Yvette with animals in a scene from Zynga's CastleVille, the latest… (Zynga )
All it took was a single click on a friend's Facebook post. With it, Lana Sumpter — a Tennessee university professor — began a three-year habit that has consumed many late night hours and cost many thousands of dollars.
The game was Mafia Wars, created in 2008 by up-and-coming developer Zynga Inc., now the largest player in the $1 billion-a-year social games genre. Its CityVille and FarmVille draw more than 148 million players every month to their Facebook sites. Like Sumpter, many of them come day after day, using credit cards or gift cards to "to "play, pay and share" the game, said Nicole Lazzaro, founder of XEODesign and a consultant on the role of emotion in games.
Some time in the next two weeks Zynga will launch CastleVille, a "Princess Bride" meets "Tangled" game in which players build castles, encounter oddball fairy tale characters, encourage them to become loyal subjects, then try to conquer the Gloom, a mysterious force that has spread sadness throughout the kingdom.
"Come to a land where happiness rules," beckons one of the game's advertisements.
Online is where social gaming rules. Analysts of the genre say these games appeal at an almost addictive level to basic human instincts for companionship, generosity and competitiveness. On Facebook, the online gaming community includes 750 million active users.
CastleVille is Zynga's most ambitious game to date, and represents the company's most sophisticated attempt to hook in players, get them to recruit their Facebook friends and add to the community of online Zynga players.
Appealing innovations include "gifting," which enables players to present their friends with a tree to decorate their farm or a cow that makes milk, for example, and "visiting," which rewards players with experience points and in-game currency for checking out their friends' kingdoms and helping out by harvesting crops or stomping out "beasties."
Gifting and visiting don't cost players any cash, but they do accomplish key Zynga goals, according to analysts.
The virtual gifts create a sense of abundance, Lazzaro said. "People feel they can be generous, encouraging them to give even more," creating a never-ending cycle of back-and-forth gift-giving that invites recipients to come back to the game.
Visiting draws on several basic emotions, including curiosity to know what other players are building and sometimes envy of what they build.
"It's just human nature to be curious about what my friends value and care about," said Bill Jackson, the game's creative director. And, suggested Lazarro, "If I visit your farm and I see that you have something that I don't, it can inspire me to try to get it too."
CastleVille and similar games also entice players by enabling them to customize their online worlds.
Players can select from hundreds of hairstyles, outfits, costumes and body types to create their avatar, the character that personifies the player in the game.
In some Zynga games, these customizations cost money. In CityVille, adding a "Pumpkin Palace" costs $6.25. On CastleVille, adding a unicorn topiary costs fifteen cents.
It's a trick many social games have used to get people to keep coming back, said AJ Glasser, lead writer for Inside Social Games, an industry newsletter.
"Whenever players get to create and control a character, they tend to invest a certain amount of themselves into the game," Glasser said. "It creates an emotional connection between the player and the game."
The social component kicks in when players share their creations, said Brian Reynolds, Zynga's chief game designer. "The big shift with social games is the fact that you are now playing with your actual friends from real life," he said. "That's where the magic comes from. Our brains are wired to socialize."
And socialization is one of the components of happiness, said Jason Brown, Zynga vice president of player insight.
"Our games tap into some fundamental drivers of human happiness," Brown said. "They give people moments of pleasure (and) a sense of accomplishment. And they help people connect with each other. One player proposed marriage to another by spelling out 'will you marry me' with the crops on his farm. Fortunately, she said yes."
Social games also rely on scarcity to get people to come back, sometimes several times a day. Otherwise known as "The Cliffhanger," this method deliberately frustrates the player by preventing them from going further in the game, often while they're in the middle of a task.
Most social games dole out a limited amount of energy that players use each time they take an action. In CastleVille, players may be fortifying their castles or fighting a battle when they run out of "energy." It may take four to six hours for their "energy" to be replenished.