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Unformatted text preview: ary and sufficient” position, as is the 45-year-old
two-pack-a-day cigarette smoker who notes that he still does not have lung cancer. But both are
wrong in inferring that their exposure to their respective risk factors (violent media, cigarettes) has Anderson, Berkowitz, Donnerstein, Huesmann, Johnson, Linz, Malamuth, & Wartella 14 not causally increased the likelihood that they and people around them will one day suffer the
consequences of that risky behavior.
Third, a developmental perspective is essential to an adequate understanding of how media
violence affects youthful conduct and to the formulation of a coherent public-health response to this
problem. Most youth who are aggressive and engage in some forms of antisocial behavior do not
go on to become violent teens and adults. However, research has shown that a significant
proportion of aggressive children are likely to grow up to be aggressive adults, and that seriously
violent adolescents and adults often were highly aggressive and even violent as children. In fact,
the best single predictor of violent behavior in older adolescents and young adults is aggressive
behavior when they were younger (Huesmann & Moise, 1998; Tremblay, 2000). Thus, influences
that promote aggressive behavior in young children can contribute to increasingly aggressive and
ultimately violent behavior many years later. It is therefore important to identify factors—including
media violence—that, singly and together, may play a role in these outcomes in childhood.
Fourth, it is important to avoid the error of assuming that small statistical effects necessarily
translate into small practical or public-health effects. There are many circumstances in which
statistically small effects have large practical consequences. Perhaps the most relevant
circumstances are when small effects accumulate over time and over large proportions of the
relevant population. For example, when Abelson (1985) asked a group of Yale University
psychology scholars knowledgeable both about the concept of statistical variance and about
baseball “to estimate what percentage of the variance in whether or not the batter gets a hit is
attributable to skill differentials between batters” (p. 131), he found that these statistically
sophisticated psychologists greatly overestimated the variance due to skill differences. The median
estimate was 25%, whereas the correct statistical answer is actually about 0.3%. But, this small
effect of batting-skill differences has a huge impact on outcomes such as team win/loss records,
career runs batted in, league championships, and World Series championships, because even small Media Violence 15 differences in batting skill accumulate across large numbers times at bat within a season and across
Similarly, even small statistical effects of media violence on aggressive behavior can have
important societal consequences for at least three different reasons. First, a large portion of the
population (almost everyone, in fact) is exposed to this risk factor (accumulation across a large
population). Second, the deleterious effects of exposure to media violence are likely to accumulate
(via learning) within the individual with repeated exposure. Third, even short-lived effects of a
single exposure (via priming effects--see the Theoretical Explanations section) can add significant
amounts of aggression and violence to society because at any given waking hour a large portion of
the population either is currently being exposed to violent media or has been exposed to such
violence within the past 20 min.
Medical scientists and public-health officials seem to have avoided the problem of underestimating the public health importance of small effects by translating their findings into cancer
rates or heart attack rates or death rates for the entire U.S. population, but behavioral scientists have
not traditionally done this type of population-rate translation. Thus, people are frequently shocked
to learn that many behavioral science effects are considerably larger than key medical science
effects that are deemed extremely important (e.g., Bushman & Huesmann, 2001). For example,
Rosenthal (1990) reported that the major study on aspirin’s ability to reduce heart attacks was
stopped prematurely because the initial results were so strong that it was deemed ethically
irresponsible to continue giving placebos to the control group; aspirin's effect accounted for about
0.1 % of the variance. Our point: Conclusions about small statistical effect sizes need to be made
with caution and in this broader context.
Finally, it must be recognized that the firmest evidence about the effects of media violence, or
any other presumed causal influence, on aggression is provided by true experiments in which
participants are randomly assigned to conditions experiencing different "doses" of the factor under Anderson, Berkowitz, Donnerstein, Huesmann, Johnson, Linz, Malamuth, & Wartella 16 investigation. There have be...
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This note was uploaded on 04/14/2013 for the course ELECTRICAL 205 taught by Professor Tom during the Spring '13 term at American University in Cairo.
- Spring '13
- The Land