ABA Exam Coach

B.9: Identify and distinguish among simple schedules of reinforcement.

Free practice questions for this part of the BCBA, with an explanation for every option.

A teacher praises a student for being in her seat the first time she is seated after an unpredictable interval that averages 5 minutes (sometimes 2 minutes, sometimes 8). Which schedule is in effect?
  1. A. Variable interval (VI) 5 min
    Correct. Reinforcement is given for the first response after a varying amount of time with a mean of 5 minutes.
  2. B. Variable time (VT) 5 min
    Incorrect. Time-based schedules deliver reinforcers regardless of responding. Here a response (being seated) is required.
  3. C. Variable ratio (VR) 5
    Incorrect. A VR schedule is based on the number of responses, not time.
  4. D. Fixed interval (FI) 5 min
    Incorrect. The interval changes from one reinforcer to the next, so it is not fixed.
A cumulative record shows a pause after each reinforcer, followed by a gradually accelerating rate of responding that peaks just before the next reinforcer. This "scallop" pattern is characteristic of which schedule?
  1. A. Fixed interval
    Correct. FI schedules typically produce a post-reinforcement pause and then responding that speeds up as the interval nears its end.
  2. B. Fixed ratio
    Incorrect. FR schedules produce a pause followed by an abrupt shift to a high, steady rate (break-and-run), not gradual acceleration.
  3. C. Variable ratio
    Incorrect. VR schedules produce high, steady rates with few pauses.
  4. D. Variable interval
    Incorrect. VI schedules produce low-to-moderate steady rates without scallops.
At a warehouse, an incentive plan pays packers a $5 bonus for every 20 boxes packed and labeled correctly. Which simple schedule of reinforcement describes this plan?
  1. A. Variable ratio 20 (VR 20)
    On a VR schedule, the number of responses required changes around an average. Here the requirement is always exactly 20 boxes.
  2. B. Fixed interval 20 (FI 20)
    Interval schedules depend on time passing before a response is reinforced. This bonus depends only on the number of boxes packed.
  3. C. Variable interval 20 (VI 20)
    A VI schedule is time-based and unpredictable. The bonus depends on a fixed count of responses.
  4. D. Fixed ratio 20 (FR 20)
    Correct. Reinforcement follows a fixed number of responses (every 20 correctly packed boxes). That is a fixed-ratio schedule.

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