Disgust may not be a straightforward extension of the immune system’s aversion to harmful substances, but rather “a psychological nebula, lacking definite boundaries, discrete internal structure, or a single center of gravity,” says psychologist Nina Strohminger.Photograph by Star Stock / Flickr Nina Strohminger, perhaps not unlike many fans of raunchy comedies and horror flicks, is drawn to disgust. The University of Pennsylvania psychologist has written extensively on the feeling of being grossed out, and where it comes from. The dominant idea, developed by Paul Rozin and April Fallon...