"Our work suggests morality is an important force shaping economic decision-making,” says Jennifer Stellar, a doctoral student in psychology at University of California, Berkeley, and lead author of the study. “Though we often think $50 is $50, these results demonstrate that when money takes on negative moral associations, its value is diminished.”
The findings help explain the psychology behind such economic trends as socially responsible investing and the boycotting of sweatshop-produced goods. They also shed some light on why companies go to great lengths to avoid the perception that they are accepting money from corrupt investors or are themselves profiting from illegal or unethical practices, researchers say."
A more cynical author would suggest this is a possible explanation for high CEO pay? I wouldn't of course ;)