What Is a Fixed-Ratio Schedule?

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In operant conditioning, a fixed-ratio schedule is a schedule of reinforcement where a response is reinforced only after a specified number of responses. Essentially, the subject provides a set number of responses, then the trainer offers a reward. One advantage of a fixed-ratio schedule is that it produces a high, steady rate of responding with only a brief pause after the delivery of the reinforcer.

Fixed-Ratio Schedule in Operant Conditioning

Operant conditioning involves strengthening or weakening behaviors via rewards and punishments. This type of associative learning changes behavior based upon that behavior's consequences.

If a behavior is followed by a desirable consequence, that behavior is more likely to occur again in the future. If, on the other hand, an action is followed by an undesirable consequence, the action becomes less likely to take place again in the future.

Behaviorist B.F. Skinner observed that the rate at which a behavior was reinforced, or the schedule of reinforcement, had an impact on the frequency and strength of the response.

The fixed-ratio (FR) schedule is just one of the schedules that Skinner identified. Other schedules of reinforcement are:

How the Fixed-Ratio Schedule Works

The fixed-ratio schedule of reinforcement can be understood by looking at the term itself. "Fixed" refers to the delivery of rewards on a consistent schedule. "Ratio" refers to the number of responses that are required in order to receive reinforcement.

For example, a fixed-ratio schedule might involve the delivery of a reward for every fifth response. After the subject responds to the stimulus five times, a reward is delivered.

So, imagine that you are training a lab rat to press a button in order to receive a food pellet. You decide to put the rat on a fixed-ratio 15 (FR-15) schedule. In order to receive the food pellet, the rat must engage in the operant response (pressing the button) 15 times before it will receive the food pellet.

The schedule is fixed, so the rat will consistently receive the pellet every 15 times it presses the lever. It doesn't matter how long it takes the rat to get to 15 presses.

Effectiveness of a Fixed-Ratio Schedule

What impact does this schedule have on response rates? The fixed-ratio schedule of reinforcement results in a high, steady response until the reinforcement is delivered. There is a brief response pause after reinforcement, but responding quickly resumes.

Typically, the FR schedule leads to very high rates of response that follow a burst-pause-burst pattern. Subjects will respond at a high rate until the reinforcement is delivered, at which point there will be a brief pause. However, responding will resume once again at a high rate.

This high rate of response is one of the advantages of a fixed-ratio schedule. One possible disadvantage is that subjects may quickly become exhausted from such a high response rate. Or, they may become satiated after several reinforcements have been given.

Fixed-ratio schedules are often used after a response has been learned, but you want to reinforce it. In the rat example, the rat has learned that pressing the bar earns a food pellet. To make sure the rat continues this behavior, you can reinforce it on a fixed ratio.

Examples of Fixed-Ratio Schedules

To better understand what a fixed-ratio schedule of reinforcement looks like, consider these examples.

• Production line work: Workers at a widget factory are paid for every 15 widgets they make. This results in a high production rate and workers tend to take few breaks. A fixed-ratio schedule can, however, lead to burnout and lower-quality work.
• Collecting tokens in a video game: In many video games, you have to collect so many tokens, objects, or points in order to receive some type of reward. This is an incentive to keep playing.
• Sales commissions: On a fixed-ratio schedule, a sales rep might earn a commission for every third sale that they make.
• Grades: A child is offered a reward after they earn five A’s on their homework assignments. After the fifth A on a homework assignment, the child gets to pick out a new toy.
• Piecework: Jobs require a certain amount of responses in order to receive compensation. For example, a worker receives a set dollar amount for every 100 envelopes they stuff or every 100 fliers they stick on windshields.
• Farm work: Farmworkers are paid a certain amount of dollars for every basket of fruit that they pick.

A Word From Verywell

A fixed-ratio schedule of reinforcement can be a useful approach to certain situations that use operant conditioning. When choosing a schedule, however, it is important to think about factors such as how frequently you want the subject to respond and how often you want to provide a reward.

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1. Strohacker K, Galarraga O, Williams DM. The impact of incentives on exercise behavior: a systematic review of randomized controlled trialsAnn Behav Med. 2014;48(1):92‐99. doi:10.1007/s12160-013-9577-4