Causal interpretations of long-term associations between habitual exposure to media violence and later real-life violence are based on the observational learning process (Carroll and Bandura, 1987) that media violence leads to children learning long-term “aggressive scripts, interpretational schemas, and aggression-supporting beliefs about social behavior” (Anderson et al., 2003, p. 8) that result in more aggressive personalities (Anderson and Bushman, 2001; Bushman and Huesmann, 2006). Children observe others behaving violently, encode scripts for behaving violently themselves, and encode beliefs that violence is normal, increasing the risk that they will act aggressively or violently. Some studies suggest that repeated exposure to media violence may result in desensitization or a decrease in negative emotional response to violence (Anderson et al., 2003, 2010; Bartholow et al., 2005, 2006; Carnagey and Anderson, 2004; Carnagey et al., 2007; Fuld et al., 2009; Funk et al., 2004; Krahé et al., 2011), thereby reducing psychological barriers to committing violent acts. These theories are in line with some naturalistic specifications of the long-term associations documented in studies, such as the finding that associations are stronger for children than for adults (Bushman and Huesmann, 2006). As previously discussed, some mass murders may in fact be suicides preceded by mass murders. It is not, however, understood if media reporting events such as the ones that occurred in Columbine High School; Platte Canyon High School; an Amish school in Nickel Mines, Pennsylvania; Virginia Tech; and Northern Illinois may inadvertently promote these behaviors (IOM, 2013). Further, no experimental or quasi-experimental research (only research based on observational longitudinal and survey studies) has been carried out to provide definitive evidence that the long-term associations are causal rather than due to unmeasured common causes that select violence-prone youth into high levels of exposure to media violence. However, data from existing studies have shown that long-term associations cannot be solely explained by these unmeasured common causes.
The limited evidence reviewed above is quite clear in arguing that significant relationships exist between violent media exposure and some measures of aggression and violent behavior. For example, it seems clear that there is a relationship between news stories of suicide and imitative suicides. The experimental literature is also very convincing in document-