These shootings do not fit the common preconception of violence in America. They did not happen in the often violent inner-city schools but in relatively small towns in the backwoods: in central Mississippi, in south-western Kentucky, and now in northern Arkansas. Although much violence in America is concentrated among blacks, these schools are predominantly white. As for those who think they illustrate a trend of increasing juvenile violence in the US, they are wrong: juvenile crime has started to fall in the past two years.
Nor are American schools necessarily violent. According to a study released last week, the incidence of violence in schools has changed little over 20 years.
Even excluding these explanations, the three school shootings have enough in common to give analysts material to work on. Noting that all the recent shootings took place in southern states, one Arkansas academic blamed "Southern culture" where guns were a fact of life, the right to carry arms was strongly defended and on public display, hunting was a common pastime, and children had easy access to weapons.
Others blamed lax parental discipline which gave children the idea they could settle disputes violently, and yet others lamented what they saw as stifling peer pressure in schools where 10- and 11-year olds are already dating and, as apparently in this case, wreaking vengeance for favours spurned.
And while juvenile crime may be falling, the level of violent crime among juveniles has risen. A New York psychologist said: "Now kids have access to money, drugs, alcohol and weapons. Things have changed, and they have the opportunities to do these horrible things."
Surprisingly, perhaps, the standard explanation after such multiple shootings - that the young perpetrators were inordinately influenced by films, television or violent video-games - has been heard less than on previous occasions. Although many American parents seem concerned to the point of paranoia that their children should be sheltered from violence and sex on television or the Internet, there is growing recognition that second-hand violence does not automatically foster violent behaviour.
Several experts noted that the perpetrators in all three recent shootings seemed to be loners, with some latent predisposition to violence or past problems in schoolwork and socialising.
"Normal kids," said one yesterday, "don't do this."Reuse content