The 8 women were grouped based on foot size:
The women used for the face on the left had unusually small feet, and the women used for the face on the right had unusually large feet. I think it's clear that the small-footed morph is prettier, but the evolutionary psychologists effort at an explanation strikes me as a particularly silly example of after-the-fact bullshit.
As usual, the more attractive thing is presented as representing better health and suitability for producing offspring. But don't you think the woman on the right looks healthier?
Interestingly, the morphs done on male faces found that women were especially attracted to the faces morphed from men with small wrists. Explain that, oh, evolutionary psychologist bullshit artist. Of course, they can explain it, because they are up for explaining everything that happens to be.