Jonathan Haidt in his excellent book, The Righteous Mind:
[Dan] Ariely summarizes his findings from many variations of the paradigm like this: “When given the opportunity, many honest people will cheat. In fact, rather than finding that a few bad apples weighted the averages, we discovered that the majority of people cheated, and that they cheated just a little bit.”
People didn’t try to get away with as much as they could. Rather, when Ariely gave them anything like the invisibility of the ring of Gyges, they cheated only up to the point where they themselves could no longer find a justification that would preserve their belief in their own honesty.
The bottom line is that in lab experiments that give people invisibility combined with plausible deniability, most people cheat. The press secretary (also known as the inner lawyer) 27 is so good at finding justifications that most of these cheaters leave the experiment as convinced of their own virtue as they were when they walked in.1
There is so much fascinating (and useful) information in this book that it was almost impossible to select a single quotation to post here.
Also, here’s a solid review of the book from a Christian perspective.
Haidt, Jonathan (2012-03-13). The Righteous Mind: Why Good People Are Divided by Politics and Religion (pp. 96-97). Knopf Doubleday Publishing Group. Kindle Edition.↩