by Patrick Appel
If inequality does, to some degree, cause social problems, why? Wilkinson and Pickett emphasize that the mechanism here is social psychological: inequality creates anxiety about status and feelings of unfairness that eat at people. In the words of a chapter title, “inequality gets under the skin.” Unlike the volume of studies on the correlation between inequality and health, there is little research that directly tests this proposition. The authors collect a variety of suggestive evidence, such as laboratory studies on how people react to being put in low-status positions and primate studies on what happens when rankings among apes are messed with. But a lot of the case is built by argumentation and inferential stretch.