This is the key. The placebo effect only works for subjective measurements that the patient has to report qualitatively. A placebo asthma treatment will cause patients to report that their breathing has improved, but it won’t change how much air is actually going into and out of their lungs. This makes it useless for most things. Maybe it’s ok for pain, since pain is purely perceptual anyway, but for anything else it’s just going to cost people money without actually helping them.
There's a little more than pain - anxiety is another example where just having something to take can help immensely. But yes, in general placebo is greatly over-hyped and oversold with much influence from people who believe in 'healing energy' and mind-over-body practices and such.
That’s a good point. For pain and anxiety and other mental states it’s probably ok to give someone a placebo if it convinces them to change the state of their own mind, provided they have asked for the change.
They haven't even necessarily changed the state of their mind. It's hard to accurately report your own subjective experiences in a measurable way. Maybe you're not sure where your pain falls on a 1-10 scale. There's a range of numbers you think might fit how you feel.
Before a placebo treatment, you pick something at the higher end. After the treatment, you think maybe it helped, so you pick something on the lower end despite feeling the same.
Maybe you even feel worse than you did at the start of the study but you've gotten used to a higher baseline amount of pain and you're having a relatively good morning compared to that so you report a low number.
This is about how your self-reports change, not necessarily about how your state of mind changes.
But the number you report for the level of pain is a thought in your mind; it is the state of your mind, or a summary of it. If you report a different number, your state of mind must have changed.
Sure, every time anything happens to you, your state of mind is different. My point is that the relevant part of your state of mind doesn't necessarily change.
If you report a different number, that means some things in your mind changed. Those things may or may not include the level of pain you're experiencing.
Let's take an example with a bit more objectivity. If you ask me to rate how long a tv show is on a scale of 1-10 and I know the show is 30 minutes, how do I turn that into a 1-10 scale? Suppose I mostly watch shows with 12-minute episodes. This is relatively long, so I give it an 8.
Later I start watching hour-long shows. You ask me again how long this show is on a 1-10 scale. Now I put it at a 5. I don't think the show got shorter, and I don't experience it as being shorter. I just changed how I contextualize the length of shows for a 1-10 scale.
It would be silly to say that watching hour-long shows is a good way to shorten the mental experience of watching a 30-minute show.
