Humphrey and Skoyles in an editorial for Current Biology about the unique human capacity for benefitting from snake oil:
“[Human] superiority in what we call ‘natural health care’ rests on two special features of human psychology. First, humans are remarkably good at using environmental information to forecast the costs and benefits of deploying their biologically-based health defenses. Second, they are remarkably susceptible — benignly susceptible as it turns out — to culturally-based ‘medical disinformation’ in the guise of placebo treatments.”
The article is profound and complex: a bunch of intriguing speculation about why humans have a fairly robust placebo effect. Much of it seems sound to me. Some of seems pretty far out on a limb. But it’s all interesting.
The authors explain that we humans have a somewhat paranoid “health governor” that plays it safe, stingily deploying self-healing resources (e.g. immunity) based on pessimistic, better-safe-than-sorry predictions about our ability to afford them. Sometimes too stingy, no doubt:
“The health governor will be able to provide only rather coarse-grained prediction and control. It will have evolved to get things right on average.”
But these cautious predictions are probably too pessimistic in the modern era, when the outlook is rarely as bad as it was in Olden Times (winter no longer synonymous with foot shortages). And so we benefit disproportionately from being fooled into optimism by bullshit cures:
“Humans discovered the potential of fake medical treatments — treatments that, while being quite useless in themselves, could produce the illusion that the forecast was better than it actually was, and so release self-cure that the health governor would otherwise have held back.”
Right or wrong, that’s an elegant idea. If there’s a major flaw here, it’s probably the faith that The Placebo Effect is so medically impressive that it needs a fancy explanation like this. To curb your enthusiasm about placebo, see Placebo Power Hype.