While hardly a "double blind IQ test", or a microdose, Ken Kesey described an interesting lab experience. Back when there was still academic research being done

While hardly a "double blind IQ test", or a microdose, Ken Kesey described an interesting lab experience. Back when there was still academic research being done on psychedelics, he was part of an experiment group. One of the experiments being done on him was measuring his sense of time (the "time dilation" often reported by users). They would ask him to estimate one minute passing by, while they timed it. But before they did the time test, they took his pulse, and wrote the results where he could see them. So when they asked him to time one minute, he simply counted his pulse - presumably hitting his estimate more accurately than a "sober" person could. I think this particular incident says a lot about the difficulty of doing scientific research around perception, for something that so radically alters perception.