The significant result for the IAPS condition was expected, since the IAPS pictures are well validated and designed in such a way to elicit differences in ratings of valence and arousal. The non-significant results of the type of game played and the interaction between game played and the IAPS conditions are probably due to the low power of these tests (.314 and .296). Conducting this experiment with a bigger sample (around 50 participants) could increase the power levels. Although we have a lack of significance and power levels, some consistent small trends are visible as can be seen in figure 4. It is probable that there is no effect of the game played on the valence ratings given to subsequent judged pictures. Moreover it is more likely that for arousal ratings there is an effect of game played. Still it is a small effect, possible to be observed with increased power. EXPERIMENT 2: VIDEO OBSERVATION
In the first experiment video material was gathered of participants playing games. The video clips were then judged by another group of participants. The assumption behind this experiment is that observers can distinguish the non-verbal behavior of participants playing a violent or non-violent game. Furthermore, it is expected that common people, without any special qualification, are able to identify others’ reaction when exposed to such kind of games. Participants
A total of 17 students (9 male and 8 female) from the TU/e were recruited to judge the video clips. Before the experiment, a consent form had to be signed stating that they agreed with being part of this experiment. Experiment Design
The independent variable during this experiment was the collection of observed sets of two videos. The dependent variable was the choice which one of the videos in each set was the one where an aggressive game was being played. The experiment was done in a between-subjects-design. Materials
We decided to take 15 pairs of 20-second video fragments from the first experiment. Each pair consisted of a participant playing a violent and a non-violent game. The video fragments (figure 5) were chosen from a specific part in each game where players were facing extreme conditions in the game according to an experienced gamer. In addition, both parts had to be somewhat at the end of the gaming session, to make sure the participant was in a state of ‘flow’. In addition, the sound was removed and a head view of the gamer was chosen so the movement of the Wii remote control could not be distinguished according to the game played. The videos were projected on a wall with a projector to be watched by the group of participants. A questionnaire was developed in which the participants had to inform which participants were playing the violent game. In addition, the task difficulty was asked on a 5-point Likert scale and an open question was asked to find out which cues were used by participants to perform the judgment.
Figure 5. Sample of video clips watched by participants during experiment 2. Procedure
In small groups (i.e. 3 to 6 people), the participants were informed about the experiment and a consent form was signed. They received instructions that they would watch two short videos and they should mark in a form which video they thought the person was playing a violent game. Following each pair of video fragments, there were about six seconds time to make a choice. After the video fragments, the two additional questions could be filled in. Before the actual experiment, a training session was given with two video fragments to make the participants familiar with the task. The experiment lasted for approximately 10 minutes. RESULTS AND CONCLUSION
The 17 participants each saw 15 videos of people playing the violent videogame. 78% were correctly classified as ‘the participant is playing a violent videogame’. However, some questions about this high percentage have to be raised. When asked for the visual cues that clued our video observers into the fact that they were watching videos from the violent condition they used the following arguments: •
Fast jerky movement of the body;
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Shoulder movement;
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Tense faces; and
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Less blinking of the eyes.
During our own review we concluded that especially the shoulder movement was very visible. Unfortunately, even though the ways of interaction to Link’s Crossbow Training and HotD are very similar, they differ on one detail, and that is a needed quick movement with the arm to reload the gun in HotD. This movement turned out to be easy to spot, even with videos cut down to just the head. It remains to be seen how big of an influence this had on the percentage of correct guesses. However, some interesting conclusions can still be drawn.
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