[Bungie's head of user research takes another look at his decade-plus old article, which has become both influential and infamous for its suggestion that games can be better when developers take the psychology of players into account.]

A lone scientist labors late into the night in his lab, assembling his creation piece by piece, and then releases it to rampage across an unsuspecting world! Muwhahahaha!

No, not Frankenstein. Behavioral Game Design!

When I wrote that article a decade ago, I was a psychology graduate student and amateur game designer who had never worked in the games industry. Since then, the article has run amok, living an almost completely independent existence in the wilds of the internet.

It's been translated into multiple languages and assigned as homework. It's been cited by academics, pilloried by the Huffington Post, and even lampooned by my childhood favorite, Cracked magazine.

[Footnote: This actually makes me the second of Bungie's employees to be called out by Cracked. Their treatment of our security chief was much more complimentary.]

And as anniversaries tend to do, the 10 year anniversary of this article has spurred a lot of reflection on my part. The industry has changed almost beyond recognition since 2001, and I'd like to take the opportunity to ruminate publicly about where this topic has gone in the past decade.

Reinforcement learning has been acknowledged as a powerful force in game design.

The biggest change is that it's hard to find a game today that doesn't take its reward structure seriously. At the time of the article, it was a radical idea to say that games contained rewards and that the way those rewards were allotted could affect how people played. Now it's simply a given.

The clearest example of the acceptance of reinforcements in game design is the widespread use of achievements. Achievements are a really interesting case for study because there often isn't any tangible reward past the achievement itself. Some games, such as World of Warcraft, have used achievements to direct players towards alternate modes of play they might find more fun, such as exploration or PvP. In my eyes, helping players find more fun in the games they're already playing is one of the best uses of reinforcements.

The rise of social games on Facebook and elsewhere is another great example of how reinforcements have become a central topic in the games industry. Indeed, the early pioneers of this genre were basically reinforcement schedules with graphics. Their simplicity made it impossible for anyone analyzing them to misunderstand what made them so popular.

They had only three ingredients: well-structured rewards, strong viral communication channels, and high accessibility. Their runaway success has meant that no one will ever discount the power of those factors again. As competition among social games has grown, they've become much more sophisticated, but their contingencies still lie closer to the surface than in most genres.

The successful use of contingencies in games has also led to a reexamination of how they can be applied outside of games, on topics from fitness to encouraging safer driving. "Gamification" really has nothing to do with games and everything to do with contingencies. It's a little baffling that it took a fluffy entertainment field like games to make people take reward structures seriously on more serious topics, but it's nice that they are finally doing so.

Beyond behavioral psychology, the whole topic of psychology in games has gone mainstream. There are entire blogs devoted to studying how psychology and games interact, and some studios even keep full-time psychologists on staff.