AUSTIN, Texas, March 25 (UPI) -- Bottling up emotions can make people more aggressive but fatigue does not, researchers in United States found.
Arthur Markman and Todd Maddox, both of the University of Texas at Austin, and Kathleen Vohs and Brian Glass, both of the University of Minnesota, said the study subjects included U.S. soldiers and college students.
Half of the subjects were asked to remain awake for 24 hours before watching the overeating scene from the movie "Monty Python's The Meaning of Life" and the toilet bowl scene from "Trainspotting." The others were permitted to sleep.
Some of the study subjects were then told to watch the movie scenes without visibly reacting -- monitors made sure they didn't cheat -- while the others watched the scenes with no restrictions.
The study, published in the journal Social Psychological and Personality Science, finds those deprived of sleep reacted no differently than those who were well rested, suggesting fatigue does not make people more aggressive as some previous studies have suggested, the researchers said.
However, study subjects asked to suppress their emotions and show no reaction to two disgusting movie scenes were more aggressive than subjects allowed to show their revulsion, the study found.
"Our research suggests people may become more aggressive after they have to control themselves," Markman said in a statement.