THURSDAY, July 6, 2006 (HealthDay News) -- When soccer fans gather Sunday to watch France and Italy do battle in Berlin during the World Cup finals, new research suggests the enraptured audience will be better able to follow every artful pass and blistering shot on goal because of the brilliant, crisp colors each team will wear.
Fact is, without the help of color, the human brain can't pay attention to more than three moving objects at once, concluded a team of neurological researchers reporting in the July issue of Psychological Science.
Grouping even a vast number of objects or people together by color makes all the difference, the researchers said.
"That's a new finding -- that humans can attend to more than three items if those items form a single set," said study co-researcher Justin Halberda, an assistant professor of psychological and brain sciences at Johns Hopkins University. "The set itself can then function as an individual," he added.
According to Halberda, a variety of tests have proven over and over that humans of all ages, as well as other primates, can't keep their attention fixed on more than three items at once in a given visual field. "We've never seen a case where that wasn't true," he said.
So, that finding begged the question: How can humans follow and enjoy team sports, which often contain dozens of players running in various directions at once? Halberda and his colleagues suspected the answer lay in the fact that societies have historically clothed opposing teams -- even opposing soldiers -- in different colors.
"Color is processed very early [by the brain]," Halberda said, so it makes sense that it would function as a nearly immediate cue to who belongs to what.
In their study, the Hopkins scientists had undergraduate volunteers view a series of colored dots that flashed before their eyes on a computer screen for just a half-second -- too short a time for counting.
The dots were arranged randomly, but some shared a color -- say, red or green. The researchers would sometimes warn the volunteers ahead of time to "watch for the red dots," for example. But in other experiments, the volunteers were given no such warning and were simply told to pay attention to the screen.
The researchers then asked the participants to recall how many dots of a specific color they thought they had seen.
The result: Participants did well at estimating the number of dots when told in advance which colors they should pay attention to, demonstrating they could pay attention to large numbers of items based on color alone. In fact, participants were accurate in estimating the number of color-specific dots even when the total collection consisted of a wide spectrum of colors.
Participants did less well when they weren't told beforehand which color they should fix their attention on. They were still able to recall, with some accuracy, the number of dots of a certain color -- but only when the whole array was comprised of dots of three colors or less.
Translating these findings from the computer screen to the playing field isn't a great leap, Halberda said.
"If you consider something like the World Cup, you have this big green field, and you're not so much tracking the items as they move, in terms of color -- it's just seeing them all in the first place," Halberda said. "So, England's bright white jerseys jump out from the green background and that makes them easier to pay attention to."
But humans also have an upper limit when it comes to paying attention to sets, Halberda said, and it's the same as their tolerance for tracking individual objects -- three.
That could explain why, throughout history, people have stuck to games with just two opposing teams. "Our research suggests that if a game was devised with four teams playing simultaneously, it would just be too many for any spectator, coach or player to pay attention to," Halberda said.
He said his team is now trying to find out whether other qualities are as easily gathered into sets as is color. Already, orientation -- objects that stand up vertically rather than lie horizontally -- looks promising, he said. Other characteristics, such as shape or gender, take longer for the brain to process and may be less useful, Halberda said.
Color does seem to be especially useful, he said, not just in sports but for a host of everyday challenges, such as playing cards, scanning the TV guide, or arranging filing cabinets at the office.
The ability of the human mind to supersede the "three-object rule" and clump together many similarly colored items into sets could have evolutionary roots, Halberda added.
"Let's say you were a hunter-gatherer, and you wanted to compare which tree had the most oranges," he said. If primitive man could only pay attention to three oranges at a time, that task would have been enormously difficult.
"But we have this system, and now you can look up at a tree and simultaneously attend to all 70 oranges," Halberda said. "Then, you could say, 'Yeah, that's a good tree, I'll climb that one.' It's a radical increase in efficiency," he said.
More information
Learn more about the brain at the National Institute of Neurological Disorders and Stroke.
