Schedules of Reinforcement: What They Are and How They Work

Schedules of reinforcement play an important role in operant conditioning, a learning process in which new behaviors are acquired and modified through their association with consequences. Reinforcing a behavior increases the likelihood that it will occur again in the future while punishing a behavior decreases the likelihood that it will be repeated.

Why do schedules of reinforcement matter so much? When and how often we reinforce a behavior can dramatically impact the strength and rate of the response.

This article discusses what schedules of reinforcement are, the different schedules that can be used, and which one is best depending on the learning goals.

What Are Schedules of Reinforcement?

Schedules of reinforcement are rules stating which instances of behavior will be reinforced. In some cases, a behavior might be reinforced every time it occurs. Sometimes, a behavior might not be reinforced at all.

Either positive reinforcement or negative reinforcement may be used as a part of operant conditioning. In both cases, the goal of reinforcement is to strengthen a behavior so that it will likely occur again.

Reinforcement schedules occur in both naturally occurring learning situations and more structured training situations. In real-world settings, behaviors will probably not be reinforced every time they occur. In situations where you intentionally try to strengthen a specific action (such as in school, sports, or animal training), you would follow a specific reinforcement schedule.

Some schedules are better suited to certain types of training situations. In some cases, training might call for one schedule and then switch to another once the desired behavior has been taught. The two foundational forms of reinforcement schedules are referred to as continuous reinforcement and partial reinforcement.

Continuous Schedules of Reinforcement

In continuous reinforcement, the desired behavior is reinforced every single time it occurs. This schedule is best used during the initial stages of learning to create a strong association between the behavior and response.

Imagine, for example, that you are trying to teach a dog to shake your hand. During the initial stages of learning, you would stick to a continuous reinforcement schedule to introduce and establish the behavior. This might involve grabbing the dog's paw, shaking it, saying "shake," and then offering a reward each and every time you perform these steps. Eventually, the dog will start to perform the action on its own.

Continuous reinforcement schedules are most effective when teaching a new behavior. These schedules denote a pattern in which every narrowly defined response is followed by a narrowly defined consequence.

Partial Schedules of Reinforcement

Once the response is firmly established, a continuous reinforcement schedule is usually switched to a partial reinforcement schedule. In partial (or intermittent) reinforcement, the response is reinforced only part of the time. Learned behaviors are acquired more slowly with partial reinforcement, but the response is more resistant to extinction.

Think of the earlier example in which you were training a dog to shake. While you initially used continuous reinforcement, reinforcing the behavior every time, long after the dog has learned the trick, is simply unrealistic. In time, you would switch to a partial schedule to provide additional reinforcement once the behavior has been established or after considerable time has passed.

There are four schedules of partial reinforcement. Two are ratio schedules, which are schedules based on how many responses have occurred. The other two are interval schedules or schedules based on how much time has elapsed.

These four schedules of reinforcement are sometimes referred to as FR, VR, FI, and VI—which stands for fixed-ratio, variable-ratio, fixed-interval, and variable-interval.

Fixed-Ratio Schedules

Fixed-ratio schedules reinforce a response only after a specified number of responses. This schedule produces a high, steady rate of response with only a brief pause after the reinforcer is delivered.

An example of a fixed-ratio schedule would be delivering a food pellet to a rat after it presses a bar five times.

Variable-Ratio Schedules

Variable-ratio schedules occur when a response is reinforced after an unpredictable number of responses. This schedule creates a high steady rate of responding.

For example, in a lab setting, this might involve delivering food pellets to a rat after one bar press, again after four bar presses, and then again after two bar presses. Gambling and lottery games are good examples of a reward based on a variable ratio schedule.

Fixed-Interval Schedules

Fixed-interval schedules reward a first response is rewarded only after a specified amount of time has elapsed. This schedule causes high responses near the end of the interval but slower responses immediately after the reinforcer is delivered.

An example of this in a lab setting would be reinforcing a rat with a lab pellet for the first bar press after a 30-second interval has elapsed.

Variable-Interval Schedules

Variable-interval schedules occur when a response is rewarded after an unpredictable amount of time has passed. This schedule produces a slow, steady rate of response.

An example of this would be delivering a food pellet to a rat after the first bar press following a 30-second interval, a second pellet for the first response following a 90-second interval, and a third pellet for the first response following a 60-second interval.