NCBI ROFL: Classifying dogs’ facial expressions from photographs.

If IHasAHotdog is any indication, dogs display a variety of facial expressions. However, surveys of LOLanimals aren't necessarily scientific (though they can be), so these researchers took a more controlled approach by testing whether people can recognize different facial expressions on the same dog's face. How did they get the dog to make different expressions? Read on for a few of their LOL-worthy methods...