On the next page we're going to show you an extended abstract for a paper. Please read it as if you were an editor for a scientific journal, deciding on whether to accept the paper. After you read the abstract we'll ask you a few questions.
Entertainment media affects our lives. What behaviors children and adults consider appropriate comes, in part, from the lessons learned from television and the movies. Here we use a randomized control trial in a laboratory setting to test the impact of playing violent video games on aggressive behavior. We recruited a sample of 800 undergraduates from a large Midwestern introductory psychology course to participate in a lab experiment where their aggression was assessed after playing a violent or non-violent single player video game.
Participants were randomly assigned to treatment (violent game) or control (non-violent game) conditions, with 400 participants in each condition. After playing the game for a total of 90 minutes they were placed in unrelated situations where they could anonymously be more or less aggressive towards another person. Our main finding is that participants who played violent video games behaved more aggressively (M = 6.81, SD = 0.51) compared to those who played non-violent video games (M = 6.65, SD = 0.53), t(798) = 4.35, p < .001 (Fig. 1).
Specifically, after playing the game participants were told that someone occupying a neighboring cubicle would compete with them to press a button first in response to a stimulus, and the loser would be subjected to a noise blast, though the neighboring cubicle was in fact empty, and the participant won or lost rounds at random. The intensity and duration of the noise blast was set by the participant ahead of time. When they won, they heard the noise blast in the neighboring cubicle. When they lost, they were subjected to a noise blast of a random intensity and length. We measured their aggressiveness by the length of the noise blast that participants chose to deliver to their opponent when they won the reaction time task.
In the short term, playing a violent video game appears to affect aggression by priming aggressive thoughts. If repeated exposure to violent video games does indeed lead to the creation and heightened accessibility of a variety of aggressive knowledge structures, the consequent changes in everyday social interactions may also lead to consistent increases in aggressive affect.
Suppose you're looking at the results of an experiment involving two groups of people: people who received a treatment and people who were in a control condition. The outcomes in each condition follow a bell curve (or normal distribution), as you might see for people’s heights or weights. The accompanying plot shows the estimated average outcome for each group with error bars showing one standard error above and below the average in each condition.
What is your best estimate of the probability that a randomly selected person in the treatment group has a higher outcome than a randomly selected person in the control group? (A 50% probability indicates no difference in outcomes between the treatment and control groups, on average.)