Blue is the color of the mind and is essentially soothing; it affects us mentally, rather than the physical reaction we have to red. Strong blues will stimulate clear thought and lighter, soft blues will calm the mind and aid concentration.
Consequently it is serene and mentally calming. It is the color of clear communication. Blue objects do not appear to be as close to us as red ones. Time and again in research, blue is the world's favorite color. (ref. Colour Affects)