A truly social game involves players exchanging emotions, not just helping each other boost stats, according to thatgamecompany's co-founder Jenova Chen.

Speaking at the Games for Change Festival in New York this week, Chen said he takes issue with many games that market themselves as being social because he doesn't believe they encourage social behavior at all.

"Social means emotional exchange, not number exchange," he said, referring to examples like Zynga's FarmVille to illustrate how most people's idea of being social is helping another player by giving them resources or stat boosts, or World of Warcraft and Call of Duty, where multiplayer matches tend to focus on killing things.

"I wanted to see if I could create something that is emotional between people..."

"I wanted to see if I could create something that is emotional between people," he said, speaking of the development of thatgamecompany's critically-acclaimed Journey. "Existing games are about killing each other or killing something together. The idea of social emotion means people need to share feelings. At that moment, the players are in sync. The problem [with many games] is there's no chance to share emotion. Most of them are busy, [there are] explosions everywhere. So we got rid of all the background noise and we had to get rid of the guns."

To foster the sharing of emotions, thatgamecompany reduced the number of players on screen and placed them in a deserted environment where they rarely came across another player. The hope was "when you see a person, you don't think ‘I am going to shoot his head.'"

The developers also made the player's character small, because "when you make people feel big, they feel like gods. When you put two gods together, they fight."

"In Journey, we wanted you to care about each other," he said. "We removed [usernames], didn't allow friend invites;you're two people, you travel together, if you don't like each other you can walk away."

Chen said the development team went through 12 different prototypes before it settled on the final form of Journey, and that 75 percent of the game's development time was spent on research and development to find ways to make players emotionally connect with each other. According to Chen, in earlier prototypes, players gave each other grief when they encountered each other in the game, which wasn't the kind of connection the developers wanted to foster. Speaking to a behavioral psychologist, he learned that when players enter virtual worlds, they "behave like babies."

"Babies look for maximum feedback," he said. "And there's so much feedback in [virtually] killing someone. So the way we had to work against that was by controlling the kind of feedback was provided. We minimized the feedback for things we didn't want players to do, and maximized feedback for the behaviors we wanted."

So they minimized the feedback players received when they tried to hinder another player, and rewarded players with visually and aurally exciting feedback when they helped another player. The result was players were much more excited when they encountered each other in the game and, instead of trying to hurt each other, they formed connections.

Chen told the audience at Games for Change that he hopes to see more emotionally accessible games, and that future games evoke a broader spectrum of emotions within us like films do. "The only way we can do it is by putting our heart into it," he said.