A member of the Evidence Based Health listserv wrote about a workshop he taught on Evidence Based Medicine (EBM). It went pretty well, he thought until he overheard a conversation during one of the breaks. A doctor was recommending an herbal remedy to a friend with the comment: "It cleared my problem up really quickly." This demonstrated to him how readily we still accept anecdotal evidence instead of EBM.
I think it is just a fundamental characteristic of human nature to apply critical thinking skills to everything except a core set of beliefs that you hold near and dear to your heart.
Martin Gardner wrote a book "Fads and Fallacies in the Name of Science" [BookFinder4U link] that talked about bizarre beliefs such as the earth being hollow, flying saucers, Velikovsky, etc. and how passionately these beliefs are held by certain groups of people. He reports that he got a lot of letters back complimenting him on the great book and saying how he really outlined some very silly beliefs ... except for the chapter on [whatever]. The person would then explain how this belief really was obvious to anyone who had a bit of common sense.
One recent example springs to mind. A single study appeared showing a temporary increase in IQ among students listening to Mozart. Classical music lovers seized on this study and started lobbying for more music in the schools and marketing music CDs to turn your children into geniuses. There are lots of good reasons to encourage children to listen to Mozart, but we can't pretend that raising their IQs is one of them.
Now I count myself among those who love classical music, but I am surprised at how incautiously people embrace preliminary research that really needs careful replication before you take any serious action on these studies.
Perhaps the Mozart effect exists (though recent evidence seems to indicate not). Perhaps the herbal remedy really works (some herbal remedies have been shown to work well in randomized trials, others have been shown to do no better than placebo). But too many of us give a "free pass" to beliefs that are deeply entrenched in our souls.
If you are interested in this tendency, there is a wonderful review article by Robert MacCoun that has some very good examples of entrenched beliefs and our unwillingness to critically examine them (as well as our tendency to be overly critical of research that supports conclusions we fundamentally dislike).
Biases in the interpretation and use of research results. MacCoun R. Annu Rev Psychol 1998: 49; 259-87. [Full text] [PDF]
The Mystery of the Mozart Effect: Failure to Replicate. Stelle KM, Bass KE, Crook MD. Psychological Science 1999: 10(4); 366-369. [PDF]
The Mozart Effect. Carroll RT, The Skeptic's Dictionary. Accessed on 2003-06-09. skepdic.com/mozart.html
You can find an earlier version of this page on my original website.