ABA Fundamentals

Probability Relations within Response Sequences under Ratio Reinforcement.

Mechner (1958) · Journal of the experimental analysis of behavior 1958
★ The Verdict

Fixed-ratio schedules always give a pause after reward and a fast burst to the next one — plan for it.

✓ Read this if BCBAs who use token boards, sticker charts, or any response-count system.
✗ Skip if Clinicians who only run time-based or interval programs.

01Research in Context

01

What this study did

Mechner (1958) laid out the math of fixed-ratio schedules. The paper asked: what happens when every Nth response earns food?

It sketched the now-famous pattern: a pause after reward, then a fast run to the next payoff. No birds or data tables appear; the work is pure theory.

02

What they found

The model predicted two hallmarks we still teach today. First, post-reinforcement pauses grow with the ratio size. Second, once the bird starts, it finishes the burst at a high steady rate.

03

How this fits with other research

Mazur (1983) ran the experiment and confirmed the pause-plus-burst picture. The steady run speed stayed the same across FR, mixed, and random ratios; only the pause length changed.

Matthews et al. (1987) showed the same rules shape choice. Pigeons picked the sequence that started with the smaller ratio, even if it paid less often. The 1958 logic still held; the new twist was that the early ratio controlled preference.

Hamm et al. (1978) added a wrinkle. FR schedules locked pigeons into one response spot, while fixed-interval let them vary where they pecked. Same year, same lab, but the schedules acted differently on response form, not just rate.

04

Why it matters

When you set a token board or sticker chart, you are using FR mechanics. Expect a brief pause right after the payoff, then a quick stretch of work until the next token. If you see long pauses, shrink the ratio or add praise during the pause; the burst rate will likely stay high. This 1958 blueprint still guides everyday program tweaks.

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→ Action — try this Monday

Count the post-reinforcement pause in your token board; if it tops five seconds, drop the ratio by one and watch the burst return.

02At a glance

Intervention
not applicable
Design
theoretical
Finding
not reported

03Original abstract

Skinner's original description of the effects of fixed-ratio reinforcement schedules in terms of response-rate measures (14) has served as the point of de- parture for all such subsequent investigations. The two salient aspects of fixed- ratio performance that have thus far received the most attention are the high re- sponse rates toward the end of the inter-reinforcement period and the character- istic pause after the delivery of a reinforcement

Journal of the experimental analysis of behavior, 1958 · doi:10.1901/jeab.1958.1-109