relevant property is the temporal relation between the response and the consequence

Automatic Reinforcement

  • Reinforcement that occurs independent of another person delivering it
  • The response itself produces the reinforcement
  • Examples:
    • Wiggling your leg during a boring lecture to stimulate yourself and stay awake
  • Note: This does not mean the behaviors are automatic (i.e. “reflexive”); rather that the consequences are delivered automatically.

Classifying Reinforcers

  • Unconditioned Reinforcers (AKA primary or unlearned reinforcers)
    • Function as reinforcers due to heredity/evolution
    • Do not require any learning history to become reinforcers
    • Examples: Food, water, oxygen, warmth, sexual stimulation, human touch (perhaps), etc.
  • Conditioned Reinforcers (AKA secondary or learned reinforcers)
    • Neutral stimuli that begin to function as reinforcers as a result of being paired with other reinforcers (either conditioned or unconditioned)
    • Examples: Yellow paper, sticker, tokens…

Generalized Conditioned Reinforcers

  • A type of conditioned reinforcer that has been paired with many conditioned and unconditioned reinforcers
  • Do not depend on a specific EO to be effective
  • Does not have to involve trading in, but often does (praise vs. points)
  • Examples: tokens, money

Reinforcers by Formal Properties

  • Edible reinforcers (food)
  • Sensory reinforcers (massage, tickles)
  • Tangible reinforcers (trinkets, toys)
  • Activity reinforcers (playing a game, recess)
  • Social reinforcers (physical proximity, social interaction)

Identifying Potential Reinforcers

  • It is important to identify reinforcers empirically
    • Staff, parents, teachers and even children themselves who report what they believe to be reinforcers are often wrong
  • Two strategies to use in tandem
    • Stimulus Preference Assessments
    • Reinforcer Assessments

Caveats Regarding Preference/Reinforcer Assessment

  • Preference changes over time
    • Evaluate frequently
  • Preference assessments do not identify the reinforcing effects of stimuli
    • Just because people prefer paper towels to hot-air hand dryers in public restrooms doesn’t mean they’ll work to earn paper towels!

Stimulus Preference Assessments

  • Method of determining
    • Stimuli a person prefers
    • Relevant preference values (high vs. low)
    • Conditions under which these preferences hold true
  • Three Categories
    • Asking about preferences
    • Observing the target person under free-operant conditions
    • Presenting various stimuli in a series of trial-based observations

Asking About Stimulus Preferences

  • Ask the target person
    • Open-ended questions
      • What would you like to work for?
    • Choice format
      • Would you rather work for things to eat or things to do?
    • Rank order format
      • Put these items/activities in order from which you’d like to work for most to which you’d like to work for least
  • Offering Pre-task choices
    • When you are finished working, you can play with Battleship, checkers, or the computer
  • Asking significant others
    • Ask caregivers to identify preferred stimuli

Asking about stimulus preferences is a relatively uncomplicated procedure, however there are problems:

  • Verbal reports may not correspond to actual behavior
  • High number of false positives

Free Operant Observation

  • Observing and recording what activities the target person engages in when he/she has unrestricted choice of activities
  • No response requirements
  • All stimuli available within sight and reach
  • Items are never removed
  • Can be contrived or naturalistic

Contrived Free Operant Observation

  • Just prior to observation, provide learner with non contingent exposure to each item (for sampling purposes)
  • Place all items in view and within reach
  • Observe for a set period of time and record the function of time target person engages with each stimulus item

Naturalistic Free Operant Observation

  • Conducted in everyday environments as unobtrusively as possible (e.g. during recess)
  • Observe for a set period of time and record the duration of time target person engages with each stimulus item/activity

Advantages of Free Operant Assessment

  • Less time consuming than some trial based methods of preference assessment
  • Less likely to produce problem behavior because preferred stimulus are never removed

Trial-Based Methods

  • General Procedure
    • Present selected stimuli to children in a series of trials
    • Measure approach (e.g. eye gaze, hand reach), contact (e.g. touch/hold), and/or engagement (e.g. interacting with stimulus)
    • Can categorize as high, medium, and low preference
  • Many Variations for Procedure

Trial-based METHOD 1: Single Stimulus Presentation

  • Present stimuli, one at a time, in random order and record target person’s reaction to it
  • Well suited to individuals who have difficulty in selecting among two or more stimuli

Trial-based METHOD 2: Paired Stimuli Presentation

  • Sometimes called “forced-choice” method
  • Present two stimuli simultaneously and ask the target person to choose one
  • Each stimulus is matched to every other stimulus in the set
  • Rank order from high, medium, and low preference

Trial-based METHOD 3: Multiple Stimulus Presentation

  • Extension of the paired-stimuli presentation
  • Present an array of 3 or more stimuli together
  • Two major variations:
    • With replacement:
      • Stimulus select remains in array in any subsequent trials
    • Without replacement:
      • Selected stimulus is removed from the array in subsequent trials (takes about half the time to complete the procedure, and is still fairly accurate)
  • Trial is begun with: Which one do you want the most?
    • Repeat several times

Guidelines for Selecting and Using Stimulus Preference Assessments

  • Monitor target person’s activities prior to assessment to be aware of any EOs that may affect results
  • Balance cost-benefit ration of procedures (time to do vs. level of confidence –accuracy vs. frequency)
  • When time is limited, use fewer stimuli in array
  • When possible, combine data from multiple assessment procedures

Reinforcer Assessment

  • A direct, data-based method in which
    • One or more  stimuli are presented
    • Following a target response, and
    • Observing whether an increase in responding occurs
  • Allows you to verify/confirm whether a stimulus functions as a reinforcer

Concurrent Schedule Reinforcer Assessment

  • Pit two stimuli against each other and observe which produces the larger increase in responding
  • Be aware of possible differences between relative and absolute reinforcement effects
  • Responses should require comparable response effort

Multiple Schedule Reinforcer Assessment

  • Two or more component schedules of reinforcement for a single response with only one component schedule in effect at a given time
  • An Ssignals the presence of each component schedule and is present while that component is in effect

Progressive-Ratio Schedule Reinforcer Assessment

  • Preferences may change when response requirements increase
  • Progressive-ratio schedules provide a framework for assessing relative effectiveness of a stimulus as reinforcement as response requirements increase
  • Response requirements are systematically increased over time until responding declines

9 Guidelines for Using Reinforcement Effectively

  1. Set an easily-achieved initial criterion for reinforcement
  2. Use high-quality reinforcers of sufficient magnitude
  3. Use varied reinforcers to maintain potent establishing operations
  4. Use direct rather than indirect reinforcement contingencies when possible
  5. Combine response prompts and reinforcement
  6. Reinforce each occurrence of the behavior initially
  7. Use contingent attention and descriptive praise
  8. Gradually increase the response to reinforcement ratio
  9. Gradually shift from contrived to naturally occurring reinforcers