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Hot hazy weather, violent behavior and the expert witness

Monday, September 5, 2011
posted by Douglas Keene

It’s really hot right now in Texas. We are in extreme drought. This weekend things became heated on my neighborhood email list when someone asked if our HOA had relaxed standards since so many lawns were brown. Multiple others took offense. Finally, someone recommended a cool glass of water for everyone. What’s amusing is that her advice really works to cool down hot tempers.

In truth, the relationship between hot and hazy weather and violent outbursts (so commonly accepted as fact) is pretty murky and uncertain. Scientists are not really sure if violence rises with the temperature or not. A study in Minneapolis recently highlighted by showed that crimes of opportunity do go up as the temperature does but only to a certain level. Once people retreat inside to enjoy their air conditioning, crime falls again.

In Iowa, where it gets a little hotter than in Minnesota, a researcher thought you should take time of day into consideration and reassessed the Minneapolis data—finding a linear relationship with assault rates peaking at the highest temperatures. So, who is right? And who is wrong?

It’s akin to the dueling expert witness battles we often see in pretrial research. Jurors don’t like not knowing who is telling the truth and now, the courts are not enjoying it either. The American Medical Association website recently published an article on how expert witnesses are being held accountable for truth-telling. If the article’s sources have their way, the expert witness as ‘gun for hire’ will be a thing of the past. From the perspective of jurors, this would be a very good thing.  From the perspective of ‘truth’, it may be a bit harder to resolve.

It does not, however, reduce the importance of teaching your expert witness how to speak effectively to jurors. Recently, we were back in East Texas for another patent case and a mock juror who described himself [after hearing the first round of evidence] as a “confused good ol’ East Texas boy” told us:

“I have no trouble judging what’s right and wrong. Just tell me the facts. Don’t sugarcoat it. And I’ll tell you what I think is just.”

It will take a long time for jurors to ‘unlearn’ the perception that experts are simply paid endorsements for either side of the case. (Likely about as long as it will take for all of us to understand that the relationship between heat and aggression has inconsistent scientific support.)  In the interim, preparation, education, and occasionally a tall cool glass of water may be just the ticket.


Baron, R., & Bell, P. (1976). Aggression and heat: The influence of ambient temperature, negative affect, and a cooling drink on physical aggression. Journal of Personality and Social Psychology, 33 (3), 245-255 DOI: 10.1037//0022-3514.33.3.245



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