Abstract. This study tests two competing hypotheses, one based on the general aggression model (GAM), the other on the self-determination theory (SDT). GAM suggests that the crucial factor in video games leading to increased aggressiveness is their violent content; SDT contends that gaming is associated with aggression because of the frustration of basic psychological needs. We used a 2×2 between-subject experimental design with a sample of 128 undergraduates. We assigned each participant randomly to one experimental condition defined by a particular video game, using four mobile video games differing in the degree of violence and in the level of their frustration-invoking gameplay. Aggressiveness was measured using the implicit association test (IAT), administered before and after the playing of a video game. We found no evidence of an association between implicit aggressiveness and violent content or frustrating gameplay.