Robert Todd Carroll, author of The Skeptics Dictionary and creator of the website Skepdic.com, mentioned in a recent newsletter that he has updated his definition for anecdotal evidence. He points out that anecdotes are unreliable because they are
- “prone to contamination by beliefs, later experiences, feedback, selective attention to details, and so on.”
and although these are “scientifically worthless”, their vivid details make them popular. But Dr. Carroll wisely does not totally rule out their use. A physician, he explains should listen to anecdotal evidence from individual patients, but has to be careful.
- “But the physician cannot be selective in listening to testimony, listening only to those claims that fit his or her own prejudices.”
Dr. Carroll also provides some other good definitions for related terms, and I am including the first sentence from each definition since they are so well written.
- Confirmation bias: Confirmation bias refers to a type of selective thinking whereby one tends to notice and to look for what confirms one’s beliefs, and to ignore, not look for, or undervalue the relevance of what contradicts one’s beliefs.
- Selective thinking: Selective thinking is the process whereby one selects out favorable evidence for remembrance and focus, while ignoring unfavorable evidence for a belief.
- Subjective validation: Subjective validation is the process of validating words, initials, statements or signs as accurate because one is able to find them personally meaningful and significant.*
A good book that Dr. Carroll cites, and which I have mentioned on several of my webpages is:
- Gilovich T. How We Know What Isn’t So: The Fallibility of Human Reason in Everyday Life. 1991, New York: The Free Press. ISBN: 0029117062.
Dr. Carroll also mentions another book, co-authored by Gilovich, “Why Smart People Make Big Money Mistakes and How to Correct Them: Lessons From the New Science of Behavioral Economics” that I have not yet read, but which sounds very interesting.