Every now and again we discover that some of our beliefs are supported by scientific research. Recent research using functional Magnetic Resonance Imaging (fMRI) shows that "vegetarians and vegans appear to have more of an empathetic response to both human and animal suffering ... FMRI brain scans showed that the areas of the brain associated with empathy (such as the anterior cingulate cortex and the left inferior frontal gyrus in this study) were more activated in vegetarians and vegans compared to omnivores when all three groups were shown pictures of human or animal suffering. Written questionnaires on empathy, in both this and other studies, seem to confirm higher empathy levels in vegetarians and vegans (Preyo and Arkiwawa, 2008; Filippi et al 2010)." (I could not find the reference to Preyo and Arkiwawa, 2008 but the entire essay by Filippi et al., 2010 is here.)
I've been thinking about this general topic and relationship for a long time and I agree with the conclusion of the essay in which these results are reported, namely that "Most animal advocates also care deeply about a broad spectrum of social justice and humanitarian causes." I've always believed that "compassion begets compassion" and easily crosses species lines. I welcome more research in this area from both social scientists and neuroscientists.