Red is a powerful color-but not just for its associations with things like passion and anger. For example, people suffering from temporary color blindness after brain injuries perceive red before any other color. When your brain sees the color red, your body actually has multiple responses. The color red has been shown to boost metabolism, as well as spark hunger-this may be the reason red is such a common color inside restaurants. Red also bolsters aggression, as well as increase blood pressure, pulse, and heart rate.