Chaining Types and Selection in Behavioral Training

Distinction Between Shaping and Chaining

  • Shaping

    • Reinforces successive approximations of a single response class that share a common dimension (e.g.
    • Floating → legal breast-stroke arm-pull).
    • Focus: quality/​form of one behavior.

  • Chaining

    • Builds a sequence of different behaviors that must occur in a specific order to access reinforcement.
    • Example: Full breast-stroke (arm-pull → breath → kick → glide).
    • Incorrect timing/​order ↓ speed ⇒ demonstrates why correct chaining matters.

Overview of Chaining Procedures

  • Three main variants:
    1. Forward chaining
    2. Backward chaining
    3. Total-task presentation (TTP)
  • Shared goal: move from contrived, dense reinforcement to maintenance by natural contingencies (e.g. “feeling of speed” in water, “clean mouth” after brushing).

Forward Chaining

  • Procedure
    • Teach Step 1 to mastery → add Step 2 → continue sequentially until full chain performed.
    • Target step = current step being trained; receives extra prompts & reinforcement initially.
    • Fade prompts & thin reinforcement at each mastered step.
  • Why/When to Use
    • Logical or temporal order matters (e.g. breast-stroke, assembling furniture).
    • Learners who tolerate brief reinforcement delays.
  • Example Details
    • Tooth-brushing:
    • Step 1: pick up brush (R+ = therapist praise)
    • Step 2: apply paste (R+ = small token)
    • … eventually natural R+ = \text{"clean" taste} & cavity prevention.

Total-Task Presentation (TTP)

  • Procedure
    • Train all steps on every trial.
    • Prompt through errors immediately; require completion of whole sequence each attempt.
  • Typical Contexts
    • Job training, software tutorials, daily-living skills for individuals who can sustain attention.
  • Pros / Cons
    • + Mirrors real-world instruction, efficient if learner already knows many steps.
    • − Can overwhelm young children or learners with limited tolerance → frustration.

Backward Chaining

  • Procedure
    • Instructor completes every step except the last; learner performs final response and contacts terminal reinforcer immediately.
    • Once last step mastered, teach next-to-last, etc., moving “backward” up the chain.
  • Benefits
    • Immediate access to natural terminal reinforcer on every trial (e.g. tied shoes, finished obstacle course).
    • Reduces aversiveness for demand-sensitive learners.
  • Illustrative Examples
    • Shoe-tying: learner only pulls final knot at first; enjoys “done” status → gradually takes over loops, crossing, etc.
    • Rat obstacle course (video): rat first completes final barrier for treat, then second-to-last, etc.

Selecting the Right Chaining Strategy

  • Research base: Little definitive evidence that one procedure universally outperforms another.
  • Decision variables
    • Learner’s preferences & cognitive/​motor abilities.
    • Attention span & demand tolerance.
    • Existing repertoire (already knows many steps → TTP; knows none → forward/​backward).
    • History with chaining (prior success/​failure data).
    • Contextual fit (e.g. adults in workplace unlikely to accept backward chaining).
  • Data-Driven Approach
    • Collect trial-by-trial data (latency, accuracy, prompt level).
    • If chosen method stalls → switch & compare.
    • Remember: \text{ABA} is an experimental science; use single-case designs when feasible.

Practical / Ethical Considerations

  • Fade from contrived to natural reinforcement to avoid dependency.
  • Maintain social validity: interventions should seem reasonable to stakeholders (e.g. employees, parents, clients).
  • Avoid learner frustration: balance task difficulty & reinforcement density.
  • Encourage generalization & maintenance by ensuring naturally occurring R+ is salient.

Additional Resources & Real-World Connections

  • Swimming metaphor captures difference between refining one movement (shaping) vs. combining many (chaining).
  • Rat Lab opportunity
    • Undergraduate course allows hands-on chaining research with live rats.
    • Demonstrates cross-species applicability of ABA principles.
  • Video suggestion: Student-produced clip shows backward chaining in obstacle course for clearer visualization.
    • Observe: prompt hierarchy, immediate R+, systematic step addition.

Key Takeaways for Exam Prep

  • Define & distinguish shaping vs. chaining.
  • List & describe forward, backward, TTP procedures.
  • State advantages/​limitations & appropriate learner profiles for each.
  • Explain why fading contrived reinforcement toward natural contingencies is critical.
  • Use provided examples (breast-stroke, shoe-tying, software training) to illustrate concept application.