The Evolved Self-management System | Edge:
"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, 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 topersonality 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."