Correlations between Heat and Hostility by M.Pitter

In Act I Scene I of William Shakespeare’s Henry IV, the Earl of Westmoreland reckoned that the cause of the recent violence was due to the hot climate of the summer season. In Shakespeare’s famously enigmatic syntax, Westmoreland reflects and reasons:

“On Holy-rood day, the gallant Hotspur there,
Young Harry Percy and brave Archibald,
That ever-valiant and approved Scot,
At Holmedon met,
Where they did spend a sad and bloody hour,
As by discharge of their artillery,
And shape of likelihood, the news was told;
For he that brought them, in the very heat
And pride of their contention did take horse,
Uncertain of the issue any way.” (I.i.53-62)

This monologue here recounting the “sad and bloody hour” and how it was spent “in the very heat / And pride of their contention” suggests that there is a link between heat (whether it be physical or figurative) and the belligerence of people.

credit: M. Pitter/In Parentheses
credit: M. Pitter/In Parentheses

This is not unheard of. We have probably witnessed impatience and irritability acted upon by our fellow people during times of high temperatures. For instance, the Watts Riots ‘officially’ took place in 1965 between August 11 and August 17, the Bastille was stormed on the 14th of July, the West Indian Labor Day Parade in Brooklyn has been notoriously marred by having acts of violent stabbings and shootings occur year after year. In Spike Lee’s Do the Right Thing, the links between heat and hostility are deeply explored. At one point, one of the old men characters, Sweet Dick Willie, sitting in front of a red wall says blatantly that:

“It’s so hot, makes you wanna kill somebody.”

exhausted by the heat. Another character ML elaborates on this notion saying:

“Well, gentlemen, the way I see it, if this hot weather continues, it’s going to melt the polar caps and the whole wide world. And all the parts that ain’t water already will surely be blooded.”

Sweet Dick Willie (middle) and ML (left)
ML (left) and Sweet Dick Willie (middle)

Across generations and traditions, intense, constricting and unpleasant heat is the catalyst for short tempers and behavioral trigger happiness.

In the physical sciences, applying heat to an object gives this object more energy. (To define energy concretely, we can say that energy is an entity of physics that is broadly represented such that it could be applied to many different scenarios and exhibit various forms beyond just heat and temperature. For example, electromagnetic radiation [radiowaves, microwaves, infrared, visible light, UV rays, X-rays and gamma rays] is a type of energy that does not always contribute to changes in temperature. Sound, whether it comes from a collection of instruments, a car accident, or a voice, is a form of energy. For our purposes, let us consider energy as a scalar quantity that can be transferred: given and received, absorbed and expelled, gained and lost: transferred yet conserved.) Applying heat to solid water (an ice cube) will cause the ice cube to develop a liquid identity. As a liquid, water behaves more ‘energetically’ in the sense that if we put it in a small container, it will immediately proceed to fill the shape of the container (depending on the quantity dispensed) as opposed to the ice cube that would sit localized in one position within this container. Now, applying more heat to liquid water will cause it to develop a gaseous identity. It will turn into a vapor. As a vapor, water behaves even more ‘energetically’ than when it is in liquid and solid form. If I am holding a bucket of liquid water and someone else is holding a large enclosed bulb of water vapor and if we both agreed to release our contents at the same time, the liquid water would fall and splash onto the ground and the water vapor would float, dance and stream upward into the sky and away. So from these examples of how the application of higher and higher temperatures (a form of energy) changes the form of water (H2O), we can deduce that heat, as we know it in the climate, has an effect on the configuration of molecules within the objects with which it interacts. As described earlier, the more energetic an object behaves, the more freely it moves. Recall the differences in character between solid, liquid and vapor water. Physically, temperature is directly related to the velocity (or more specifically the kinetic energy which depends on both mass and velocity) of the molecules composing an object. The higher the temperature, the faster the molecules move and so the more ‘energetically’ the object behaves.

credit: M. PItter/In Parentheses
credit: M. Pitter/In Parentheses

Applying this specific notion of increased energy to human behavior, we can begin to make sense of how high temperatures could induce within people dispositions of discomfort. Consider a person as a shaken bottle of soda. How agitated and near the brink of explosion a person could be when subject to incessant heat especially in crowds of people that create more heat. The phases of heat that exceed comfort often promote violence among people.

credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses

Research conducted at Kent State University in Ohio by geographer and sociologist Scott C. Sheriden and Paul Butke entitled “An Analysis of the Relationship between Weather and Aggressive Crime in Cleveland, Ohio” reveals some interesting insight. After presenting a graph showing that the highest mean number of crimes among the seasons occur diurnally during the summer, Sheriden states that:

“In examining the apparent temperature–crime relationship across the entire season cycle, a positive linear relationship between all aggressive crime types and daily mean apparent temperature is observed (Fig. 3). For the aggregate of all aggressive crime as well as for all individual categories examined in this study, mean crime levels are approximately 50% higher when mean apparent temperature is 25-degrees Celsius compared with when it is -10-degrees Celsius.”

His findings are supported by the fact that because of the high temperatures and the longer periods of sunlight during the summer, people spend more time outside and hence the probability of violent contact between humans is higher. Other approaches to the idea of the temperature-crime relationship were taken by physiologist Craig Anderson in his research that incorporated more (of course) physiological and psychological insight on heat-induced violence.

The simple discomfort that heat creates for people induces within them an aggressive disposition that, given the particular situation, may be acted upon:

“Heat-induced discomfort makes people cranky. It increases hostile affect (e.g., feelings of anger), which in turn primes aggressive thoughts, attitudes, preparatory behaviors (e.g., fist clenching), and behavioral scripts (such as “retaliation” scripts). A minor provocation can quickly escalate, especially if both participants are effectively and cognitively primed for hostility by their heightened level of discomfort. A mild insult is more likely to provoke a severe insult in response when people are hot than when they are more comfortable. This may lead to further increases in the aggressiveness of responses and counter-responses. An accidental bump in a hot and crowded bar can lead to the trading of insults, punches, and (eventually) bullets.”

He goes on to say that hot weather contributes to increases in heart rate, it triggers “fight-or-flight” impulses and it also increases testosterone production which often succeeds in tipping the balance to the “fight” impulse.

credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses

When temperatures are quite low, one could simply arrange various articles of clothing in layers until personal warmth is achieved. But when temperatures are high, undressing into the nude can be really nice but it still doesn’t necessarily relieve one from the heat. So this idea of being trapped in discomfort gives a twisted incentive to be hostile, to be less cognizant of order, or at least less concerned with maintaining any sort of ‘order’. Feelings of madness creep up to overthrow balance and poise.

credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses

There is still much speculation involving the exact connection between temperature and behavior. In places where the temperatures are usually high all year around, it may be an overstep to apply these findings there. But if we look at places where heat is seasonal, our intuition, our traditions and our research usually tell us that with the heat comes conflict and a sort of increase in chaos. In the same way liquid water flows due to its increased energy, the passions and hysteria of people may flow due to the increase in ‘energy’ within them and those around them to the point where someone wants to drop everything and shout: GODDAMN, IT’S HOT!

credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses
credit: M.Pitter/In Parentheses


Anderson, Craig.

Halliday, Resnick and Walker. Fundamentals of Physics, 9th Ed., Extended Version. John Wiley and Sons, New York, 2011.

Hill, John W., McCreary, Terry W., Perry., Scott S, and Petrucci, Ralph H. General Chemistry. 4th Edition. Pearson Prentice Hall, 2005.

Keim, Brandon.

Sheridan, Scott.


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