Red versus yellow. Blue versus gray. Those colored jerseys do more than help teammates find their players on the field. The uniforms also help them -- and their fans -- keep up with the action.
If athletes didn't wear different color uniforms, the spectators, refs and teammates would have trouble tracking more than three players at a time, a team of psychologists has demonstrated.
Without color-coding, most people can focus on only three objects simultaneously. But if those objects are in colored groups, humans can perceive up to 35 objects at a time, according to a study in this month's journal Psychological Science.
"That shared color enables you to drastically increase the well-known limit on human attention," said Justin Halberda, an associate professor of psychology at Johns Hopkins University, and one of the authors of the study.
For the study, undergraduate volunteers looked at a series of colored dots flashing on a computer screen for a time too short to count, then estimated the number of dots. For half the time, volunteers were told to focus on a specific group of colored dots. For the other half, they were told to remember as much as possible of what they saw.
When they were told to focus on a specific group, the volunteers counted accurately, even if they only saw the dots for a split second. Even without being told to focus on a specific group, volunteers remained accurate at assessing the number of dots in a group, as long as there were only three colored groups, or less, on the screen at once.
Perhaps most interesting, Halberda said, is that the test revealed that individuals' ability to track groups varied. One volunteer simultaneously tracked the movements of six groups on-screen, while other volunteers could only track two.
The military could potentially develop a test to discern this skill, Halberda said, selecting this person to track enemy movements on a screen.
Or perhaps such a person could become a secret weapon in the next World Cup finals.