Fascinating blog--which for me always means work, because it fills my head with questions.
But first I'll go to the part that serves the argument so well--the Proctors. This episode has become iconic so that it makes your point clear before you delve into the details. We all know the story, we can all relate to the emotions, though of course (I hope) not to the pathological extent that Abigail goes to.
Questions started to swirl when I read about the discernible changes in the dorsal anterior cingulate cortex during episodes of envy and how this activation is also present as a response to social exclusion. I wondered if such a response might not be handy in primitive settings, or in other primates where hierarchy is important. Usually, when there is this sort of mechanism it somehow serves reproductive success.
My poking around in research journals (on this subject) began about an hour ago. Came across a few things that may tie in with your article. For example, this area of the brain is important in conflict resolution. Also, this part of the brain integrates "information from several dimensions of decisional space". In other words, the dACC is primed to compare--which goes to the heart of your blog. No wonder it's the seat of envy, if one of its chief jobs is to compare.
Other fascinating tidbits came my way about the dACC (one having to do with the index finger and the ring finger), but I'll spare you.
You can see I found the blog not only interesting, but stimulating. Thank you!