Produce First Study On Violence Desensitization From
led by a pair of Iowa State University psychologists
has proven for the first time that exposure to violent
video games can desensitize individuals to real-life
Carnagey, an Iowa State psychology instructor and research
assistant, and ISU Distinguished Professor of Psychology
Craig Anderson collaborated on the study with Brad Bushman,
a former Iowa State psychology professor now at the
University of Michigan, and Vrije Universiteit, Amsterdam.
authored a paper titled "The Effects of Video Game
Violence on Physiological Desensitization to Real-Life
Violence," which was published in the current issue
of the Journal of Experimental Social Psychology. In
this paper, the authors define desensitization to violence
as "a reduction in emotion-related physiological
reactivity to real violence."
paper reports that past research -- including their
own studies -- documents that exposure to violent video
games increases aggressive thoughts, angry feelings,
physiological arousal and aggressive behaviors, and
decreases helpful behaviors. Previous studies also found
that more than 85 percent of video games contain some
violence, and approximately half of video games include
serious violent actions.
latest study tested 257 college students (124 men and
133 women) individually. After taking baseline physiological
measurements on heart rate and galvanic skin response
-- and asking questions to control for their preference
for violent video games and general aggression -- participants
played one of eight randomly assigned violent or non-violent
video games for 20 minutes. The four violent video games
were Carmageddon, Duke Nukem, Mortal Kombat or Future
Cop; the non-violent games were Glider Pro, 3D Pinball,
3D Munch Man and Tetra Madness.
playing a video game, a second set of five-minute heart
rate and skin response measurements were taken. Participants
were then asked to watch a 10-minute videotape of actual
violent episodes taken from TV programs and commercially-released
films in the following four contexts: courtroom outbursts,
police confrontations, shootings and prison fights.
Heart rate and skin response were monitored throughout
viewing real violence, participants who had played a
violent video game experienced skin response measurements
significantly lower than those who had played a non-violent
video game. The participants in the violent video game
group also had lower heart rates while viewing the real-life
violence compared to the nonviolent video game group.
results demonstrate that playing violent video games,
even for just 20 minutes, can cause people to become
less physiologically aroused by real violence,"
said Carnagey. "Participants randomly assigned
to play a violent video game had relatively lower heart
rates and galvanic skin responses while watching footage
of people being beaten, stabbed and shot than did those
randomly assigned to play nonviolent video games.
appears that individuals who play violent video games
habituate or 'get used to' all the violence and eventually
become physiologically numb to it."
in the violent versus non-violent games conditions did
not differ in heart rate or skin response at the beginning
of the study, or immediately after playing their assigned
game. However, their physiological reactions to the
scenes of real violence did differ significantly, a
result of having just played a violent or a non-violent
game. The researchers also controlled for trait aggression
and preference for violent video games.
conclude that the existing video game rating system,
the content of much entertainment media, and the marketing
of those media combine to produce "a powerful desensitization
intervention on a global level."
(marketing of video game media) initially is packaged
in ways that are not too threatening, with cute cartoon-like
characters, a total absence of blood and gore, and other
features that make the overall experience a pleasant
one," said Anderson. "That arouses positive
emotional reactions that are incongruent with normal
negative reactions to violence. Older children consume
increasingly threatening and realistic violence, but
the increases are gradual and always in a way that is
short, the modern entertainment media landscape could
accurately be described as an effective systematic violence
desensitization tool," he said. "Whether modern
societies want this to continue is largely a public
policy question, not an exclusively scientific one."
researchers hope to conduct future research investigating
how differences between types of entertainment -- violent
video games, violent TV programs and films -- influence
desensitization to real violence. They also hope to
investigate who is most likely to become desensitized
as a result of exposure to violent video games.
features of violent video games suggest that they may
have even more pronounced effects on users than violent
TV programs and films," said Carnagey.