His theories are based around the work of BF Skinner, who discovered you could control behavior by training subjects with simple stimulus and reward. He invented the "Skinner Box," a cage containing a small animal that, for instance, presses a lever to get food pellets. Now, I'm not saying this guy at Microsoft sees gamers as a bunch of rats in a Skinner box. I'm just saying that he illustrates his theory of game design using pictures of rats in a Skinner box. This sort of thing caused games researcher Nick Yee to once call Everquest a "Virtual Skinner Box."
First, set up the "pellets" so that they come fast at first, and then slower and slower as time goes on. This is why they make it very easy to earn rewards (or level up) in the beginning of an MMO, but then the time and effort between levels increases exponentially. Once the gamer has experienced the rush of leveling up early, the delayed gratification actually increases the pleasure of the later levels. That video game behavior expert at Microsoft found that gamers play more and more frantically as they approach a new level.Behaviourist game design techniques are becoming more prevalent in the age of online games, where the maker's revenue comes not from once-off purchases but from time (and money) spent in the course of playing the game; hence, game designers have to get their players hooked before the other guy comes along and milks them. And milking is perhaps an apt metaphor, given that one of the leading examples of this sort of game design is the Facebook game FarmVille, which, by all accounts is more of a socially conditioned obligation than a ludic activity:
Farmville is not a good game. While Caillois tells us that games offer a break from responsibility and routine, Farmville is defined by responsibility and routine. Users advance through the game by harvesting crops at scheduled intervals; if you plant a field of pumpkins at noon, for example, you must return to harvest at eight o’clock that evening or risk losing the crop. Each pumpkin costs thirty coins and occupies one square of your farm, so if you own a fourteen by fourteen farm a field of pumpkins costs nearly six thousand coins to plant. Planting requires the user to click on each square three times: once to harvest the previous crop, once to re-plow the square of land, and once to plant the new seeds. This means that a fourteen by fourteen plot of land—which is relatively small for Farmville—takes almost six hundred mouse-clicks to farm, and obligates you to return in a few hours to do it again. This doesn’t sound like much fun, Mr. Caillois. Why would anyone do this?
The secret to Farmville’s popularity is neither gameplay nor aesthetics. Farmville is popular because in entangles users in a web of social obligations. When users log into Facebook, they are reminded that their neighbors have sent them gifts, posted bonuses on their walls, and helped with each others’ farms. In turn, they are obligated to return the courtesies. As the French sociologist Marcel Mauss tells us, gifts are never free: they bind the giver and receiver in a loop of reciprocity. It is rude to refuse a gift, and ruder still to not return the kindness. We play Farmville, then, because we are trying to be good to one another. We play Farmville because we are polite, cultivated people.Here's more about FarmVille's use of the Cialdini reciprocity principle, as beloved of grifters. Meanwhile, other gaming companies are using other techniques to keep the marks coming back, like taking advantage of players' loss aversion ("your account is now flagged to have your characters below level 20 deleted as part of maintenance. Please re-activate your account now to ensure that your characters progress and names stay intact").
On a tangent, there is a blog titled The Psychology of Games; some of its content has to do with psychological manipulation techniques to control and monetise gamers, though it also covers examples of game theory (in the Prisoner's Dilemma sense) in games, psychoeconomics, the enjoyment of gaming as an activity, and, indeed, a wealth of psychological phenomena as illustrated through video gaming.