Although is it difficult to prove, research indicates that color impacts our psychology. The color green is believed to increase concentration.
A factory in the United States changed the colors of the bathrooms to an unpleasant green and saw production increase by 8%.
Blue conveys trust and reliability, it can also slow your muscle reaction and lower your blood pressure; but red has the opposite affect on a person. Blue street lighting resulted in lower crime rates in Glascow in 2000.
Red can make you hungry, while the opposite color, green, suppresses it. Customers of a coffee house constantly complained about the cool temperature in the room. At that time, the walls were painted a light blue. After changing the color to orange, there were no more complaints.
The color yellow can cause nausea, so it is avoided in airplanes. Black boxes seemed heavier to workmen than green boxes filled with the same material.