Question: Human faces are all made of skin and bones, but why do we like more than others?

Joanna Bryson answered on 24 Jun 2013:

That’s a *very* interesting question. It’s something people are still trying to understand. We know that to some extent, what people like to look at is what they have seen before, or what reminds them of nice experiences. Another theory due to David Perrott in St. Andrews is that we like to see “average” faces (faces that are like a combination of lots of other faces), because these tend to be sort of “perfect”, and to show that you are very healthy. But the interesting thing is that the faces that are *really* beautiful are often different from average in one interesting way — like a very long nose. That seems to help us remember people.

Here are a whole bunch of Dave Perrett’s experiments on faces online: http://www.perceptionlab.com/WEBPAGE/Participate/Participate.html
Ha — I like that the URL says WEBPAGE in the middle. He’s a great neuroscientist & psychologist, but I guess that doesn’t need to make him a great programmer :-).