I guess it's poorly or incompletely worded. This is an "active placebo". Another example would be determining something about mystic experiences and testing am

I guess it's poorly or incompletely worded. This is an "active placebo". Another example would be determining something about mystic experiences and testing amphetamine against psilocybin. You need something active, because otherwise even a drug-naive participant quickly groks they're on sugar and not an actual drug