Is anyone familiar with a possible evolutionary explanation of the placebo effect? It seems strange to me that the body would have a limit to the degree it heals itself, and that this limit gets bypassed by the belief that one is receiving treatment.
The only explanation I could string together is that the body limits how much it heals itself because it’s conserving energy/resources/whatever it might need for other things (periods of scarcity, danger, etc.) Receiving medicine sends the signal that the person is being taken care of and thus at a much lower risk of needing to use it’s ‘reserves’, so the body goes ahead and diverts them to repairing whatever is wrong with it.
However, this would suggest that a self-administered placebo would be ineffective, whereas treatment but no medicine by a doctor/caregiver would be effective. As far as I know, this isn’t how the placebo effect works, but I’m not exactly up to date on the subject.
Yes, that the original papers advocating the placebo effect were misleading in their reports and the popularisations thereof grossly exageratted.
Placeobo’s can be shown to reliably have an effect on:
Experience of symptoms.
Even more so on reports of symptoms (that is, the presence of an expectant experimentor messes with people’s heads big time.)
Psychological state.
Things that are significantly influenced by psychological state. The main two actual physical conditions that I can recall being genuinely altered by placebo (as opposed from being perceived to be altered) are ulcers and herpes virus (cold sores). Basically, two conditions that you more or less get from being stressed.
(I am not criticising the use of placebo controls here. But I am asserting that the primary benefit from such controls is in ‘balancing out’ other biases rather than because of direct effect of placebos on healing.)
A self-administered placebo might still be effective for evolutionary reasons. It would signal that a reduced activity level is related to tending your injuries, rather than, say, waiting in ambush or ‘freezing’ to avoid notice by motion-sensitive predators, so it’s safe to divert resources toward repair or antibody production at the expense of sensory and muscular readiness.
Same reason people have a hard time getting to sleep in unfamiliar circumstances, but focusing on a token reminder of home dispels the feeling.
People are very much affected by what they imagine is going on. For the unbendable arm you don’t tell people to extend their arm effiiciently, you have them imagine the arm extending out to infinity, or imagine the arm as a firehose.
I’m not sure why any of this works—it may have something to do with activating one’s own mirror neurons, but I do think the placebo effect should be viewed as a special case rather than a thing in itself.
Is anyone familiar with a possible evolutionary explanation of the placebo effect? It seems strange to me that the body would have a limit to the degree it heals itself, and that this limit gets bypassed by the belief that one is receiving treatment.
The only explanation I could string together is that the body limits how much it heals itself because it’s conserving energy/resources/whatever it might need for other things (periods of scarcity, danger, etc.) Receiving medicine sends the signal that the person is being taken care of and thus at a much lower risk of needing to use it’s ‘reserves’, so the body goes ahead and diverts them to repairing whatever is wrong with it.
However, this would suggest that a self-administered placebo would be ineffective, whereas treatment but no medicine by a doctor/caregiver would be effective. As far as I know, this isn’t how the placebo effect works, but I’m not exactly up to date on the subject.
Has anyone seen a better explanation?
Yes, that the original papers advocating the placebo effect were misleading in their reports and the popularisations thereof grossly exageratted.
Placeobo’s can be shown to reliably have an effect on:
Experience of symptoms.
Even more so on reports of symptoms (that is, the presence of an expectant experimentor messes with people’s heads big time.)
Psychological state.
Things that are significantly influenced by psychological state. The main two actual physical conditions that I can recall being genuinely altered by placebo (as opposed from being perceived to be altered) are ulcers and herpes virus (cold sores). Basically, two conditions that you more or less get from being stressed.
(I am not criticising the use of placebo controls here. But I am asserting that the primary benefit from such controls is in ‘balancing out’ other biases rather than because of direct effect of placebos on healing.)
http://news.ycombinator.com/item?id=567913
Now that is just freaky.
A self-administered placebo might still be effective for evolutionary reasons. It would signal that a reduced activity level is related to tending your injuries, rather than, say, waiting in ambush or ‘freezing’ to avoid notice by motion-sensitive predators, so it’s safe to divert resources toward repair or antibody production at the expense of sensory and muscular readiness.
Same reason people have a hard time getting to sleep in unfamiliar circumstances, but focusing on a token reminder of home dispels the feeling.
People are very much affected by what they imagine is going on. For the unbendable arm you don’t tell people to extend their arm effiiciently, you have them imagine the arm extending out to infinity, or imagine the arm as a firehose.
I’m not sure why any of this works—it may have something to do with activating one’s own mirror neurons, but I do think the placebo effect should be viewed as a special case rather than a thing in itself.