With the advent of the really hot weather hereabouts, several articles (from the "no kidding" department) have been written about the connection between hot weather, reduced brain activity, and violent behavior. Warm weather makes it hard to think straight, and if a person has impaired cognitive functioning, he/she often reverts to more primitive behavior.

As the theory goes, in hot weather the blood rushes to the capillaries in your skin in order to cool you off. Your blood pressure rises to meet the demand, and so does your temper. Hence the increased violence, especially when heat and humidity combine to make the miserableness factor worse.

Scientific American takes it one step further and posits that cold weather increases brain activity ("wakes up your mind" is how they put it) as the demand for blood elsewhere is reduced.

I'm not so sure that the theory is correct. My observation has been that either extreme--very sweaty hot or achingly cold--reduces the amount of ideation, perhaps not identically, perhaps not for the same reasons.

It would be equally possible to posit that a person eats more in cold weather, sending the blood flow to the digestive system to deal with the processing of food and the distribution of nutrients via the blood stream, thereby reducing the circulation to the brain and the extremities both.

Personally I find that extremes of either sort demand so much of my attention to coping with the bodily needs to keep warm or cool off that I am distracted from quiet thinking, for which moderate temperatures and enough comfort to be able to relax the body are ideal.

The article points out that "the two processe--correcting for excessive heat and unwanted cold--are not equally taxing, however; cooling the body down seems to require more energy than warming it up." Thus reducing the amount of glucose available for brain work.

If I have a choice, I'd rather be cold than hot.