A research paper titled “The dark side of self- and social perception: Black uniforms and aggression in professionals sports.” was published on the American Psychological Association’s website1 in 2012 and analyzed more than 50,000 National Football League (NFL) and National Hockey League (NHL) games over the span of a quarter century.
In the NHL alone, during that time span, players spent nearly a million minutes in the penalty box.
The study states, “Teams with black uniforms are overwhelmingly likely to rank near the top of their leagues in penalties. On those rare occasions when a team switched to black uniforms from another color, the switch was accompanied by a dramatic increase in penalties. This was true in one case even when the change occurred in the middle of the season, so that the "before" and "after" data were provided by the same players, being led by the same coaches, under the watchful eye of the same management.”
As with many studies, it’s hard to pinpoint the “why” of this data but it’s important to note that this isn’t as simple as a home versus away correlation. The researchers pointed out that in 2003 the NHL implemented a rule change that swapped the traditional home team wearing white jerseys to now require road teams to wear white. Through this change they were able to do an A/B test to invalidate the assumption that home versus away was a large impact on the data.
If you are a football fan, you may remember the Rams-Saints pass interference no-call that potentially cost the Saints an appearance in this year’s Super Bowl. If you're not a fan of American football or forgot...here's a clip from ABC News about one of the final plays of the game:
Gameplay and officiating details aside, it's interesting given the topic we're discussing. Saints in dark jerseys: predominantly black and gold. Rams in white jerseys: predominantly white, and blue. The team that committed the alleged penalty was in white and they fully ignored it acting like it never happened.
We found it so interesting that we took a deep dive into the penalty data for the 2018 NFL season for both Super Bowl teams. We assessed the regular season and playoff game data2 for both the LA Rams and the New England Patriots, and their opponents. Then we segmented the data based on dark and light jerseys.
Overall Stats for Rams and Opponents - 2018 Season
|Light Jersey Team||111 penalties, 995 yards|
|Dark Jersey Team||101 penalties, 886 yards|
|Light Jersey Team / Game Ave||6.16 penalties, 55.27 yards|
|Dark Jersey Team / Game Ave||5.61 penalties, 49.22 yards|
Overall Stats for Patriots and Opponents - 2018 Season
|Light Jersey Team||105 penalties, 898 yards|
|Dark Jersey Team||103 penalties, 878 yards|
|Light Jersey Team / Game Ave||5.83 penalties, 49.88 yards|
|Dark Jersey Team / Game Ave||5.72 penalties, 48.77 yards|
The data from both teams during each of their 18 games, which only represents 6.25% of the available data for the 2018 season, tells us that light jerseys have been called for both more penalties (5.7% more) and more penalty yards (7% more) this season.
Some of the dark jerseys, in the case of the LA Rams, weren't actually dark at all. They were bright gold / yellow. Their true dark colors are really just lighter blue. The color psychology of a dark blue and a light blue are drastically different. When they wore their all blue jerseys, the darker of the two dark jerseys, the amount of penalties called per game rose 7% while the penalty yardage rose 28.4%.
People are easily misled when seeing a small subset of data that conflicts with in-depth research. It happens often in user experience testing, marketing assessments, and research in general. We'll cover why that happens and how to work with the results to get a better understanding of the full picture in another blog post, but if you're a New England Patriots fan you should take comfort in the LA Rams choice to wear their blue "penalty" jerseys in the most important game of the NFL season.
1 Frank, M. G., & Gilovich, T. (1988). The dark side of self- and social perception: Black uniforms and aggression in professional sports. Journal of Personality and Social Psychology, 54(1), 74-85.
2 NFL Penalties - 2018 League Penalty Stats. Retrieved from http://nflpenalties.com
Hero image credit: Ian Morton
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