Anger has long been associated with competitive situations—that’s why hockey has a penalty box, soccer has red cards, and basketball has flagrant fouls. A new study in PNAS delved into this relationship and found that anger has a complicated effect in competitions, sometimes boosting performance and other times making it worse. What’s more, the results suggest that men actually use anger strategically to get the better of their opponents. This strategy is called the Materazzi effect, after the Italian soccer player Marco Materazzi, who angered rival Zinedine Zidane enough to get him ejected from the World Cup final in 2006.

To examine the competitive consequences of anger, the researchers recruited some of the most outwardly competitive people out there: college men. They randomly paired up 260 participants and assigned each pair to play one of two games.

Strong man

The first game was a test of strength. The two players faced off over two rounds to see which had a stronger grip as measured by a hand dynamometer. After the first round, one player—called the “decision maker”—was given a chance to anger the other: he could assign his opponent to do between zero and twenty minutes of what the researchers called “boring administrative tasks” once the game was over. The other player was notified of the decision maker’s choice before the second round of the game.

The idea was that being assigned bouts of tedious work would anger the player and subsequently affect his performance in the game. The researchers surveyed the players to make sure that being assigned this work did make them mad, and that the decision makers knew it.

To test the effect of anger, the researchers compared players’ grip strength in the second round to that in the first round. Players that were given the full 20-minute assignment performed much better in round two—after they had been angered—than those that were assigned less work, or none at all. In games of strength, being mad actually seems to improve performance.

The duel

But in a second game that tested players’ patience and self-restraint, anger actually impaired performance.

In this computerized “duel” game, players started 20 steps apart, and in each turn they could choose either to take one step forward or to shoot at their opponent. Each time a player stepped forward, their odds of hitting the other player increased, from zero in the first turn to one once they met in the middle. Each player could only shoot once; if they hit their opponent, they were declared the winner, but if they missed, their opponent won. In this game, the optimal strategy would be to shoot when the odds exceeded 0.5. The same anger manipulation was used in this game before the round began.

Angered players didn’t wait to shoot; those that had been assigned the full 20 minutes of work shot first in 70 percent of the trials, and they tended to take their shot before the odds got to 0.5. The less work a player was assigned, the more likely he was to wait to shoot until the odds improved.

It’s clear from these results that anger affects performance, but that the direction of the effect depends on the type of competition. In games of strength, getting mad is advantageous. But when self-control is on the line, anger can be a handicap.

Strategy matters

The researchers uncovered another, subtler, result as well. In each of these games, the decision makers were often using anger to their advantage. In the strength game, the decision makers assigned the full 20 minutes of work in less than half of the trials. But in the duel, the full time was assigned in nearly two-thirds of the trials. Additionally, decision makers assigned more minutes of work in the duel than they did in the strength game. In other words, players were more likely to make their opponents mad in a competition when anger impaired performance compared to one where anger was an advantage.

But there’s a catch: when the angered player was given a 20-minute period to “cool off” before playing, the effect disappeared. This cool-down period offset the consequences of anger in both the strength game and the duel. The decision makers were able to anticipate this effect; in trials with a delay, there was no difference between the two types of games in the number of minutes of work assigned.

Some of these findings may seem intuitive, especially in light of the finding that competitors manipulate anger as a strategy against their opponents. But until these effects are better understood and measured quantitatively, it’s impossible to include them in any sort of theory or model of competition. In a larger sense, this study is just one step along the tortuous path of understanding the complex relationship between emotions and behavior.

PNAS, 2014. DOI: 10.1073/pnas.1313789111 (About DOIs).