I have been really enjoying your magazine since I started reading it last year.

In the Humor in the Brain sidebar in Laughing Matters, by Steve Ayan, the picture of the brain with eyeballs actually looks pretty hilarious. I keep visualizing Slinky-style springs behind the eyeballs going Sproing!

Anyway, keep up the good work.

Meghan OConnell
via e-mail

I feel that Knowing Your Chances, by Gerd Gigerenzer, Wolfgang Gaissmaier, Elke Kurz-Milcke, Lisa M. Schwartz and Steven Woloshin, is a very important article. As a physician, I know it is often difficult to follow through with scientific recommendations. This difficulty results in part from a fearjustified or notthat runs through the medical community: if you do not do everything possible for a patient, no matter how small the benefit, you will be sued. The saying is, No one is ever sued for overtreatment. As acknowledged in the article, patients want certainty. They want to feel like everything that can be done has been done. This may not be the best physical approach, but it can be mentally reassuring to a patient and the family.

adapted from a comment at www.ScientificAmerican.com/Mind-and-Brain

Knowing Your Chances is a very good article. Although the authors touched on drug efficacy, I am sur-prised they did not invoke the concept of number needed to treat, or NNT. This statistic indicates how many people would have to take a particular drug to achieve the desired results in one individual.

For instance, note the NNT of 35 for statins (cholesterol-lowering drugs) in the primary prevention (avoiding a first-time event) of any bad thing (such as a heart attack), according to a table provided by the journal Bandolier, found at http://tinyurl.com/mrxngz. [Editors note: the URL has been shortened to make it easier to type into a browser.] Your doctor may advise you to take a statin if your cholesterol is slightly elevated, but he or she probably will not tell you that out of 35 people taking the drug for four years, only one person will actually benefit from it in terms of avoiding a coronary event or another bad outcome. I wonder how many people with slightly elevated cholesterol would feel this rather minimal risk reduction to be worth the cost and the potentially bad side effects of taking this type of drug for the rest of their lives.

adapted from a comment at www.ScientificAmerican.com/Mind-and-Brain

As a biological anthropologist and someone who has been through postpartum depression, it worries me to see too much eagerness to slap an adaptive explanation onto PPD, as anthropologist Edward H. Hagan does in Ask the Brains. As scientists, it is our responsibility to acknowledge that we cannot explain everything and that not everything has a purpose.

Sometimes things are coincidentaland sometimes they are the result of maladaptive traits being tagged onto adaptive ones. Perhaps the hormonal shifts themselves are highly adaptive, but their ability to completely throw a new mothers mind out of whack is not.

Assuming that everything is an adaptationor failing to present the possibility that there are good scientific explanations besides adaptive ones for certain phenomenaultimately undermines our credibility with those who do not wish to believe the adaptive explanations for which we do have good evidence. The scientific community (including myself, Hagan and Scientific American Mind) has a responsibility to the public to avoid simply providing stimulating or fascinating potential explanations using evolutionary theory. We also need to provide sound, proven explanations for phenomena that are only potentially evolutionary in origin.

adapted from a comment at www.ScientificAmerican.com/Mind-and-Brain

A few years ago I described the basic symptoms of PPD to a group of physicians but altered one important fact: I said that the sufferer was male. The response was a relatively bored and quite immediate: protein deficiency. I would respectfully suggest that in at least some cases of PPD, simple dietary modification to include higher levels of quality protein would moderate many of the symptoms.

Given the protein price paid by the mother for construction and maintenance of a growing baby, anything more than a short-term deficit in protein intake must result in a clinical deficiency.

I have applied this knowledge to my own practice and have observed, among those who have responded (approximately 30 to 35 percent of sufferers), an excellent resolution of their PPD symptoms. Those who failed to respond to dietary protein also reported a great many co-factors, and they required pharmaceutical or psychological support (or a combination of both).

Ashmore Health Centre
adapted from a comment at www.ScientificAmerican.com/Mind-and-Brain

Regarding Building around the Mind, by Emily Anthes, I had a good firsthand brush with this topic a couple of years back. My wife and I were on a tour of Frank Lloyd Wrights Fallingwater home in Pennsylvania. Upon reaching the master bedroom, half of the group headed straight to the balcony without looking to either side or paying any attention to the room. They stopped and apologized to the tour guide, who laughed and said, That happens on every tour, and theres a reason for that. This room is specifically designed to draw you out to the balcony. You did exactly as you were supposed to do.

Throughout the rest of the tour, I learned that Wright had built even more such behavior-influencing tricks into the building. I left even more in awe of his talents than I had been before arriving.

adapted from a comment at www.ScientificAmerican.com/Mind-and-Brain

Note: This article was originally printed with the title, "Letters."