Echoism, Facial Symmetry

Edler cited research supporting the claim that bilateral symmetry is an important indicator of freedom from disease, and worthiness for mating. Facial asymmetries and minor physical anomalies begin to appear early in embryonic development, mainly the first trimester of pregnancy, and can be a sign of instability during this growth. Fluctuating asymmetry (random differences between two sides, as opposed to the deliberate natural asymmetry in some animals) develop throughout the lifespan of the individual and is a sign of the phenotype being subjected to some levels of stress.
The ability to cope with these pressures is partly reflected in the levels of symmetry. A higher degree of symmetry indicates a better coping system for environmental factors. While the visible signs of this may not be particularly apparent, it is thought that they have at least a subconscious effect on people's perception of their beauty. Zaidel et al. in an empirical study upholds the claim that facial symmetry may be critical for the appearance of health. Their study disputes, however, the beauty or attractiveness claim.
Facial symmetry is neither the only trait nor is it necessarily the most important trait of what a culture considers attractive. A competing aesthetic theory is wabi sabi. Characteristics of the wabi-sabi aesthetic include asymmetry, asperity, simplicity, modesty, intimacy, and suggest a natural process. Both symmetry and asymmetry may have aesthetic appeal that also play a role in art. The asymmetry which does not mean the conjunction of two parts that are completely unalike and unrelated to each other but the conjunction of similar and related parts that are to some extent contrasted to one another is considered to have the most aesthetic appeal.