"Color psychology is the study of hues as a determinant of human behavior. Color influences perceptions that are not obvious, such as the taste of food. Colors can also enhance the effectiveness of placebos. For example, red or orange pills are generally used as stimulants. Another way in which colors have been used to influence behavior was in 2000, when the company Glasgow installed blue street lights in certain neighborhoods in order to reduce the crime rate. Color can indeed influence a person; however, it is important to remember that these effects differ between people. Factors such as gender, age, and culture can influence how an individual perceives color. For example, males reported that red colored outfits made women seem more attractive, while women answered that the color of a male's outfit did not affect his attractiveness."
- More info: Color psychology on Wikipedia