I was listening to an interview with Dan Ariely on NPR earlier today -- he was talking about topics from his latest book (The Honest Truth About Dishonesty) and he mentioned an experiment that I hadn't heard of before.
The experimenters took two strangers, put them in a room and let them introduce themselves and chat for ten minutes. Afterwards, the experimenters asked the subjects if they'd told any lies during the conversation, which both subjects denied. Then, they were presented with the audio -- and on average, people told 2-3 lies during that ten-minute conversation with a stranger. It's a stark illustration of Ariely's thesis in the book: we cheat (or in this case, lie) quite a bit, and we're able to do so in part because we're excellent at rationalizing it away.
So here's an exercise that I'm trying. Every time I notice that I'm lying to myself -- rationalizing an action that goes against what I've said I want, or against my principles, or whatever -- I'm making a note of it. It's … sobering, to say the least. I'm not exactly sure what I'm going to take away from it yet, but I can already see changes in my behavior as a result.