Rational as I may be I sometimes engage in superstitious behaviors because of advice I have heard a long time ago and then stuck. For example, when I have a flu I usually overdose on C-vitamin. I believe that this piece of advice was made famous by Nobel prize winning scientist Linus Pauling who asserted that C-vitamin could cure the common cold. According to other sources that I trust more on this particular issue, such as Harriet Hall, also know as the "Skep Doc", a C-vitamin overdose will at best shorten the common cold for a day, and that is for people who do not eat a lot of C-vitamin in the first place (I am one of them why I may perhaps benefit somewhat), at worst a C-vitamin overdose can make you quite sick.
Two other behaviors which I sometimes engage in is drinking coca cola when my stomach is upset, and eating garlic when I have the common cold. Quick google searches did neither prove or disprove the efficiency of these two questionable treatments. Perhaps someone out there know something about it (in which case I hope you will share your knowledge).
What I really wanted to write about in this post is an article published in the British Medical Journal in which widespread myths, often reinforced by doctors were punctured. Some of these myths I believed in firmly until I saw the article. For example I have thought for a long time that reading in dim light is bad for your eyes. Now, becuase of this article, I know that there is no good evidence to back this claim. I had been wrong, but now I have changed my provisional world model to fit the new data (I stand corrected to put that more simply).
However, I am proud to say that I never bought into the myth that you only use 10% of your brain. Then again, I am a brain researcher so perhaps I cannot brag to much about this accomplishment. The idea, though popular in books such as Uri Geller's "Little Mind Power Book", is completely absurd. Would evolution allow 90% of our brain just sit there and do nothing, I think not. By the way, the claim can be easily disproved by sending a person into an FMRI and watch how the entire brain lights up which is an indication of energy expenditure (maybe with the exception of people like Uri Geller). Furthermore, in contrast to predictions of the "we only use 10% of our brain" hypothesis, removal of almost any part of the brain will result in clear symptoms,
The entire list of medical myths which are debunked in this nice article are as follows. Take a look at the article if you are not willing to take my word for it (there are nice references as well).
1. People should drink at least 2,5 litres of water per day
2. We only use 10% of our brains
3. Hair and fingernails continue to grow after death
4. Shaving hair causes it to grow back faster and be coarser
5. Reading in dim light ruins your eyesight
6. Eating turkey makes people especially drowsy
7. Mobile phones cause electromagnetic interference in hospitals