The study looked at how people behave in multiple prisoner's dilemma games with or without an outside option. The researchers found that:

• People use a mix of random and patterned behavior when playing these games.
• Giving people the choice to play or not increases cooperation.
• When the outcome of both players choosing to defect is bad, people tend to cooperate to avoid losses.
• But when the outcome of both players defecting is good, people tend to stick to mutual defection.