Were you hungrier than you thought you were at that restaurant with the richly painted crimson walls? Did you feel particularly calm in that corporate reception area with sea foam-colored wallpaper? Perhaps you didn't immediately notice the physiological effects that the colors in both places may have had on you, but chances are you did experience a shift in appetite or mood induced - or enhanced - by the shade of your environment.
The effects of color on human behavior have been researched by everyone from psychologists to interior decorators. From the ancient Egyptians onward, people have used different colors to illicit different moods and feelings. The ancient Egyptians revered the deep blues and greens of the River Nile, and used blue faience tiles to suggest water running along the floors of their palaces and temples. In the minds of ancient Romans, the color purple was so closely associated with royalty that only Caesar and certain noblemen were allowed to wear it. In more recent times, residents of psychiatric hospitals were thought to be soothed by shades of pale, "institutional" green.
While color is a science, it is not a "hard" science. Rather, it is shaped by human perception - as well as individual preference and experience - so that a certain shade of blue may well induce different feelings and reactions in you than it does in someone else. One means of discussing color and its effects on mood and design is the Bourges system of colors. Developed by graphic artist Jean Bourges and used by many university graphic and interior design programs, the Bourges system divides all colors visible to the human eye into four main groups (reds, yellows, greens, and blues) and quantifies their effects based on both research and common sense.
For example, the red group - which includes scarlet, crimson, pink, and mauve - is considered a "charged" family of hues, inspiring passion and strong feelings. Our eyes pick out reds more readily than any other color, which is why it's used for stoplights and hazard signs.
The Bourges system goes on to ascribe certain intangible moods and attributes to various colors. According to studies done at San Diego State University, viewers generally felt the warm browny-gold of amber to be "mellow, abundant, and fertile" "like beer or wheat fields" or "the color of expensive perfume."