Even if you don't play Candy Crush Saga, you can't have missed the omnipresent news proclaiming it the game of the summer. It's the new Angry Birds. It has--naturally--inspired jewel-toned legwear and edibles

It's the top app in the world by number of users--of which it has 44 million regular ones, according to AppData. Daily, 6.6 million people play it, and, thanks to sophisticated in-game purchasing of more attempts at levels and other bonuses, that amounts to $632,867 in daily revenue for the company, according to Think Gaming

All that lucrative popularity is fueled not by some slick design, nor by some remarkable premise supported by masterful storytelling. Both, in the case of Candy Crush, actually leave much to be desired. The New York Times hypothesized that some of the game's appeal lies in its cross-platform synchronization and its user-testing of features and levels, which King, the London-based company behind the game, updates and rolls out to users with a frequency that would make Rovio's palms moist.

Part of the game's success stems from its continuity across platforms, [company representative Tommy] Palm said, a first for such a popular mobile game. That means players who start playing on Facebook and switch to their iPhones or iPads won’t lose their place or have to start over, he said. That’s different from earlier multi-platform games like Angry Birds. "If you lose your game, you still have your place saved," he said. "This is especially important for a game with such a long life span."

In addition, the game is designed to constantly evolve and be updated, he said, rather than add sequels or extensions like other popular game titles. Candy Crush Saga currently has 385 levels. Every other week King adds new levels or features.

Maybe it's just that I have a sister who's a behavioral psychologist and I've heard a lot about reinforcement schedules and the like (including the fascinating fact that most animals like to take a little risk for a big reward, illuminated by the fact that she taught several pigeons to gamble), but I think there's something beautifully motivating about Candy Crush that might be the real reason it's so damn popular.

When you run out of moves and you're staring at a maddeningly childish looking rainbow screen with a dancing doll or a genie on it, it's a feeling akin to being in an argument with a teenager--that "I probably shouldn't be wasting my time here but I should…should!...easily be able to win this." In that way, it feels like the losing, not the winning--and the random-ish nature of when winning happens--that makes it addictive.

The way my sister would explain it is that almost all gambling games use random or variable schedules of reinforcement, which, to highly simplify things, means that rewards come at random or differing intervals and have random or differing payoffs. Behaviors (in this case, swiping candies on the game screen or even your behavior of looking feverishly around the board) are reinforced by these random rewards, making them more "resistant to extinction." Meaning: you're likely to get hooked. It's perhaps easiest to think about this in the inverse: Wouldn't it be boring if every time you pulled the lever on a slot machine you got the same exact coin back? 

Yahoo Finance echoed this theory of some sort of perfect storm of behaviorist-style reinforcement being the root of so many people getting hooked--and spending money--on the game. 

But what about this makes Candy Crush impossible to quit? First, much like a Las Vegas slot machine, the game features unpredictable rewards. For instance, candies with special powers pop up or a single move leads to a cascade of other explosions across the whole grid, accompanied by silly sounds and cartoons. Psychologists call the tactic the partial reinforcement effect. "People keep responding in the absence of reinforcement hoping that another reward is just around the corner," says Mark Griffiths, director of the International Gaming Research Unit at the psychology department of Nottingham Trent University.

My sister says there's not only the random or variable schedules to blame when a game, project, or challenge gets you hooked. Here's how she explained it casually to me in an email.

Many games similar to Candy Crush take advantage of our desire to avoid losing, rather than winning points or levels, per se. This effect is more a product of negative reinforcement, in which our behavior persists because we don't want to face the aversive prospect of beginning the game again or paying money to continue. Many of us can likely relate when thinking about our own academically motivated behavior. When getting an exam back, are you excited that you just earned an 85 percent or--what's more likely--are you a bit disgruntled that you actually lost 15 points in the class? Rather than thinking of these as points to earn or games to win, we tend to think that we have them in our hands already: They are ours to lose. Unless, of course, we behave otherwise--and that is the real challenge.

The problem here is that the feeling of inadequacy in losing simply gets old. And the Yahoo piece notes that the enjoyment players get from both variable reinforcement and primal pattern recognition (here's a video explaining this concept) are addictive, but not engaging for the long-term. It says that's the reason Candy Crush could fade in popularity--and, thus, massive profitability--soon. 

Ultimately, pattern-matching games like Candy Crush fail to provide most people with a deep sense of engagement, and the brain eventually tires of constantly looking for patterns, [user-interface design expert Charles] Mauro indicates. Candy Crush may remain popular for a while longer, but that will “level off in a few months or so and then drop like a stone,” he expects. 

And if Candy Crush drops, that will leave King gaming, the 10-year-old company that created this phenomenon, scrambling for the next hit--or risk damaging its IPO prospects. In the era of Zynga's meteoric rise and fall, it's possible to wonder whether a major gaming house can ever sustain a bout of massive popularity. For now, at least, one thing's clear: It's good to be King.