The mass shootings in Tucson over the weekend led to all sorts of exercises in arm-chair psychology. The media was quick to portray the shooter Jared Lee Loughner as unhinged and paranoid, digging up his Internet ravings and probing former friends and classmates for detailed testimonials of his bizarre statements and aggressive behavior. And, following its polarization meme, we were subjected to endless accounts of how America's heated and "vitriolic" political climate helped to trigger such action.

But what can psychology tell us about the specific ways that regional, locational, and geographic factors can affect gun violence and mass shootings in particular?

I was surprised by what I found out when I asked my colleague Jason Rentfrow, the distinguished social psychologist at Cambridge University, about this. While some continue to attribute gun violence and mass shootings to hot climates in the U.S. and elsewhere -- "Living in a hot and uncomfortable climate makes people irritable and rates of violence go up," Rentfrow summarizes -- the preponderance of studies focus on a "culture of honor" that is especially pervasive in Southern and Western states. This is something that pundits and commentators need to take a good deal more seriously because, if it is correct, and a considerable body of research suggests that it is, it suggests that deep-seated regional and cultural factors play a substantial role in mass violence.

The classic study of the subject is by Richard Nisbett, a social psychologist at the University of Michigan. In his paper "Violence and Regional Culture," published in the American Psychologist in 1993, Nisbett examined the higher rate of violence in the U.S. south, which he notes has been established since the time of revolution. After considering possible explanations having to do with poverty, slavery, and even the region's hotter climate, he found a different answer in a cultural vestige of pastoralism: a deep "culture of honor" in which residents place an extraordinary value on personal reputation, family, and property. Threats to these things provoke aggressive reactions, leading to higher rates of murder and domestic violence. Here is how Nisbett himself explains it:

Southerners do not endorse violence in the abstract more than do Northerners, nor do they endorse violence in all specific forms of circumstances. Rather, they are more likely to endorse violence as an appropriate response to insults, as a means of self protection, and as a socialization tool in training children. This is the characteristic cultural pattern of herding societies the world over. Consistent with the culture-of-honor interpretation, it is argument-related and not felony-related homicide that is more common in the South...

There is another sense in which the culture of honor might turn out to be self-sustaining or even capable of expanding into mainstream culture. The culture is a variant of warrior culture the world over, and its independent invention countless times (Gilmore, 1990), combined with the regularities in its themes having to do with glorification of masculine attributes, suggests that it may be a particularly alluring stance that may  be capable of becoming functionally autonomous. Many observers (e.g., Naipaul, 1989; Shattuck, 1989) have noted that contemporary Southern backcountry culture, including music, dress, and social  stance, is spreading beyond its original geographical confines and becoming a part of the fabric of rural, and even urban, working-class America.

Perhaps for the young males who adopt it, this culture provides a romantic veneer to everyday existence. If so, it is distinctly possible that the violence characteristic of this culture is also spreading beyond its confines. An understanding of the culture  and its darker side would thus remain important for the foreseeable future.

Rentfrow also pointed me to a more recent study by Ryan P. Brown, Lindsey Osterman, and Collin  Barnes of the University of Oklahoma, published in Psychological Science in 2009, which reinforces Nisbett's findings and suggests that the culture of honor plays a particularly significant role in high school violence. The study found that the culture of honor to be significantly associated with two indices of school violence: the percentage of high school students who reported having brought a weapon to school during the past month; and the prevalence of actual school shootings over a 20 year period. The authors summarize their key findings this way:

Some researchers have suggested that the apparent relationship between general acts of violence and the culture of honor in the United States might be at least partially explained by demographic differences between Southern and Western states, on the one hand, and Northern and Eastern states, on the other, rather than being a product of cultural differences (Anderson & Anderson, 1996). Indeed, culture-of-honor states are typically hotter, more rural, and poorer than non-culture-of-honor states, and any of these differences might explain the link between culture of honor and violence.

However, the state-level demographic variables that we examined--  which included temperature, rurality, social composition, and indices of economic and social insecurity--were unable to account for the association between culture of honor and our school-violence indicators, and also were inconsistent predictors of the school-violence variables across the two studies. This marks an important difference between these indicators of school violence and more general indicators of violent crime among adults, which typically show stronger and more consistent associations with temperature, rurality, and environmental-insecurity measures similar to the ones we used (Anderson, 1989; Baron & Straus, 1988; Cohen, 1996; Lee, Bankston, Hayes, & Thomas, 2007).

This difference suggests that school violence is a somewhat  distinct form of aggression that should not be viewed through  standard lenses. That the culture of honor appears to be such a robust predictor of school violence supports the hypothesis that school violence might be partially a product of long-term or recent experiences of social marginalization, humiliation,  rejection, or bullying (Leary et al., 2003; Newman et al., 2005),   all of which represent honor threats with special significance to  people (particularly males) living in culture-of-honor states.

I am amazed how well this explanation seems to fit the emerging facts and context of the mass violence in Tucson. I don't mean the obvious fact that the shooting happened in a Sunbelt city -- Tucson is a sophisticated college town, not the sort of rural backwater Nisbett had in mind. It is the nature of the culture of honor itself  and the way it acts on and through marginalized young males, just like Loughner. The culture of honor, as Nisbett describes it, sees violence as an "appropriate response to insults" and as "a means of self-protection."

Numerous media reports note that Loughner grew more obsessed with Congresswoman Giffords after he felt she did not give him a respectful answer to the question he asked her at an earlier forum. Then there are the results of the University of Oklahoma study which finds the culture of honor to be a particularly robust predictor of high school violence, especially among young males who have been marginalized, bullied, rejected, or faced other "honor threats." And, Nisbett's some two-decades-old warning that the culture of honor is not something that is necessarily geographically bounded but seems to spreading into broader aspects of young male working-class enclaves in both urban and rural communities is as prescient as it is chilling.

My next post will cover the social, economic, political, and cultural as well as psychological factors that are associated with gun violence and firearm deaths across the 50 U.S. states.