Play is important for the development of complex social, emotional, physical, and cognitive skills. Play provides young individuals with a safe space to practice new behaviors without grave repercussions. While most animals engage in play, only humans engage in rule-based games. Which kinds of games people play—competitive or cooperative—may depend on their cultural background. In a new study, published in PLoS ONE, researchers from Germany and Australia screened historical data to answer the question whether cultures play games that correspond to how cooperative they are.