The characterization of a person as “beautiful”, whether on an individual basis or by community consensus, is often based on some combination of inner beauty, which includes psychological factors such as personality, intelligence, grace, politeness, charisma, integrity, congruence and elegance, and outer beauty (i.e. physical attractiveness) which includes physical attributes which are valued on an aesthetic basis.
Standards of beauty have changed over time, based on changing cultural values. Historically, paintings show a wide range of different standards for beauty. However, humans who are relatively young, with smooth skin, well-proportioned bodies, and regular features, have traditionally been considered the most beautiful throughout history.
A strong indicator of physical beauty is "averageness". When images of human faces are averaged together to form a composite image, they become progressively closer to the "ideal" image and are perceived as more attractive. This was first noticed in 1883, when Francis Galton overlaid photographic composite images of the faces of vegetarians and criminals to see if there was a typical facial appearance for each. When doing this, he noticed that the composite images were more attractive compared to any of the individual images. Researchers have replicated the result under more controlled conditions and found that the computer-generated, mathematical average of a series of faces is rated more favorably than individual faces. It is argued that it is evolutionarily advantageous that sexual creatures are attracted to mates who possess predominantly common or average features, because it suggests the absence of genetic or acquired defects. There is also evidence that a preference for beautiful faces emerges early in infancy, and is probably innate, and that the rules by which attractiveness is established are similar across different genders and cultures.