Starting in the 1930s, a psychologist named B.F. Skinner did a series of experiments involving rats, pigeons, and something called a Skinner Box. The experiments involved conditioning the animals to activate a lever and rewarding them for the behaviour with food based on a variety of different reward schedules.

It turns out that a Variable Ratio schedule, where you give out rewards after random number of actions is the best way to get an animal to hit a lever over and over again. Unlike more predictable schedules, which are associated with a lull in activity after the reward is given out, Variable Ratios mean that any lever press could be the one that dispenses food. In the delightful language of psychology “Variable schedules produce higher rates and greater resistance to extinction than most fixed schedules.” Extinction is when you stop doing something because it’s stopped rewarding you.

I first came across the Variable Ratio reward schedule in an article on Gamasutra about using behavioural psychology to make games more fun. If you stop and think for a moment, you’ll recognize the schedule in the loot drops of Diablo and just about every MMO and RPG in existence. You’ll see it in the random power-ups dropped by enemies in FPSs and SHMUPs. And you’ll see it in slot machines, Craps tables and just about every other form of gambling.

We have a funny relationship with addictiveness in this industry. When reviewers talk about a game being addictive, it’s high praise. When publishers talk about it it’s a laudable business goal or a selling point. As part of the Civilization IV marketing campaign they released a series of ads and a website for CivAnon, an Alcoholics Anonymous for Civ gamers.

Perhaps conditioned by years of defending ourselves from the charge that games are corrupting the youth, when it comes to the idea that games might be addictive for real we tend to circle the wagons.

At some point, the industry is going to have to take serious stock of the charge the claim that games are addictive. More specifically, that we have a moral obligation that conflicts with our financial obligations to decide how addictive we want our games to be.

Consider this quotation from the Gamasutra article:

The distinct pause shown under a fixed ratio schedule can be a real issue for game designers. Having a period of time where there is little incentive to play the game can lead to the player walking away.

The business side screams “OH GOD NO, we can’t let them walk away from the game! They might stop paying!” The ethical side should be asking “Ok, I want them to like this game and keep playing it, but I also want them to have a rest of their life. Where’s the balance?” Jonathan Blow asked this question eloquently at MIGS 2007. Raph Koster asked it again just last week.

If we can agree that the tobacco industry should be held culpable for deciding how much nicotine to put in its cigarettes and we can believe that there is such a thing as problem gambling, then we have to accept that it’s possible to make games that are too addictive. We have to accept the possibility that we may already have.