To add a bit more information, this book covers a number of studies on the placebo effect (since the citations are in the book, which I do not have access to now, I don’t know where to find the original studies.) These studies indicate that the strength of the placebo effect also varies according to the color of the medicine, with different colored pills acting as more effective placebos for different ailments, and that the placebo effect can outweigh the actual effects of a drug (so that a small dose of vomit-inducing medicine could cause less vomiting than the control group, which received no medicine, if offered as an anti-nausea medicine.)
Note that that study doesn’t itself have anything directly to do with the placebo effect. They made fake pictures of boxes of pills, with different colours, and asked people questions like “What do you think this drug would be used to treat?” and “How effective would you expect it to be?”. They didn’t give any drugs (real or fake) to anyone.
(That isn’t intended as a criticism of the study: it’s fine that it wasn’t studying the placebo effect—nor of acephalus’s citation of it: it does indeed have some relevant references. Just a cautionary note.)
To add a bit more information, this book covers a number of studies on the placebo effect (since the citations are in the book, which I do not have access to now, I don’t know where to find the original studies.) These studies indicate that the strength of the placebo effect also varies according to the color of the medicine, with different colored pills acting as more effective placebos for different ailments, and that the placebo effect can outweigh the actual effects of a drug (so that a small dose of vomit-inducing medicine could cause less vomiting than the control group, which received no medicine, if offered as an anti-nausea medicine.)
Relevant excerpts on colour and vomit.
And here’s a relevant study on Pharmaceutical Packaging Color and Drug Expectancy which has some references.
Note that that study doesn’t itself have anything directly to do with the placebo effect. They made fake pictures of boxes of pills, with different colours, and asked people questions like “What do you think this drug would be used to treat?” and “How effective would you expect it to be?”. They didn’t give any drugs (real or fake) to anyone.
(That isn’t intended as a criticism of the study: it’s fine that it wasn’t studying the placebo effect—nor of acephalus’s citation of it: it does indeed have some relevant references. Just a cautionary note.)