In a season three episode of National Geographic's Brain Games, psychology professor Richard Russell's research on the psychology of beauty was discussed.
From the transcripts of Brain Games:
Even though almost everyone can be divided into one of these two categories - male of female - it's not always so easy to tell which is which. Like in that first image we showed you. Most of you decided the person on the left was female, and a few of you thought you outsmarted us by deciding the one on theright was the woman.
But these images are actually just slightly altered version of the same face. This illusion was created by Professor Richard Russell at Gettysburg College. Taking two identical images, the eyes and lips remained unchanged on both faces, while the image on the right was darkened everywhere else, and the one on the left was lightened. - making it appear more feminine so even though the eyes and lips may appear darker in the image on the left - in reality they're the exact same shade in both images!
So, with all of this information, can you identify the gender of our model now?