The Specter article gives a nuanced discussion of the complexity and ambiguities of alternative healing treatments. I am amazed that I had not been aware of results of neuroimaging studies that have tracked brain activity in response to either a drug or a placebo as soon as they are taken. One has shown that injection of saline that has been described as a drug can reduce a patient's symptoms of Parkinson's disease and caused in crease in brain dopamine that the disease destroys. A chemical basis of a pain relieving placebo effect was shown in a seminal 1978 experiment in which dental surgery patients who reported their pain was decreased by receiving an injection of saline instead of morphine had Naloxone added to their I.V. drips. Naloxone is a drug developed to counteract overdoses of heroin and morphine by blocking opioid receptors in the central nervous system that are normally acted on by endorphins. Naloxone blocked the placebo pain relief, proving that its chemical basis was most likely due to the actual relief of endorphins in the brain by the power of belief.
It appears that when we think we are receiving a drug that is capable of changing the level of a molecule that our body can manufacture (dopamine or endorphins in the examples just given) our body goes ahead and changes those levels by itself. There is objective chemical evidence that we can "heal ourselves". (The flip side of this is the "Nocebo Effect", in which the suggestion that a procedure is going to be painful actually cause it to be so, or enhance it.)
The Humphrey article looks at the larger context that he suggest enables these phenomena, and the reason that faith healing and medicine could be as effective as they were become they had any rational or scientific basis. Some edited chunks:
...until less than 100 years ago, there was hardly anything a doctor could do that would be effective in any physiological medicinal way—and still the doctor's ministrations often "worked". That's to say, under the influence of what we would today call placebo medicine people came to feel less pain, to experience less fever, their inflammations receded, and so on...I realized it must be the result of a trick that has been played by human culture. The trick isto persuade sick people that they have a "license" to get better, because they'rein the hands of supposed specialists who know what's best for them and can offer practical help and reinforcements. And the reason this works is that it reassures people—subconsciously —that the costs of self-cure will be affordable and that it's safe to let down their guard. So health has improved because of a cultural subterfuge. It's been a pretty remarkable development.Noting the overwhelming evidence that our character is molded by sub-conscious environmental and cultural cues he continues:
To explain placebos I think we need to invoke the existence of an "evolved health management system". The placebo effect is a particular kind of priming effect. And what I want to do now is to explain a whole range of other priming effects by invoking the existence of an "evolved self-management system".
It makes sense that our brains should have come to play a crucial part in the top-down management of bodily health. As I see it, what the health management system has evolved to do is to perform a kind of economic analysis of what the opportunities and the costs of cure will be: what resources we've got in reserve, how dangerous the situation is right now, what predictions we can make of what the future holds...So now, where does the placebo effect fit in? Placebos work because they suggest to people that the picture is rosier than it really is. Just like the artificial summer light cycle for the hamster - which causes them to mount a more massive and effective immune response to infection, because it is not as important to conserve resources in the summer as in the winter - placebos give people fake information that it's safe to cure them. Whereupon they do just that.
This suggests we should see the placebo effect as part of a much larger picture of homeostasis and bodily self-control. But now I'm ready to expand on this much further still. If this is the way humans and animals manage their physical health, there must surely be a similar story to be told about mental health. And if mental health, then—at least with humans—it should apply to personality and character as well. So I've come round to the idea that humans have in fact evolved a full-blown self management system, with the job of managing all their psychological resources put together, so as to optimise the persona they present to the world...our ancestors already had a template for doing these calculations, namely the pre-existing health system. In fact I believe the self management system evolved on the back of the health system. But this new system goes much further than the older one: it's job is to read the local signs and signs and forecast the psychological weather we are heading into, enabling us to prejudge what we can get away with, what's politic, what's expected of us. Not surprisingly, it's turned out to be a very complex system. That's why psychologists working on priming are discovering so many cues, which are relevant to it. For there are of course so many things that are relevant to managing our personal lives and coming across in the most effective and self-promoting ways we can.
Because our circumstances have generally improved in the last ten thousand years, and yet evolutionary catch-up occurs relatively slowly, this means that both systems will have become "out of date" in the way they calculate costs and benefits. At both the health-level and the self-level, there are bound to be things humans could not risk doing in the past that they can risk now.
Placebo medication works by tricking the subject with false information into believing the situation warrants a reduction in pain, for example, or the mounting of an expensive immune response. Yet it's precisely because our environment today is less dangerous than it used to be, that responding to this trick no longer puts us at an unacceptable risk...because the same kind of improvement has occurred in our social lives, the same goes for the risks with managing the self. In the "environment of evolutionary adaptiveness"—the social and physical environment, 100,000-10,000 years ago, in which many of our biological adaptations were laid down—our ancestors lived in very small scale societies, where individuals were monitored all the time by the group, and it was essential to conform to others' expectations...We no longer live in such an oppressive environment. We no longer need to play by the old rules, and rein in our peculiar strengths and idiosyncrasies. We can afford to take risks now we couldn't before...I think it really ought to be possible to devise placebo treatments for the self, which do indeed induce them to come out from their protective shells —and so to emerge as happier, nicer, cleverer, more creative people than they would ever otherwise have dared to be.