Washington, Jun 3 (IANS): People react faster and more forcefully when they see red colour, says a study.

"Red enhances our physical reactions because it is seen as a danger cue," explained study co-author Andrew Elliot, professor of psychology at the University of Rochester, the US.

"Humans flush when they are angry or preparing for attack. People are acutely aware of such reddening in others and its implications."

The intensifying effect of red may have applications for sporting and other activities in which a brief burst of strength and speed is needed. But the authors caution that the colour energy boost is likely to be short-lived.

The study found that when humans see red, their reactions become both faster and more forceful. And people were unaware of the colour's intensifying effect, reports the journal Emotion.

The findings may have applications for sporting and other activities in which a brief burst of strength and speed is needed, such as weightlifting. But the authors caution that the colour energy boost is short-lived, according to a Rochester statement.

But the threat is a double-edged sword, argued Elliot and co-author Henk Aarts, professor of psychology at Utrecht University, the Netherlands.

Along with mobilising extra energy, "threat also evokes worry, task distraction and self-preoccupation, all of which have been shown to tax mental resources", they wrote.

In earlier colour research, exposure to red proved counterproductive for skilled motor and mental tasks: athletes competing against an opponent wearing red were more likely to lose and students exposed to red before a test performed worse.

The study measured the reactions of students in two experiments. In the first, 30 fourth-through-10th graders pinched and held open a metal clasp. Right before doing so, they read aloud their participant number written in either red or grey crayon.

In the second experiment, 46 undergraduates squeezed a handgrip with their dominant hand as hard as possible when they read the word "squeeze" on a computer monitor. The word appeared on a red, blue or grey background.

In both the scenarios, red significantly increased the force exerted, with participants in the red condition squeezing with greater maximum force than those in the grey or blue conditions.