Research Cluster

Concurrent VI Schedules and Choice

This cluster shows how pigeons pick between two buttons that give food at random times. It tells us that slower overall rewards make animals less picky about which button pays more. It also shows that how hard you have to press, how long you must wait after switching, and how rewards add up across the session all change the way animals switch back and forth. BCBAs can use these rules to set up choice tasks for kids that keep them engaged and help them learn to prefer better options.

144articles
1961–2025year range
5key findings
Research Synthesis

What the research says

Choice is not random. When a person or animal chooses between two activities, they follow rules — and those rules are predictable. The research in this cluster explores what happens when two sources of reinforcement are available at the same time. The main principle is called the matching law: organisms allocate their behavior in proportion to the reinforcement they receive. They do not maximize — they match.

What does this mean in practice? A learner who gets more reinforcement for one behavior will do that behavior more. If two behaviors get equal reinforcement, they will do each equally. Studies show that even small differences in reinforcement rate create a preference. The richer option wins, and the effect grows as the difference between options gets larger.

Key Findings

What 144 articles tell us

  1. Behavior is allocated in proportion to relative reinforcement rate — the richest option gets the most responding.
  2. Small differences in reinforcement rate create detectable preferences; bigger differences produce stronger preferences.
  3. Requiring a delay before switching between options reduces switching and strengthens commitment to the current choice.
  4. When overall reinforcement is low, learners become less discriminating between options — this is called undermatching.
  5. Variable-ratio token exchange may be preferred by students even when it does not change their work rate.
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Deeper Dive

What else the research shows

Several studies explore what changes this pattern. If it is harder to switch between options — for example, if there is a delay after switching called a changeover delay — organisms switch less and become more committed to the option they are on. If overall reinforcement drops, they become less discriminating — the ratio of preferences weakens when everything pays less. This is called undermatching.

Research also shows that token economies follow schedule logic. Kids may prefer variable-ratio token exchange — where the number of tokens needed to cash in varies — even if it does not increase their work rate. This has practical implications for how you design token boards. And historical reinforcement matters: what the learner has experienced in past sessions influences how they respond to new schedules, sometimes for many sessions.

Monday Morning Actions

How to apply these findings

Use matching law thinking when a client is choosing problem behavior over appropriate behavior. The problem behavior is winning because it is delivering more, faster, or better reinforcement. You do not need to make the appropriate behavior perfect — you just need to tip the ratio. Research shows that even a modest increase in reinforcement for the desired behavior, or a modest thinning of accidental reinforcement for the problem behavior, changes the choice.
When designing a token economy, consider giving students a choice in how they exchange tokens. Research shows that some students prefer variable-ratio exchange schedules — where cashing in requires different numbers of tokens each time — even when the average rate is the same as fixed exchange. Letting students choose their preferred exchange schedule increases buy-in without requiring you to change the underlying work requirements.
Watch for undermatching when overall reinforcement in your session is low. If you are running lean schedules across the board, learners may lose sensitivity to the differences between your options — they may respond randomly rather than selecting the better choice. This is not a motivation problem. It is a schedule problem. Enrich the overall reinforcement rate in the session and preference discrimination should return.

Frequently Asked Questions

Common questions from BCBAs and RBTs

The problem behavior is delivering more reinforcement. The matching law predicts that people allocate behavior in proportion to relative reinforcement rates. To compete, you need to increase the reinforcement for the appropriate behavior, reduce accidental reinforcement for the problem behavior, or both. Even a moderate shift in the ratio changes the choice.

The matching law is the finding that organisms allocate their behavior in proportion to the reinforcement they receive from each option. A BCBA who understands this knows that the goal is not to eliminate problem behavior — it is to make the reinforcement ratio favor appropriate behavior. It applies directly to how you set up token economies, FCT programs, and any situation with competing response options.

A changeover delay is a wait time after switching from one option to another before reinforcement becomes available. Research shows that longer changeover delays reduce switching and create stronger commitment to the current option. This can stabilize behavior on a preferred alternative but can also make it harder to redirect to a different activity.

Yes. Research shows that token exchange schedules follow schedule logic — kids may prefer variable-ratio exchange where the number of tokens needed to cash in varies, even if it does not change their work rate. Testing student preferences for different exchange schedules can improve motivation without changing the underlying work requirement.

Undermatching is when a learner shows weaker preference than the reinforcement ratio would predict. Research shows it is most common when overall reinforcement rates are low. When everything pays little, the learner stops discriminating between options. If you see near-random responding across choices, check whether your overall reinforcement density in the session is too lean.