They assigned some students to play a video game that the researchers deemed prosocial-either Super Mario Sunshine (pictured above), in which Mario must clean up environmental pollution, or Chibi Robo, where players assume the role of a robot who helps a family manage their house...

...After playing the game, the students were paired with another person and told to make their partner complete 11 puzzles from a selection of 30 - 10 of which were hard, 10 easy, and 10 in between. They were informed that if their partner was to solve 10 of the puzzles correctly, then the partner would receive a $10 gift certificate. The researchers deemed a person's behavior as "helpful" if the participant gave his or her partner an easy puzzle, "hurtful" if the puzzle was hard, and "neutral" for medium puzzles.

Their findings were quite dramatic: Those who played the prosocial games were significantly more likely to be helpful, while those who played the violent games were more likely to be hurtful.