Even though blue is generally considered a favorite, the University of Georgia study found it was green that scored the highest levels of positive feelings. Why? “Because it reminds people of nature,” say researchers. McLeod agrees: “When you feel the need for calm, use green for good health, peace, space and harmony.” If you take on a greenish pallor, however, expect women to notice first. In 2007, researchers at Newcastle University in the U.K. found that women were better able to discern green because of a “robust sex difference in the red-green axis of human vision.” They suspect that women, as caregivers, may have evolved a particular sensitivity to changes in skin colors to detect illness in their offspring.