DURHAM, N.C., March 10 (UPI) -- Soaring summer temperatures make it more likely baseball pitchers will retaliate with a beanball when a teammate is hit by a pitch, U.S. researchers say.
Researchers from Duke University say their study found pitchers are more likely to strike back and peg an opposing batter when the temperature reaches 90 degrees than on cooler days, an article in the Journal Psychological Science reported Thursday.
But if no one has already been hit in the game, then high temperatures have little effect on a pitcher's behavior, the researchers say.
"We found that heat does not lead to more aggression in general," Duke Professor Richard Larrick said. "Instead, heat affects a specific form of aggression; it increases retribution."
"When a batter is hit by the opposing team, his teammates don't know if it was an accident or deliberate," said Larrick, who holds a position in the Duke department of psychology and neuroscience. "We think hotter temperatures make a pitcher more likely to see the action as deliberate and hostile. And once a pitcher feels provoked, hotter temperatures increase feelings of revenge."
The researchers were careful to consider variables such as performance, wild pitches, errors by the other team and even the location of the game.
"It was important to sort out whether heat tends to increase aggressive behavior, such as retribution, or whether it leads pitchers to be less accurate with their pitches," Larrick said.
As a behavioral science expert, Larrick said he wasn't surprised to find a link between heat and aggression. "There are decades of research showing heat leads to aggression, like finding more violent crime in the summer," he said.