I am an Angry Birds addict. It's been eight hours, 15 minutes, and 34 seconds since my last level. That was at 3:45 a.m. and the only reason I've lasted this long is that I ran out the battery on my phone and left it in my car.

Small comfort knowing that half the world shares this obsession, including David Cameron and Salman Rushdie.

We are all pathetic.

In November, Rovio Entertainment Ltd., the Finnish company that invented the infuriating, irresistible, fiendishly Skinnerian digital game, announced its 500 millionth download.

As of Dec. 11, when the game celebrated its second birthday, it had drained the world of 200,000 years of productive time.

Addicts around the globe squander 300 million minutes of playing time daily, Rovio reports.

Angry Birds is the No. 1 paid app on iTunes in 68 countries and the best-selling paid app ever. More than 266 billion levels of Angry Birds have been played. More than 400 billion birds slingshot across the virtual universe. More than three trillion pigs summarily executed. And more than 44 billion behavior-reinforcing stars rewarded.

To mark the game's conquest, Rovio's CEO, Mikael Hed, issued a self-congratulatory statement:

"We're extremely delighted to see such an incredible amount of people enjoying our games. We remain committed to creating more fun experiences."

We're doomed.

This week, my daughter, a counselor in a methadone clinic, got a call from one of her colleagues.

"I need your help."

"I'm finishing some paperwork," my daughter said. "I'll be right there."

"No!" said her colleague. "I need you right now!"

Worried about what was so urgent, she rushed down the hallway to find her coworker holding a smartphone.

"I can't get off this level. Help!"

It was a promising young journalist who turned me on to the birds, saying innocently, "You're going to love this."

For months, the app lay dormant (like an unlaunched cannonball), until I found myself on a Megabus to Boston and thought, well, here's a way to pass the time. Six hours later in South Station, I was pinned to my seat, muttering, "One more level and I'll get off."

Before the birds bit me, the only computer game I ever played was my kids' educational Where in the World Is Carmen Sandiego?

Now I lie in bed beside my husband, who is reading the New Yorker, and I guiltily rationalize that Angry Birds has redeeming value. It has a yogic, Zen-like effect, emptying the mind of distracting thoughts. It requires an understanding of physics. It improves index finger-eye coordination.

Studies show there is some small truth to these theories, but those researchers are probably slingshotting away so many hours themselves that they need to justify their own A.B. habit.

Junkies play it at red lights, walking down hospital corridors, and during lulls in conversation at dinner parties.

Searching for an explanation, I read the April issue of Wired magazine in which a psychology professor compared the birds to gambling.

"When we fail to win, we create a reason in our mind why we didn't," he says. "The losses effectively become near-wins and feel 'cognitively frustrating.' And the only way you can get rid of that frustration is to go back to the start and play again."

Seeking deeper analysis, I found Charles L. Mauro's blog post, "Why Angry Birds is so successful and popular: a cognitive teardown of the user experience."

Mauro, a computer engineering consultant, broke it down. The graphics. Response time. Short-term memory management.

I'm sure he's dead on. But I realized that I knew the answer all along. This is primal.

Anyone who has taken Psych 101 or trained a puppy knows the trick. Intermittent rewards. You keep trying because a little bit more now than then, when you topple the tower, explode the TNT, boomerang the bridge, your brain shivers with success.

Last week, I tried to quit. I had been sticking with the free app, the way college kids persuade themselves they're not potheads because they only smoke their friends' weed. My updated version featured advertisements in the upper right corner of the screen, obscuring the targets.

The ads have made Birders angry. Rovio has been catching hell from cheapskates like me who don't spring for the 99-cent version.

Me? I took it as a sign and deleted the app.

Then my daughter came over for dinner and asked me to help her. She was stuck on a level. I nailed it.

Before we cleared the dishes, I had relapsed. Sprung for the 99-cent version.