Can Uniform Color Color Aggression? Quasi-Experimental Evidence From Professional Ice Hockey

Abstract

Is uniform color related to aggressive behavior? Prior research has produced mixed results comparing the effects of black (vs. colored) uniforms on aggressive penalties in the National Hockey League (NHL), and the effect of white (vs. colored) uniforms remains unexamined. Luckily, the NHL has conducted multiple quasi-experiments with uniform (jersey) color over time. To examine the color–aggression link, the authors analyzed the last 25 seasons of NHL penalty-minute data (649 seasons from 30 teams collapsed across 52,098 games). When teams wore black jerseys, they were penalized more than when they did not ( d = 1.19; Study 1). When teams switched to wearing colored jerseys at home games, they were penalized more than when they wore white jerseys at home games ( d = 0.83; Study 2). Collectively, these quasi-experimental findings suggest that black jerseys are associated with more aggression and that white jerseys are associated with less. The authors discuss possible causes for these color-aggression effects.