Violent Video Games
Craig Anderson, Department of Psychology
Iowa State University
A Meta-Analytic Review of the Scientific Literature

In total, the research on exposure to video and
television violence suggests that playing violent
video games will increase aggressive behavior
in children and young adults.

This finding is supported by experimental and
field studies among both males and females.

Research indicates also that exposure to video
violence increases psychological arousal and
aggression-related thoughts and feelings.
A Meta-Analytic Review of the Scientific Literature

Exposure to violent games increases
physiological arousal toward aggression.

Exposure to violent games increases
aggressive actions.

Exposure to violent games decreases positive
prosocial (i.e., helping) actions.
A Meta-Analytic Review of the Scientific Literature
Definitions

Violent Media: Depiction of intentional attempts
by individuals to inflict harm on others. An
“individual” can be a non-human character (i.e.,
cartoon) or a real person.

Aggression: Behavior intended to harm an
individual who is motivated to avoid that harm. It
is not an emotion or aggressive thought, plan, or
wish.
Definitions

Violence: Extreme forms of aggression, such as
physical assault or murder. All violence is
aggression, but not all aggression is violence.

The key point is that this research concerns
itself with behavioral outcomes of viewing
extreme violence, not with thoughts or emotions
related to viewing aggressive behavior with
unintentional harm to others.
Video Game Statistics



On average, youths between the ages of 8-18
spend 40 hours per week using some type of
media, not counting school or homework
assignments.
Television is viewed most often, but the
popularity of other video media is rising.
Approximately 10% of youths ages 2-18 play
console and computer video games more than 1
hour per day.
Video Game Statistics

Approximately 15% of men entering college
played at least 6 hours per week of video games
as high school seniors (1999).

Violent video games increased in popularity
during the 1990’s. In games such as Mortal
Kombat, Street Fighter, and Wolfenstein 3D, the
object is to maim, wound, or kill opponents. The
violence is graphic visually and in its sound
effects.
Research Statistics

Five decades of research into the effects of
exposure to violent television and movies have
produced a thoroughly documented and highly
sophisticated set of research findings.

Even brief exposure to violent TV or movie
scenes causes significant increases in
aggression and that repeated exposure of
children to media violence increases their
aggressiveness as young adults.
Theoretical Rationale

According to the General Aggression Model,
long term effects of exposure to violent media
result primarily from the development, rehearsal,
and eventual automatization of aggressive
knowledge structures.

That is, viewing aggression, and in particular,
practicing aggression through interactive video
games, increases aggressiveness as a formed
habit. “You play the game like you practice.”
Theoretical Rationale

Children are more likely to imitate the actions of
a character with whom they identify.

In violent video games the player is often
required to take the point of view of the shooter
or perpetrator.

Video games by their very nature require active
participation rather than passive observation.
Theoretical Rationale

Repetition increases learning. Video games
involve a great deal of repetition. If the games
are violent, then the effect is a behavioral
rehearsal for violent activity.

Rewards increase learning, and video games
are based on a reward system.
General Aggression Model
General Aggression Model
Myths and Facts

Myth 1. Violent video game research has
yielded very mixed results.

Facts: Some studies have yielded
nonsignificant video game effects, just as some
smoking studies failed to find a significant link to
lung cancer. But when one combines all relevant
empirical studies using meta-analytic
techniques, the effects emerge with
considerable consistency.
Myths and Facts

Myth 2. The studies that find significant effects
are the weakest methodologically.

Facts: Methodologically stronger studies have
yielded the largest effects. Thus, earlier effect
size estimates —based on all video game
studies— probably underestimate the actual
effect sizes.
Myths and Facts

Myth 3. Laboratory experiments are irrelevant
(trivial measures, demand characteristics, lack
external validity).

Facts: Arguments against laboratory
experiments in behavioral sciences have been
successfully debunked many times by numerous
researchers over the years.
Myths and Facts

Myth 3 Facts (Continued): Specific
examinations of such issues in the aggression
domain have consistently found evidence of
high external validity. For example, variables
known to influence real world aggression and
violence have the same effects on laboratory
measures of aggression.
Myths and Facts

Myth 4. Field experiments are irrelevant
because aggression measures are based either
on direct imitation of video game behaviors or
are normal play behaviors.

Facts: Some field experiments have used
behaviors such as biting, pinching, hitting,
pushing, and pulling hair, behaviors that were
not modeled in the game.
Myths and Facts

Myth 4 Facts (Continued). The fact that these
aggressive behaviors occur in natural
environments does not make them "normal" play
behavior, but it does increase the face validity
(and some would argue the external validity) of
the measures.
Myths and Facts

Myth 5. Correlational studies are irrelevant

Facts: Correlational studies are routinely used
in modern science to test theories that are
inherently causal. Well conducted correlational
studies provide opportunities for theory
falsification. They allow examination of serious
acts of aggression that would be unethical to
study in experimental contexts. They allow for
statistical controls of plausible alternative
explanations.
Myths and Facts

Myth 6. There are no studies linking violent
video game play to serious aggression.

Facts: High levels of violent video game
exposure have been linked to delinquency,
fighting at school and during free play periods,
and violent criminal behavior (e.g., self-reported
assault, robbery).
Myths and Facts

Myth 7. Violent video games affect only a small
fraction of players.

Facts: Though there are good theoretical
reasons to expect some populations to be more
susceptible to violent video game effects than
others, the research literature has not yet
substantiated this.
Myths and Facts

Myth 7 Facts (Continued). There is not
consistent evidence for the claim that younger
children are more negatively affected than
adolescents or young adults or that males are
more affected than females. Even
nonaggressive individuals are consistently
affected by brief exposures. The literature has
not identified a sizeable population that is totally
immune to negative effects of media violence.
Myths and Facts

Myth 8. Unrealistic video game violence is
completely safe for adolescents and older
youths.

Facts: Cartoonish and fantasy violence is often
perceived (incorrectly) by parents and public
policy makers as safe even for children.
However, experimental studies with college
students have consistently found increased
aggression after exposure to clearly unrealistic
and fantasy violent video games.
Myths and Facts

Myth 9. The effects of violent video games are
trivially small.

Facts: Meta-analyses reveal that violent video
game effect sizes are larger than the effect of
second hand tobacco smoke on lung cancer, the
effect of lead exposure to I.Q. scores in children,
and calcium intake on bone mass. Furthermore,
the fact that so many youths are exposed to
such high levels of video game violence further
increases the societal costs of this risk factor.
Myths and Facts

Myth 10. Arousal, not violent content, accounts
for video game induced increases in aggression.

Facts: Arousal cannot explain the results of
most correlational studies because the
measured aggression did not occur immediately
after the violent video games were played.
Several experimental studies have controlled
potential arousal effects, and still yielded more
aggression by those who played the violent
game.
Myths and Facts

Myth 11. If violent video games cause increases
in aggression, violent crime rates in the U.S.
would be increasing instead of decreasing.

Facts: Three assumptions must all be true for
this myth to be valid: (a) exposure to violent
media (including video games) is increasing; (b)
youth violent crime rates are decreasing; (c)
video game violence is the only (or the primary)
factor contributing to societal violence.
Myths and Facts

Myth 11 Facts (Continued). The first
assumption is probably true. The second is not
true, as reported by the 2001 Report of the
Surgeon General on Youth Violence. The third is
clearly untrue. Media violence is only one of
many factors that contribute to societal violence
and is certainly not the most important one.
Media violence researchers have repeatedly
noted this.
Need for Further Research

Several major gaps remain in the violent video
game literature. One especially large gap is the
lack of longitudinal studies testing the link
between habitual violent video game exposure
and later aggression, while controlling for earlier
levels of aggression and other risk factors.
Indeed, of the four major types of empirical
studies mentioned earlier, this is the only type
missing. There are such studies focusing on
television violence but none on video games.
Need for Further Research

More research is needed to: (a) refine emerging
general models of human aggression; (b)
delineate the processes underlying short and
long term media violence effects; (c) broaden
these models to encompass aggression at the
level of subcultures and nations.