Brain and face: communicating signals of health in the left and right sides of the face.

In human communication and mate selection the appearance of health sends signals regarding biological fitness. We compared the appearance of health in the sides of the face to previous results on left-right facial asymmetry in the appearance of beauty (1). The stimuli were created by aligning the left and right sides of the face each with its own mirror image. Here, participants viewed 38 pairs of left-left and right-right faces and judged which member of the pair looked healthier. No significant interaction emerged between decision (health vs attractiveness) and face side. Rather, in women's faces right-right was significantly more healthy and attractive than left-left, while in men's faces there was no significant left-right difference. In biology and evolution, health and beauty are closely linked and the findings here confirm this relationship in human faces.