My friend John Baez pointed me to an interesting news story. This reports research on the effects of explaining to hotel maids that they do more exercise than the recommended daily amount. The odd thing is that many such workers' bodies don't reflect this physical activity, and at the same time they report themselves as doing little exercise. When one randomly selected group had the truth explained to them, there was a decrease in their weight and waist-to-hip ratio - and a 10 percent drop in blood pressure.
Naturally, one might think that this information must have altered other aspects of the maids' lives. Perhaps they were now behaving in a healthier way. An expert is wheeled in to suggest this must be so as the placebo effect only alters subjective aspects of health.
With all the evidence available (some touched on here, here, and here), could it be that the belief that placebos only effect one subjectively is a defense against the troubling thought that language can have an effect on our body?