Beauty appears to be something so subjective that it seems odd there is an actual science behind it. Is it not just taste? Or can the feeling of attractiveness be triggered by one or several characteristics and we could answer the question for what we consider beautiful with some mathematical formulas and rational explanations?
“It's a famine of beauty, honey. My eyes are starving for beauty.”
André Leon Talley editor at large (Vogue)
The reason why we find certain things aesthetically pleasing is sometimes not as random or subjective as it seems: in nature & architecture, 1.618 (golden ratio also known as phi ratio) is a prevalent number and there is a good reason why we like the harmonies in western music; scales are generally equal tempered and thus the relationship of a song's notes (their frequencies) all follow the same ratios.
It is then not surprising that there has been research to find out if and how attractiveness of the human face can be measured.
There is a common conception that we're attracted to the archetype of a human being as it indicates fertility. If it is not human looking we're experiencing a healthy repulsion. Human is good as it tells us "Hey this (I mean he or she) is suitable for reproduction".
1990, psychologists Langlois and Roggman conducted a study about Averageness in order to show that a composite image of many overlaid faces (= the average) is in most cases more attractive than each individual face. There are also studies that suggest that it does not even matter if the faces used to create the composite are from allegedly attractive or unattractive subjects. The more faces are being used to create a composite face, the less pronounced an irregular feature or flaw would show up; so as a result of blending many faces into one individual blemishes and undesired skin complexions disappear. Further, any other irregularity such as asymmetries and large features would blend into a homogenous flawless (as in there is nothing unattractive about it) face.
Beautycheck, a study conducted by the University of Regensburg took this idea further and not only created average faces through digital composites but also tested other characteristics of beauty, body shapes and social perception. Turns out that a characteristic such as symmetry does have a slight impact but not a big one like previous literature suggested. However, childlike features had a fairly strong impact with both genders preferring faces that had at least some degree of "babyfaceness" features mixed in.
One of the concluding results showed that artificial faces scored better than the natural ones they derived from (for both male and female faces). When a number of faces were shown to a modeling agency, 88% of the selected faces (14 out of 16) for potentially being interesting were artificial.
Of course the experiment did not factor in personality which I believe plays an important part when judging beauty. It does however, give us an interesting insight on what we consider beautiful and how much our taste is seemingly influenced by our surrounding and subconscious ideas of evolutionary benefits. Price question: "if you grew up with chimps and would not be in contact with any other human beings for your whole life, what would you be attracted to?"