Primus Article 3

Journal of Speech and Hearing Research

  • Volume: 28

  • Pages: 539-547

  • Date: December 1985

  • Authors: Michael A. Primus, University of Wyoming; Gary Thompson, University of Washington

Introduction

  • Purpose of the Study: Evaluate the relationships between young children’s response behavior and two components of an operant conditioning paradigm:

    • Discriminative Stimulus (DS)

    • Reinforcing Stimulus (RS)

Experiment I

  • Subjects: Normal 1-year-olds

  • Objectives: Measure response performance as a function of intensity and complexity among three DSs.

    • Findings: No significant differences in conditioning rate, habituation, or consistency of the conditioned response concerning variable properties of the DS.

Experiment II

  • Subjects: Normal 2-year-olds

  • Objectives: Examine response performance based on modifications in the RS, specifically:

    • Reinforcement Schedule

    • Reinforcement Novelty

  • Results:

    • Subjects on a variable-ratio schedule and subjects on a 100% reinforcement schedule exhibited equivalent response habituation and consistency.

    • Subjects with novel RSs showed significantly greater response recovery than those with familiar RSs.

Comparison Between 1- and 2-Year-Olds

  • Findings:

    • Both groups had similar rates of conditioning and response consistency.

    • However, 2-year-olds habituated more rapidly than 1-year-olds.

Operant Conditioning Framework

  • Definition: Operant conditioning is utilized to strengthen a specific behavior of the subject by making it contingent on a positive reinforcer.

  • Components of the Operant Discrimination Paradigm:

    1. Discriminative Stimulus (DS): Signals availability of a reinforcer.

    • Examples:

      • Pure-tone stimuli: Establish frequency-specific auditory thresholds.

      • Speech stimuli: Assess complex processing skills.

    1. Response: Mode of the subject’s response.

    2. Reinforcing Stimulus (RS): Facilitates the evaluative process to maximize test efficiency and validity.

Visual Reinforcement Audiometry (VRA)

  • Description: An operant discrimination procedure using an animated toy animal as a single reinforcer with a distinct head turn response criterion.

  • Initial Findings:

    • Demonstrated robust responsivity in infants aged 12 to 18 months.

    • Effective for assessing skills in infants over 5 months of age.

  • Applications:

    • Evaluating normal auditory processes including:

      • Sensitivity thresholds

      • Speech discrimination abilities

      • Binaural fusion

      • Frequency selectivity

  • Adaptations: VRA adapted to assess visual abilities and expanded data on infant speech perception.

Justification for VRA

  1. Extensive experimental background providing a strong data base for modifications.

  2. Many auditory laboratories equipped to use VRA.

  3. Simple obtainability of VRA instruments.

  4. Strong initial influence on response behavior of children, despite rapid habituation.

  5. Techniques from classical psychological research can delay habituation through modification of the reinforcer.

Experiment I - Method

  • Design: Tested conditioned response behavior in children based on intensity and complexity of auditory DS.

  • Objective: Examine the relationship between DS properties and response behavior, which affects interpretation of audiometric findings.

Experiment II - Method

  • Subjects: Children aged 1 year and 2 years from a subject pool.

  • Inclusion Criteria:

    • Normal hearing and visual skills

    • No major developmental problems or history of chronic ear issues

    • Limited exposure to operant assessments

Discriminative Stimuli Used

  • Types:

    1. 1500 Hz warble tone

    2. Complex noise band pass (CNBP) with primary energy between 500 and 2000 Hz.

  • Calibration: Sensitivity thresholds measured prior to evaluation using Bruel & Kjaer equipment.

  • Instrumentation: Includes standard audiometer and a lighted animated toy as reinforcer housed in a black Plexiglas box.

Trial Schedule for Experiments

  • Phase I (Training): Conducted training trials followed by randomized stimulus and control trials.

  • Phase II: Investigated conditioning criterion and habituation criterion.

Results - Experiment I

  • Conditioning Rate: Variation in DS properties did not affect conditioning rate (F(2,33)=0.26, p>0.05).

    • Majority (32/36) satisfied conditioning criteria following two trials.

  • Habituation:

    • Habituation scores varied but did not show significant differences among groups.

    • Average scores:

      • Group 1 (50 dB CNBP): 31.3 (SD=15.09)

      • Group 3 (50 dB warble): 40.4 (SD=13.06)

      • Group 2 (25 dB CNBP): 47.1 (SD=17.46)

Results - Experiment II

Reinforcement Schedule & Novelty Effects

  • First Part: No effect of reinforcement schedule on response habituation or consistency among 2-year-olds (Group 4 vs Group 5).

  • Second Part: Novel reinforcement led to significant performance increase in Group 7 compared to Group 6 (t(22)=6.937, p<0.001).

Discussion

  • Discriminative Stimulus Findings: DS properties didn’t influence conditioning rate or response behavior, suggesting that complex signals commonly used can effectively assess auditory function.

  • Reinforcement Schedule Findings: Lack of impact of variety in reinforcement on 2-year-old children supports a conservative reinforcement strategy during evaluations. - Age Findings: 1-year-olds respond more than 2-year-olds, with significant importance on selecting reinforcement strategies for effective testing based on age differences.

Acknowledgments

  • Author: Based on the doctoral dissertation by Michael A. Primus at the University of Washington.

  • Study Location: Child Development and Mental Retardation Center, University of Washington.

References

  • Extensive referencing included, supporting research methodology and findings pertaining to operant conditioning, auditory assessment, and child development studies.