Glossary / Lexicon

Deutsch: Variabler Intervall / Español: Intervalo Variable / Português: Intervalo Variável / Français: Intervalle Variable / Italiano: Intervallo Variabile

Variable-Interval refers to a type of reinforcement schedule in which rewards or consequences are provided after varying amounts of time have passed, based on an unpredictable pattern. In psychology, particularly in behavioural psychology and operant conditioning, this schedule is used to reinforce behaviours intermittently, keeping the subject engaged in the behaviour even though the exact timing of the next reward is unknown.

Description

In psychology, variable-interval (VI) schedules are a key concept in operant conditioning, a learning process first described by B.F. Skinner. Under a variable-interval schedule, the reinforcement (or reward) is delivered after varying intervals of time, meaning the subject cannot predict exactly when the reward will come. This creates a consistent level of behaviour over time, as individuals are motivated to continue performing the desired action in the hope of receiving the reinforcement.

Unlike fixed-interval schedules, where reinforcement occurs after a set, predictable amount of time (e.g., every 5 minutes), variable-interval schedules are unpredictable. For example, reinforcement may be given after 3 minutes, then after 7 minutes, then after 2 minutes, and so on, with the timing of the next reward always changing.

This unpredictability typically leads to steady and persistent behaviour, as the subject cannot anticipate when the reward will arrive, but knows that continuing the behaviour will eventually lead to a positive outcome. In practice, the behaviour tends to occur at a relatively slow but stable rate, as subjects engage in the behaviour at regular intervals to maximise their chances of receiving reinforcement.

In real life, variable-interval schedules are common in everyday situations. A classic example is checking for an email or social media notification. The reinforcement (a new message or notification) appears at unpredictable intervals, encouraging individuals to check their devices frequently, as they are rewarded intermittently.

Application Areas

Variable-interval schedules are used in a variety of settings, both in psychology and in everyday life:

• Behavioural psychology: Used in experiments to understand how different schedules of reinforcement affect learning and behaviour. VI schedules are often used to promote stable, ongoing behaviours without burnout.
• Education: Teachers might use variable-interval reinforcement to encourage students to consistently engage in positive behaviours, like staying on task or completing assignments.
• Workplace: Employers can use VI schedules to motivate employees by providing bonuses or feedback at unpredictable intervals, encouraging ongoing effort and performance.
• Animal training: Trainers might use variable-interval reinforcement to maintain certain animal behaviours, such as having a dog sit patiently or perform a trick repeatedly.

Well-Known Examples

1. Checking emails or social media: People tend to check their inbox or notifications regularly throughout the day because new messages appear at unpredictable times, making the behaviour resistant to extinction.
2. Pop quizzes in education: When students know that quizzes are given at random intervals throughout the term, they are more likely to study consistently to be prepared, as the next quiz could happen at any time.
3. Fishing: Fishing operates on a variable-interval schedule, as the fisherman never knows when a fish will bite. The unpredictability of catching a fish encourages persistent behaviour.

Risks and Challenges

While variable-interval schedules are effective at maintaining consistent behaviour, they also present challenges:

• Slow learning: Since reinforcement is unpredictable, it may take longer for a behaviour to be learned or strengthened compared to other reinforcement schedules.
• Frustration: The unpredictability of reinforcement can sometimes cause frustration or disengagement if the subject feels that rewards are too infrequent.
• Overchecking or overuse: In certain contexts, like checking smartphones or social media, variable-interval schedules can lead to compulsive behaviours, as users keep checking for potential rewards (notifications) even when it may not be productive.

Similar Terms

• Fixed-interval schedule: Reinforcement is given after a set, predictable amount of time, leading to behaviour that increases as the time for reinforcement approaches.
• Variable-ratio schedule: Reinforcement is provided after a variable number of responses, rather than after a period of time. This is often associated with high rates of behaviour, like gambling.
• Fixed-ratio schedule: Reinforcement is given after a fixed number of responses, leading to high rates of behaviour, with a pause after each reinforcement.
• Operant conditioning: The broader psychological concept in which behaviour is shaped by consequences, either reinforcing or punishing, as described by B.F. Skinner.

Summary

Variable-interval schedules in psychology refer to reinforcement that is given after unpredictable amounts of time, encouraging steady and persistent behaviour. Commonly studied in operant conditioning, this type of schedule helps maintain behaviours over time, making it applicable in areas such as education, animal training, and even everyday activities like checking emails. While it promotes consistent action, it may lead to slower learning and frustration due to the unpredictable nature of rewards.

--