http://www.newscientist.com/article/dn6355-babies-prefer-to-...
(They didn't do any averaging.)
This article says that symmetry specifically has also be found to be attractive to babies:
http://www.jyi.org/volumes/volume6/issue6/features/feng.html
Not sure if that was separate from the averaging mentioned.
http://www.grajfoner.com/Clanki/Perrett%201999%20Symetry%20A... seems to imply so. (I'm sure you can find something else stating the opposite though.) That paper was cited as a reference in the original beautification paper, which can be found here http://www.leyvand.com/research/beautification2008/attractiv....
I based my initial opinion on a documentary about someone who had tried to find the "typical criminal" face by averaging the mugshots of criminals. But to his shock, the resulting face kept turning out beautiful. But again, my google-fu fails me.