Mental Hygiene Tips
Before you believe something, and definitely before you pass it on, perform these steps:
1. Type it into Snopes. Has Barbara already done the research for you and shown it to be inaccurate? She's pretty good at that stuff, and it's her full-time job.
2. If there are quantifiable elements, punch the figures into a calculator. Do the numbers check out?
3. Does the claim violate what are generally accepted as fundamental ways the physical universe works? If so, ask how much of human knowledge, research, and understanding would have to be overturned. If it's "a great deal", consider whether it's more likely that the claim is untrue.
4. Would the claim's truth or falsehood have any easily-observable effects? If so, are they happening? For instance, if people could psychically predict cards, would casinos still be in business? If any newspaper psychics could foresee the future, how did all of them miss the 9/11 attacks?
5. Consider if the claim immediately benefits the claimant. If so, be on your guard.
These are all before you even have to start wondering whether someone's personal testimony is reliable, whether data was collected rigorously, whether testing procedures were adequate, etc. -- even before you worry about whether the people in the story actually exist or not.
And with particular relevance to email forwards: if the email contains "The New York Times published an article quoting...", "Researchers in the journal Science have shown...", "A bill has been introduced in Congress that...", or any similar construction, do a quick check whether the article, paper, or bill exists. It is stunning the number of times that someone just made it up.
Another domain of oft-fabricated data is supposed quotes from prominent people. In America, Founders and Framers, Presidents, peace activists, and well-known scientists and intellectuals are probably most-often treated this way. I notice this most frequently in claims about religion and politics, and in expressions of fatuous inspiration (for instance, Einstein did not say he believed in God, Emerson did not define success in terms of laughter and gardening, and John Adams did not say the U.S. was supposed to be a theocracy, even if someone might have wanted them to.)