Its not what it does to your self perception, it is what it does to your perception of others.

Robert Frank, Thomas Gilovich, and Dennis Regan wrote two papers on this back in the 1990s that most of the professional economists out there already know. In one of their experiments, they asked undergraduates at the beginning and end of the semester several questions such as whether or not they would return $100 lost by a stranger at the end of the semester. They found that the proportion of students who gave more dishonest answers at the end of the semester than at the beginning was highest for students who took introductory micro from the mainstream economist, lower for students who took introductory micro from the developmental economist, and lowest for students who took introductory astronomy.

If there’s an effect here, I don’t think the mechanism is that economics makes you a bad person. Instead, it changes your expectations about what the rest of the world is like. If you are an altruistic person and someone teaches you that (a) most people are self-interested and (b) the world would be better if everyone behaved in a self-interested way, that is likely to make you behave in a less altruistic way.

But back to the original study: Money in general and large amounts of money in particular have become more accepted parts of general American culture than they were when I was a child. It seems quite plausible that this is also changing the way that Americans behave and making the ideology of individual autonomy even stronger than it already was. Which I don’t think is such a good thing.