"Red is any of a number of similar colors evoked by light consisting predominantly of the longest wavelengths of light discernible by the human eye.Red catches people's attention, and is often used either in a negative way to indicate danger and emergency, or in a positive way in advertising to gain more viewers, or in nature, as a ripe fruit announces its readiness with its red color. Several studies have indicated that red carries the strongest reaction of all the colors, with the level of reaction decreasing gradually with orange, yellow, and white, respectively."
* * information from Wikipedia
