Variable Ratio Reinforcement
Continuous reinforcement can lead to satiation, making it less effective, while variable ratio schedules maintain high response rates even with less frequent rewards. This unpredictability is why gambling, particularly in slot machines, is so addictive; players are driven by the hope that the next attempt could yield a win, making it difficult to stop. The design of these systems cleverly exploits our behavioral tendencies, reinforcing the urge to keep playing.In this clip
From this podcast

The Science of Everything Podcast
Episode 29: Operant Conditioning
Related Questions
Can you explain scientifically why variable rewards are more addictive?
Why are variable dopamine rewards more addictive than consistent dopamine rewards, such as in gambling?
What is the difference between a random reward schedule in gambling and consistently rewarding ourselves for a long period of time when it comes to addiction?