Credibility of sources. I learned this in 40 minutes of a medieval history class. It is simply the constant habit of asking:
Who is speaking?
Why are they speaking?
What have they to gain or lose from speaking?
What have I to gain or lose from believing/disbelieving what is said?
I actually by instinct tend to believe people are mostly speaking in good faith so this is a great corrective for me. Also I have a habit of seeking reassurance instead of allowing bad news to register. So again a good corrective.
Yes indeed I had neglected the "To whom"...which reminds me how often I think a message is aimed at me (egomania) when in fact it has an audience I am not even aware exists...
Follow the money. If you can't see a person's motivations (esp. a politician), watch the result of their actions and assume that the outcome was their motivation and tell them that. Practically it doesn't matter whether they intended for that outcome to occur or not, because you still have to bear the consequences. If they predict the undesirable outcome, they should alter their behaviour. If the same behaviour repeatedly maps to the same outcome regardless of who is doing it, judge the person on the outcome. Drunk driving laws work like this.
My introduction to this were the excellent books 1421, 1434, and of course, the author's third book, The Lost Empire of Atlantis, which I found every bit as convincing as the first two and really drove home how credulous I'd been when reading them.
Who is speaking?
Why are they speaking?
What have they to gain or lose from speaking?
What have I to gain or lose from believing/disbelieving what is said?
I actually by instinct tend to believe people are mostly speaking in good faith so this is a great corrective for me. Also I have a habit of seeking reassurance instead of allowing bad news to register. So again a good corrective.