Exercise 1: Why Double Blindfolding Was Necessary in 1784 — Possible Solution ================================================================================ If only the subjects had been blindfolded while the investigators still knew who was receiving the "genuine" magnetism versus a sham procedure, the investigators themselves could have unconsciously influenced the outcome - for example, through subtle differences in tone of voice, body language, or how carefully they described the procedure to a subject they knew was receiving the real treatment versus the fake one. A subject can pick up on unintentional cues even without being told directly, undermining the whole point of blindfolding them in the first place. By blindfolding investigators in some of the real tests as well, the commission removed even that indirect channel of influence - investigators who genuinely didn't know which condition they were administering couldn't unconsciously signal it to the subject, no matter how subtle the cue might have been. This mattered specifically because the commission's own real question was whether animal magnetism itself, and not the subject's own expectation, produced the observed effects. If investigators who knew the true condition could have leaked information even unintentionally, any effect found could have come from that leaked information and the subject's resulting expectation, rather than proving anything real about magnetism - blindfolding both sides is what let the commission isolate expectation as the true underlying cause. ANSWER: If only subjects were blindfolded, investigators who knew the true condition could still unconsciously leak cues through tone, behavior, or manner - undermining the blindfolding's own purpose. Blindfolding investigators too removed that channel, letting the commission conclude the resulting effects came from the subjects' own expectation and imagination, not from any real, independently existing force being channeled by the investigator. WHY THIS WORKS AS AN ANSWER ------------------------------ This explains the specific real mechanism (unconscious investigator cues) that double blindfolding closes, rather than only stating that more blindfolding is generally more rigorous.