This is slightly off topic (but not really); I saw a T.V programme not that long ago where a guy was asked to view various girl's faces - say out of 100 faces, which was he attracted to.
The info was put in a computer to 'map' the faces, and there was found to be a definite correlation in the structure of the faces that attracted him; if I remember rightly it was as complex as angles between eyes, nose & mouth.........
A composite was made to represent the 'perfect girl' (according to the guy who was tested).
That picture was put in amongst say 50 photos of other girls, and they were all shown to a group of young men. These guys were 'wired up' to detect changes in heart rate, respiration, whatever.............. Every single guy apparantly reacted more to that particular composite than to any other picture.
The brain is a wonderfully complex ' biological computer'; the study of which fascinates me....alas, mine needs replacing.