To test the small (r = ~.2) effect of violence on aggression, as well as any possible interactions, the study must be well-powered. We intend to run n=450 subjects. We expect to lose 50 of those subjects to attrition (failed deception, uncooperative behavior, etc). Thus, our final sample size will be ~400. Measures: 2d4d ratio: hands will be scanned. Measurements will be made by two independent raters, using digital software, from the tip of the finger to the lowest crease -- the current best practice for 2d4d measurement. Gameplay variables: As a manipulation check, and to ensure adequate subject participation, the game tracks several gameplay variables: player deaths, player kills, furthest room reached, number of chaingun bullets fired, number of shotgun bullets fired, number of times wounded. Subjects with abnormally low numbers are suspected to have not played the game for the full 15 minutes and will likely be excluded. Aggression measure: After the game, participants receive an insult from their "partner" in the experiment. Participants then get to assign the partner to immerse his hand in painfully cold water as part of an unrelated task. Longer durations assigned reflect greater aggression. Post-Questionnaire: A number of post-questionnaire items are included to measure participants' experience of violent content, game difficulty, and game enjoyment. Other items ask how they felt about their partner's essay evaluation. Other items attempt to measure the participant's familiarity and skill with video games in general, which we have found to be an important moderator for the experience of difficulty (Engelhardt et al., under revision).