Which Face Is Real? was developed by Jevin West and Carl Bergstrom from the University of Washingtion as part of the Calling Bullshit Project.
It acts as a kind of game that anyone can play. Visitors to the site have a choice of two images, one of which is real and the other of which is a fake generated by StyleGAN.
As to what motivated them, here’s a quote from the article:
Our aim in this course is to teach you how to think critically about the data and models that constitute evidence in the social and natural sciences.