Found this a few moments ago and thought it was interesting. It is about how the brain responds to color:

Color stimulates the brain in different ways
Blue- Blue is a very calming color which is often used in bedroom to help people relax, the color helps the brain release relaxing chemicals. It also symbolizes trust, and is associated with the sky and heaven.

Red-Red is seen as the color of rage. It is a danger cue, people tend to flush when angry or preparing to attack. (although red is seen in a negative light, it also has its positive side, red can make people physically stronger and faster and red also symbolizes love and power)

Yellow-Yellow is an optimism cue for the brain. Yellow also encourages communication and activates memory. yellow also stimulates the nervous system.
Taken from here: