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August 7, 2011

"The Hazy Science of Hot Weather and Violence"

The title of this post is the headline of this recent Wired magazine piece (which was discussed in this recent NPR segment).  Here is how the piece starts:

The link between violence and hot weather is so intuitive that it’s embedded in our language: Hotheads lose tempers that flare, anger simmers and comes to a boil, and eventually we cool down.  So what does science have to say?  Do tempers truly soar with temperature?  

The answer, appropriately enough for these triple-digit days, is hazy and hotly contested.

To be sure, extensive literature exists on hot weather and violence, stretching from poorly controlled regional studies in the late 19th and early 20th centuries — oh, those hot-blooded southerners! — to more sophisticated modern analyses.  This doesn’t just apply to the United States, but countries like England and Wales and New Zealand.  But whether weather is cause or coincidence is difficult to determine.

Perhaps the most detailed studies, led by psychologists Ellen Cohn and James Rotton of Florida State University, involved violent crime over a two-year period in Minneapolis, Minnesota.  Cohn and Rotton classified assaults according to time of day, day of week, and month and temperature.  They ultimately concluded that violence rose with temperature, but only to a point.

Around 80 degrees Fahrenheit, assault rates started to fall, a trend that dovetailed with a hypothetical explanation for heat-induced violence in which being uncomfortable provokes competing tendencies of both aggression and escape.  At low to moderate levels of discomfort, people lash out, but at high levels they just want to flee.

But the results also fit with a sociological rather than psychological explanation.  According to so-called Routine Activities Theory, many forms of violent crime are functions of social opportunity, and increase when more people spend more time outside.  When it becomes so hot that people retreat inside, crime falls.  Cohn and Rotton supported this explanation.

Cohn and Rotton’s interpretations of the numbers, however, were contested by Iowa State University psychologist Craig Anderson, who felt they hadn’t fully accounted for time-of-day effects.  His own take on the data produced a linear relationship between heat and violence, with assault rates peaking at the highest temperatures.

August 7, 2011 at 04:31 PM | Permalink


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The Weather Excuse.

Now air conditioning should become an entitlement.

Posted by: Supremacy Claus | Aug 8, 2011 7:09:01 AM

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