2. Variable Ratio Schedule

• A high steady rate until reinforced
• No (or only a very small) pos-treinforcement pause.
• The value of a variable rate schedule can be increased a greater rate than a fixed rate schedule without producing ratio strain, and
• A high RTE and the values of variable ratio that can maintain responding are somewhat higher than those of a fixed ratio.

Examples in natural environments:

• Slot machines. Slot machines are programmed on VR schedule. The gambler has no way of predicting how many times he must put a coin in the slot and pull the lever to hit a payoff but the more times a coin is inserted the greater the chance of a payout. People who play slot machines are often reluctant to leave them, especially when they have had a large number of unreinforced responses. They are concerned that someone else will win the moment they leave.
• Playing golf. It only takes a few good shots to encourage the player to keep playing or play again. The player is uncertain how good each shot will be, but the more often they play, the more likely they are to get a good shot.
• Door to door salesmen. It is uncertain how many houses they will have to visit to make a sale, but the more houses they try, the more likely that they will succeed.

Examples in video games

• Collecting tokens. Some games require the player to collect tokens to achieve a life point or reward but vary the number of tokens required.
• Achieving a new level in an RPG. Some RPG's give no clear indication of how much experience is required to achieve the next level. The puts the player on a variable ratio schedule.
• Obtaining frags in an FPS. Many of your shots will fail and it is not certain what the outcome of any particular shot will be. However, the more targets you shoot at, the more likely you are to get a frag.
• Crafting in an RPG. It may take multiple attempts to succeed, or to gain a new level, but the more you try, the more likely your behavior is to be reinforced.