For research recently published in the journal Evolutionary Psychology, Robert R. Provine, a professor of psychology at UMBC, gathered hundreds of slides of crying and non-crying people from photo sharing sites like Flickr. With some simple Photoshopping, tears were removed from the shots of crying people. The tear-free images and their teary counterparts were shuffled in with a long sequence of portraits of people with neutral expression and shown to undergraduate volunteers.
Excerpted from www.epjournal.net. Read the whole article here.