What can one do with photos like these, which show some ladies and some hats?
Show them to three-month-old infants, and then publish a study. One of the few groups to do exactly that published this study:
“How a Hat May Affect 3-Month-Olds’ Recognition of a Face: An Eye-Tracking Study,” Hermann Bulf, Eloisa Valenza and Chiara Turati, PLoS ONE, December 11, 2013. The authors are at Università degli Studi di Padova and Università degli Studi di Milano – Bicocca.