As with young hipsters who like a band until they become popular, organic food eaters also seem to have adopted a 'moral halo' about their belief system - they think they are better than other people for buying organic pineapples.
It's social psychology, so set your woo filter really, really low - or just read this overview on Scientific American Blogs.
Eskine concluded that the people who saw the organic foods felt confirmed in their moral identities (in other words, they were self-satisfied), which made them less likely to help others. I think this could definitely be the case, but I also wonder if there’s an alternate explanation.That's what's great about social psychology. It can confirm anything, though it mostly only confirms what psychology undergraduates think about projects that get them extra credit in their classes.
Citation: Eskine, K.,'Wholesome Foods and Wholesome Morals? Organic Foods Reduce Prosocial Behavior and Harshen Moral Judgments', Social Psychological and Personality Science DOI: 10.1177/1948550612447114