(Medical Xpress) -- Violent media -- films, TV, videogames -- can encourage aggression, and lots of research says so. But psychologists haven't spent as much time looking at the ways media with more socially positive content help suppress meanness and prod us toward cooperation, empathy, and helpfulness. When and why might a game or a movie mobilize our better angels and squelch our devils?

A review of the literature, including his own work, by psychologist Tobias Greitemeyer at the University of Innsbruck in Austria sorts out those questions and proposes a model to explain the cognitive processes underlying their answers. The article will be published in the August issue of Current Directions in Psychological Science, a journal of the Association for Psychological Science.

Greitemeyers own studiesmany of them conducted with Silvia Osswald of Ludwig Maximilians University, in Germanyhave affirmed that prosocial media content abets friendlier, more forgiving attitudes and behavior. In one experiment, for instance, some participants played a videogame called Lemmings, in which players guide little creatures through dangers to safety, while others played the morally and emotionally neutral game Tetris. Afterwards, the first groups members were more likely to intervene in a simulated scene in which a man bullied and hurt his ex-girlfriend. The prosocial game group also more quickly identified socially positive words over neutral words (i.e., help versus run) amid nonsense words on a screen. Those who played a neutral game showed no difference in the time it took to select the words. This, says Greitemeyer, is evidence that the experience of playing the nicer game makes benevolent thoughts more accessible in the mind.

Prosocial game playing also suppresses aggressive thoughts and feelings. In another study, participants also played either a helpful, cooperative game or a neutral one. Asked to complete storiesin one, a friend arrives late to a movie date and doesnt apologizethe former were less likely to evince angry, mean, or vengeful emotions. A story of Paris Hiltons jailing after racing her car through Hollywoods streets elicited more empathy and less schadenfreude, or pleasure at anothers misfortune, from those whod played the friendlier game. Songs with loving or peaceful lyrics also have been shown to instigate charitable giving and more generous tipping.

To explain these phenomena, Greitemeyer calls on the General Learning Model, which posits that personal traits, such as sex or education, either act independently or interact with situational conditions to affect thoughts, feelings, and arousal. Introduce media of varying contents, and either negative or positive cognition and emotion can be encouraged or discouraged, leading to different behaviors.

Noting the high prevalence of violence in all media, including those for children, as well as the voluminous research on it, Greitemeyer writes: It is my hope that researchers will also address to what extent acts of benevolence in everyday life are precipitated by exposure to prosocial media. Evidence of such salutary effects can only give sciences imprimatur to a kinder, gentler world.