Rating attractiveness: study finds consensus among men, not women
wfu.edu
wfu.edu
The more life beats you down the more you appreciate a great a smile and the way it makes you feel. And also, one learns to be more wary of people who aren't smiling.
PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/19469598
I'm interested in the numbers obtained in the study -- how much variance among men, how much among women, etc.
Better ask soon, the popular press will probably whip up this story and deplete his reprint copies soon.
http://norvig.com/experiment-design.html
before taking this as the last word on the subject.