Physiological responses to violent game events: Does it matter whose character you kill?

1. THE CENTER FOR KNOWLEDGE AND INNOVATION RESEARCH H E L S I N K I S C H O O L O F E C O N O M I C S Physiological responses to violent game events: Does it matter whose character you kill? J Matias Kivikangas, M.A. & Niklas Ravaja, Ph.D. CKIR, Helsinki School of Economics, Finland email: ravaja@hse.fi

2. Background • Previous studies have shown that different violent and nonviolent game events elicit differential phasic emotion-related psychophysiological responses • Ravaja, N., Saari, T., Salminen, M., Laarni, J., & Kallinen, K. (2006). Phasic emotional reactions to video game events: A psychophysiological investigation. Media Psychology, 8, 343-367. • Ravaja, N., Turpeinen, M., Saari, T., Puttonen, S., & Keltikangas-Järvinen, L. (in revision). The Psychophysiology of James Bond: Phasic Emotional Responses to Violent Video Game Events. Emotion. • Previous studies have also shown that the type of opponent (computer, stranger, friend) influences emotional responses as indexed by tonic psychophysiological measures (mean values during the game session) • Ravaja, N., Saari, T., Turpeinen, M., Laarni, J., Salminen, M., & Kivikangas, M. (2006). Spatial presence and emotions during video game playing: Does it matter with whom you play? Presence: Teleoperators and Virtual Environments, 15, 381-392. • A question arises: • Does it matter whose character you kill? • Do phasic emotion-related physiological responses to violent events differ as a function of opponent type (computer, stranger, friend)?

3. Methods Participants • Participants were 99 (51 male and 48 female) Finnish undergraduates, who ranged from 19 to 34 years of age (mean 23.8 years) • Participants participated in the experiment in groups of three same-sex persons. In each of the 33 groups, two of the participants were friends who knew each other before and one was a person unknown to the others (i.e., a stranger). • In the present study, we used only the self-report and physiological data collected • from the 33 so-called main participants. Game • Super Monkey Ball Jr. (Sega Corporation, Tokyo, Japan) and Duke Nukem Advance (Take 2 Interactive, Berkshire, UK). The games were played with the Nintendo Game Boy Advance console (Nintendo Co., Ltd., Kyoto, Japan). Design • A 2 (Game: Super Monkey Ball Jr., Duke Nukem Advance) 3 (Opponent: computer, stranger, friend) within-subjects design was employed

4. Methods Physiological measures • Facial electromyography (EMG) • Provides a direct measure of the electrical activity associated with facial muscle contractions (an important form of emotional expression) • Zygomaticus major (cheek) muscle area • An index of Positive Affect (PA) • Orbicularis oculi (periocular) muscle area • An index of PA • Corrugator supercilii (brow) muscle area • An index of Negative Affect (NA) • Electrodermal activity (EDA) • The primary psychophysiological index of arousal • As people experience arousal their sympathetic nervous system is activated, resulting in increased sweat gland activity and skin conductance

5. Dimensional Model of Emotion

6. Methods Game Events • The exact onset times of predefined game events were determined by examining the played games, frame by frame, using V-ToolsPro 2.20 software. • We scored four different game events: • The player’s character (own PC) wounded an opponent character (NPC/PC; Opponent Wounded) • The player’s character (own PC) killed an opponent character (NPC/PC; Opponent Killed) • The player’s character (own PC) was wounded by an opponent character (NPC/PC; Own PC Wounded) • The player’s character (own PC) was killed by an opponent character (NPC/PC; Own PC Killed)

7. Methods Data Analysis • Mean values for the psychophysiological measures were derived for one 1-s epoch before each event (Second 1) and for six 1-s epochs after event onset (Seconds 2 to 7). The data were analyzed by the Linear Mixed Models procedure in SPSS with restricted maximum likelihood estimation and a first-order autoregressive covariance structure for the residuals. • Event-related changes in physiological activity were tested using the following orthogonal contrasts: • Linear trend across seconds 1 to 7 (Contrast 1a) • Quadratic trend across seconds 1 to 7 (Contrast 1b) • Friend vs. Stranger × Linear Trend across Seconds 1 to 7 (Contrast 2a) • Friend vs. Stranger × Quadratic Trend across Seconds 1 to 7 (Contrast 2b) • Computer vs. Friend and Stranger × Linear Trend across Seconds 1 to 7 (Contrast 3a) • Computer vs. Friend and Stranger × Quadratic Trend across Seconds 1 to 7 (Contrast 3b)

8. Hypotheses and Results I • H1: The wounding and death of the player’s own character will elicit PA as indexed by increased zygomatic and orbicularis oculi EMG activity. Event: Own PC killed Event: Own PC wounded Contrast 1a, p < .001 Contrast 3a, p < .001 Contrast 1b, p < .001

9. Hypotheses and Results II • H2: Killing or wounding the PC of another human (friend or stranger) will elicit greater PA as indexed by zygomatic and orbicularis oculi EMG activity compared to killing or wounding a NPC. Event: Opponent Killed Event: Opponent Wounded Contrast 3b, p < .001 Contrast 3a, p < .001

10. Hypotheses and Results III • H3: NA as indexed by corrugator EMG activity will increase in the order of killing or wounding a NPC < killing or wounding the PC of a stranger < killing or wounding the PC of a friend. Event: Opponent Killed Event: Opponent Wounded Contrast 2b, p < .001 Contrast 3a, p < .001 Contrast 3b, p < .001 Contrast 2b, p < .05 Contrast 3a, p < .001

11. Hypotheses and Results IV • H4: Physiological arousal as indexed by EDA will increase in the order of killing or wounding a NPC < killing or wounding the PC of a stranger < killing or wounding the PC of a friend. • H5: Physiological arousal as indexed by EDA will increase in the order of the player’s character is wounded or killed by a NPC < the player’s character is wounded or killed by the PC of a stranger < the player’s character is wounded or killed by the PC of a friend. Event: Own PC Wounded Event: Opponent Wounded Contrast 3a, p < .001 Contrast 2a, p < .001 Contrast 3a, p < .001

12. Conclusions • Although counterintuitive, the wounding and death of the player’s own character elicits some aspect of PA • Killing and wounding the PC of another human elicits both greater PA and NA compared to killing and wounding a NPC • Arousal associated with all types of violent game events increases in the order of playing against a computer < playing against a stranger < playing against a friend