Violent electronic games and aggression in adolescents 131
reported measures of aggression, and we analyzed the predictor variables of
aggression.
2. METHOD
2.1 Participants and Procedures
A survey was conducted among Sth to 10th graders at nine schools in
Lisbon, Portugal. Questionnaires were distributed during regular classroom
hours to students who agreed to participate. A total of 111 questionnaires
were excluded from analysis. Of the 666 adolescents who participated,
50.9% were boys (n = 239) and 49.1 % girls (n = 327) between the ages of 12
and 17 years (M= 14.12; DP = US). Participation was voluntary and there
were no incentives offered for participation.
2.2 Measures
A socio-demographic questionnaire was constructed to gather relevant
descriptive information about the participants such as age, socia-economic
status (SES), ethnicity, and level of education. We obtained information
about their starting age with VG and time spent playing VG. For this
measure, students were asked to estimate, on a scale ranging from "never" to
"more than IO hours per week", the average amount of time they spent
playing VG at arcades, computers or consoles, regardless of content.
VGV was measured by the use of a checklist that contained a total of 59
popular shooting and fighting VG. Subjects were asked to rate the time they
spent playing VG during the last six months. The four possible responses
ranged from "never" to "whenever I can". In addition, they were requested
to write down other games (of the same categories) they played during that
period of time. In order to assess the violent content in the liS VG played by
the adolescents, 12 journalists (familiarized with VG) rated the level of
violence on a 5-point unipolar scale. VGV was obtained for each adolescent
by multiplying the mean violence of each game with the total of time they
played: VGV=l:; f;vj.
To measure Aggression, the Portuguese version of the Aggression
Questionnaire12 was used. This scale was created by Buss and PerryJ3 and
contains four subscales of aggression: physical aggression, verbal
aggression, anger and hostility. To measure Personality we used the
Portuguese version of the Junior Eysenck Personality Questionnaire14•1S,
which has scales for Psychoticism, Extraversion, Neuroticism and a lie scale.