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CHAPTER 6: Independent Groups Designs 203games increases aggressive affect, cognitions, and behavior. They wondered, however,whether the effects of violent video games would differ when players arepunished for violent game actions compared to when the same actions are rewarded(as in most video games). One hypothesis formed by Carnagey and Anderson wasthat when violent video-game actions are punished, players would be less aggressive.Another hypothesis, however, stated that when punished for their violentactions, players would become frustrated and therefore more aggressive.In Carnagey and Anderson’s studies, undergraduate participantsplayed one of three versions of the same competitive race-car video game(“Carmageddon 2”) in a laboratory setting. In the reward condition, participantswere rewarded (gained points) for killing pedestrians and race opponents(this is the unaltered version of the game). In the punishment condition,the video game was altered so that participants lost points for killing or hittingopponents. In a third condition, the game was altered to be nonviolent andparticipants gained points for passing checkpoints as they raced around thetrack (all pedestrians were removed and race opponents were programmed tobe passive).Carnagey and Anderson (2005) reported the results of three experimentsin which participants were randomly assigned to play one of the three versionsof the video game. The primary dependent variables were measures ofpar ticipants’ hostile emotions (Experiment 1), aggressive thinking (Experiment2), and aggressive behaviors (Experiment 3). Across the three studies, participantswho were rewarded for violent actions in the video game were higherin aggressive emotions, cognitions, and behavior compared to the punish mentand non violent game conditions. Punishing aggressive actions in the videogame caused participants to experience greater hostile emotions (similar to thereward condition) relative to nonviolent play, but did not cause them to experienceincreased aggressive cognitions and behavior.In order to illustrate the process of data analysis, we will examine more closelyCarnagey and Anderson’s results for aggressive cognitions (Experiment 2).After playing one of the three video-game versions, participants completed aword fragment task in which they were asked to complete as many words (outof 98) as they could in 5 minutes. Half of the word fragments had aggressivepossibilities. For example, the word fragment “K I ___ ___” could be completedas “kiss” or “kill” (or other possibilities). Aggressive cognition was operationallydefined as the proportion of word fragments a participant completed withaggressive words. For example, if a participant completed 60 of the word fragmentsin 5 minutes and 12 of those expressed aggressive content, the participant’saggressive cognition score would be .20 (i.e., 12/60 .20).Describing the Results• The two most common descriptive statistics that are used to summarize theresults of experiments are the mean and standard deviation.• Measures of effect size indicate the strength of the relationship betweenthe independent and dependent variables, and they are not affected bysample size.