Red is a powerful color. It's the color of Cupid and the Devil, the color of love and hate. It brings to mind hot-blooded anger and Scarlet Letter shame. It means luck in China, where bridal wear is red, mourning in parts of Africa and sex in Amsterdam's red-light district.
Some of the hue's significance has a biological basis. Many humans get red in the face from increased blood flow when they are angry. A similar process activates a flush of embarrassment or a more flirtatious blush. Seeing red also triggers some surprising behaviors. For instance, drivers blocked in traffic by a red car react faster and more aggressively than drivers barred by vehicles of other colors.
Perhaps the most famous example of the pigment's power comes from animal perception. For hundreds of years matadors have taunted bulls by flashing a red cape. According to bullfighting lore, the color choice is said to help hide bloodstains, but it may have other advantages. Whereas humans are trichromats—meaning that we have three types of retinal cones sensitive to long (red), medium (green) and short (blue) wavelengths—cattle are dichromats: they possess only two kinds of cones.
Perceptual measurements indicate that cattle can discriminate red from green and blue but not green and blue from each other. Moreover, researchers have found that cattle are more active and aroused in red light than in blue or green light. Another study reported that although fighting bulls may charge all sorts of moving objects, the charges carry greater force when directed against warm colors such as red.
In the 1960s the late Spanish-born neuroscientist José M. R. Delgado, then at Yale University, pitted the lure of the red matador's cape against the power of direct brain stimulation by testing whether electronic brain implants could stop a charging bull in its tracks. With the implants linked to a remote control, Delgado climbed into an arena in Córdoba, Spain, and enraged the bull with his cape. His move was a bold one: if Delgado's idea to directly stimulate the caudate nucleus, an area involved in voluntary motion, failed, he would pay the ultimate price. The bull charged—¡Olé!—but Delgado remembered to mash the remote's button in the nick of time, stopping the toro mid-charge. Even if red has the power to lure a bull to attack, little, if anything, can beat direct brain stimulation.
As the examples that follow illustrate, red regularly sways behavior. Charged with social and cultural meanings, it is a powerful enhancer, sending signals that may not really reflect an entity's true nature.
This article was originally published with the title "Seeing Red"
Fire Truck Visibility: Red May Not Be the Most Visible Color, Considering the Rate of Accident Involvement with Fire Trucks. Stephen S. Solomon and James G. King in Ergonomics in Design, Vol. 5, No. 2, pages 4–10; April 1997.
Sporting Contests: Seeing Red? Putting Sportswear in Context. Candy Rowe, Julie M. Harris and S. Craig Roberts in Nature, Vol. 437, page E10; October 27, 2005.
Romantic Red: Red Enhances Men's Attraction to Women. Andrew J. Elliot and Daniela Niesta in Journal of Personality and Social Psychology, Vol. 95, No. 5, pages 1150–1164; November 2008.
Does Red Lipstick Really Attract Men? An Evaluation in a Bar. Nicolas Guéguen in International Journal of Psychological Studies, Vol. 4, No. 2, pages 206–209; June 2012.
ABOUT THE AUTHOR(S)
Susana Martinez-Conde is a professor of opthalmology, neurology, and physiology and pharmacology at SUNY Downstate Medical Center in Brooklyn, N.Y. She is author of the Prisma Prize-winning Sleights of Mind, along with Stephen L. Macknik and Sandra Blakeslee. Their forthcoming book, Champions of Illusion, will be published by Scientific American/Farrar, Straus and Giroux.
Stephen L. Macknik is a professor of opthalmology, neurology, and physiology and pharmacology at SUNY Downstate Medical Center in Brooklyn, N.Y. Along with Susana Martinez-Conde and Sandra Blakeslee, he is author of the Prisma Prize-winning Sleights of Mind. Their forthcoming book, Champions of Illusion, will be published by Scientific American/Farrar, Straus and Giroux.