Immune reactivity and attractiveness.

Over the past decades, information about the characteristics of attractiveness has accumulated. We know about eight pillars of beauty, among them youthfulness, symmetry, hormone markers and body odor. But what is the biological function of these attractive signals? Is there one common function to be found in all eight beauty markers? In this paper, we argue that attractiveness signals immune resistance. Being attractive would thus be an honest signal for an immune system that coped well with the environmental challenges it was exposed to during ontogeny. This is a prerequisite for developmental stability, which again affects the differentiation of beauty characteristics. We argue that human preferences and mate choice criteria have evolved in coevolution with parasites, and that the current parasite load modulates our decision making.